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INTRODUCTION  —  Kidney stone disease (nephrolithiasis) is a common problem in primary care practice. Patients may present with the classic symptoms of renal colic and hematuria. Some patients may be asymptomatic or have atypical symptoms such as vague abdominal pain, while others will have more typical symptoms, such as acute abdominal or flank pain, nausea, urinary urgency or frequency, difficulty urinating, penile pain, or testicular pain.

This topic will review the evaluation of the patient with established symptomatic stone disease (either newly diagnosed or recurrent stones) or asymptomatic stones. Other aspects of kidney stones in adults are discussed separately:

● (See "Kidney stones in adults: Epidemiology and risk factors" .)

● (See "Kidney stones in adults: Diagnosis and acute management of suspected nephrolithiasis" .)

● (See "Kidney stones in adults: Prevention of recurrent kidney stones" .)

● (See "Kidney stones in adults: Surgical management of kidney and ureteral stones" .)

GOAL OF EVALUATION  —  In patients with established kidney stone disease, the goal of a diagnostic evaluation is to identify, as efficiently and economically as possible, the particular behavioral and physiologic differences present in a given patient so that effective therapy to prevent recurrent stones can be established and the prognosis can be better defined. Thus, the type and extent of evaluation depend in part upon the following:

● The severity and type of stone disease

● Whether it is a first or a recurrent stone

● Presence or absence of systemic disease and/or risk factors for recurrent stone formation

● Family history of nephrolithiasis

● The patient's interest in stone prevention

APPROACH TO EVALUATION

Patients with established stone disease  —  All patients presenting with established kidney stone disease (either newly diagnosed or recurrent stones) should undergo a focused history, radiologic imaging, stone analysis (if available), and at least a limited laboratory evaluation. The approach for patients with asymptomatic stones is discussed elsewhere in this topic. (See 'Patients with asymptomatic stones' below.)

Focused history for stone risk factors  —  The purpose of the focused history is to identify stone risk factors, such as a family history of stone disease and certain dietary habits ( table 1 ). These factors are described in detail elsewhere. (See "Kidney stones in adults: Epidemiology and risk factors" .)

Summarized briefly, adverse dietary habits include:

● Low fluid intake or a high fluid loss (eg, from sweating or gastrointestinal losses), which leads to a lower urine volume and, therefore, a higher concentration of lithogenic factors.

● A very high animal protein diet, which can lead to higher excretion of calcium and uric acid and lower excretion of urine citrate ( figure 1 ).

● Higher sodium diet, which increases urinary calcium excretion [ 1 ].

● Increased intake of higher oxalate-containing foods, particularly spinach. The magnitude of the contribution of dietary oxalate to urinary oxalate is controversial and likely varies considerably from person to person due to differences in gastrointestinal absorption.

● Lower calcium intake, which acts by increasing the absorption of dietary oxalate and subsequent higher excretion of oxalate in the urine due to decreased calcium oxalate complex formation within the intestinal lumen [ 2,3 ]. The effect of lower calcium intake on raising urine oxalate more than counterbalances the decrease in calcium absorption and excretion.

● Excessive vitamin C and D supplementation, which may increase urinary oxalate or calcium, respectively.

● Excessive sugar (sucrose and fructose) intake, which may increase calcium and/or oxalate excretion.

In addition, certain medications can occasionally crystallize in the urine and lead to stone formation. Examples include atazanavir , sulfadiazine , and triamterene . (See "Crystal-induced acute kidney injury" and "Triamterene nephrotoxicity" .)

Radiologic testing  —  If not yet performed during the initial evaluation, radiographic examination, preferably with noncontrast, low-dose computed tomography (CT), should be obtained to search for residual stones within the urinary tract. Diagnostic tests for the detection of nephrolithiasis are discussed in detail elsewhere. (See "Kidney stones in adults: Diagnosis and acute management of suspected nephrolithiasis", section on 'Diagnostic imaging' .)

Stone analysis  —  Analysis of the stone is an essential part of the evaluation [ 4-6 ]. Patients should be encouraged to retrieve stones they pass spontaneously for analysis, although novel CT imaging techniques may permit noninvasive discrimination among the main subtypes of urinary calculi. Similarly, stones that are surgically removed should also be submitted for analysis. (See "Kidney stones in adults: Diagnosis and acute management of suspected nephrolithiasis", section on 'Determination of stone composition' .)

Number of stones to analyze  —  At least one stone should be analyzed in every patient. Given sampling issues, analyzing two stones provides useful information about other possible and/or relevant components. If the two stone composition reports are sufficiently similar, then future stones do not need to be analyzed unless there has been a clinically relevant change. However, some patients produce more than one stone type. In a study of patients with bilateral stones, for example, the major stone component was discordant between the two kidneys in 25 percent of individuals [ 7 ]. In this setting, it would be reasonable to analyze more than one stone that is passed from each side. Also, if a new stone forms after many years, it should be sent for analysis if passed or surgically removed.

Occasionally, treatment to prevent one stone type may inadvertently lead to the formation of a different stone type (though this is uncommon). As an example, over-alkalinization of the urine of a patient with uric acid stones could increase the risk of calcium phosphate crystal formation. Thus, analysis of a newly formed stone after the initiation of treatment is indicated.

Individual crystalline components  —  The most common crystalline materials found in kidney stones are calcium oxalate, calcium phosphate, uric acid, and struvite (magnesium ammonium phosphate). It is not uncommon for a stone to contain more than one crystalline component.

● Calcium oxalate – Calcium oxalate is the most common component found in kidney stones (approximately 70 to 80 percent). Calcium oxalate can be found in monohydrate and dihydrate forms ( picture 1A ). Calcium oxalate can also be present in combination with uric acid or calcium phosphate. Because calcium oxalate stones typically grow on a Randall's plaque (composed of calcium phosphate) on the papillary tip [ 8,9 ], a laboratory that examines the composition of the nidus may report a stone with an eccentric calcium phosphate nidus (usually 5 percent) and a calcium oxalate body (95 percent).

● Calcium phosphate – Calcium phosphate is found in approximately 15 percent of kidney stones and can be present in combination with calcium oxalate or struvite. Because of differences in solubility due to urine pH, calcium phosphate is not found mixed with uric acid. The two forms of calcium phosphate include apatite (sometimes reported as carbonate apatite), which is the crystal type found in bone, or calcium hydrogen phosphate (brushite); the frequency of apatite is much greater than brushite. Calcium phosphate crystals in the urine sediment are typically dark and amorphous.

● Uric acid – Uric acid is the most common crystal form that contains urate ( picture 2A ). Uric acid is present in approximately 8 percent of analyzed stones, sometimes in combination with calcium oxalate. Rare crystals that contain urate include sodium urate (which is present in the joint fluid of patients with gouty arthritis) and ammonium urate. (See "Kidney stones in adults: Uric acid nephrolithiasis" .)

● Struvite – Struvite is the crystal name for stones that form only in the presence of urease-producing bacteria (eg, Proteus mirabilis , Klebsiella pneumoniae , Corynebacterium species, Ureaplasma urealyticum ) in the upper urinary tract ( picture 3 ). Other names for this crystal type include "triple phosphate" (because the phosphate is in the triple-negative form) and magnesium ammonium phosphate carbonate apatite. Struvite is found in approximately 1 percent of analyzed stones and is much more common in females than in males (due to the higher risk of urinary tract infections in females). If a preexisting calcium-containing kidney stone is subsequently infected with a urease-producing bacterium, the stone analysis may report that the composition of the stone includes calcium oxalate or calcium phosphate in addition to struvite. (See "Kidney stones in adults: Struvite (infection) stones" .)

● Other crystal types – Rare crystal types include [ 10 ]:

• Cystine ( picture 4 ). (See "Cystinuria and cystine stones" .)

• 2,8-dihydroxyadenine (DHA) – DHA crystals form as a result of adenine phosphoribosyltransferase deficiency, a rare autosomal recessive disorder; DHA crystals may be incorrectly reported as uric acid by some laboratories [ 11 ].

• Triamterene . (See "Triamterene nephrotoxicity", section on 'Triamterene stones' .)

• Acyclovir . (See "Crystal-induced acute kidney injury", section on 'Acyclovir' .)

Clinical relevance  —  Knowing the composition of the stone assists with clinical decision-making for the treatment of existing stones and prevention of new stone formation. Examples of how this knowledge can impact clinical decision making include:

● Calcium oxalate monohydrate and brushite are hard stones and may not be fragmented as easily with shock wave lithotripsy.

● Uric acid stones form in acid urine, and alkalinization of the urine can both dissolve existing uric acid stones and prevent new stones from forming. (See "Kidney stones in adults: Uric acid nephrolithiasis", section on 'Urinary alkalinization' .)

● Calcium phosphate stones form in alkaline urine, and therefore, increasing the urine pH may increase the likelihood of calcium phosphate precipitation. While reducing the urine pH would be helpful, this is often not clinically possible for most patients who form calcium phosphate stones (for unclear reasons).

● The presence of certain stone types may indicate the existence of an underlying predisposing condition. As examples, calcium phosphate stones are more frequent in individuals with primary hyperparathyroidism and distal renal tubular acidosis, and struvite stones form only in the presence of an upper urinary tract infection. Uric acid stones may be more common in individuals with diabetes mellitus (due to impaired ammoniagenesis), metabolic syndrome [ 12 ], or gout. (See "Kidney stones in adults: Epidemiology and risk factors", section on 'Medical conditions' .)

When designing a preventive regimen for a patient, the individual components of the stone need to be considered:

● For pure stones, the focus is on modifying the urine composition to prevent the precipitation of that specific crystal type, even if the 24-hour urine composition suggests a high risk for precipitation of another crystal type. (See '24-hour urine collections' below.)

● For mixed stones, the treatment recommendations depend upon the specific components and the relative amounts present. As an example, for a stone that is reported to contain 95 percent calcium oxalate and 5 percent calcium phosphate, the focus should be on reducing the supersaturation of calcium oxalate. However, these two crystal types share risk factors (lower urine volume, higher urine calcium, and lower urine citrate), so modifying these components should reduce the risk of both crystal types. (See "Kidney stones in adults: Prevention of recurrent kidney stones" .)

Given the variability in reporting of mixed stones by commercial laboratories, it is important to keep in mind the clinical setting and other available information and to question the reliability of the stone composition report if it seems inconsistent with the patient's history. A report indicating the presence of struvite, for example, is probably inaccurate in a patient with no documented infection with a urease-producing bacterium. It is also important to examine the urine sediment for crystals as this might help identify the crystal type. (See 'Urinalysis' below.)

Laboratory testing

Approaches to laboratory testing  —  Three options have been proposed for laboratory evaluation after a first stone: a limited evaluation, a complete metabolic evaluation, or a targeted approach. Although there is disagreement whether a complete metabolic evaluation should be performed after the first kidney stone, there is general agreement that a complete metabolic evaluation is indicated in all patients with multiple stones at first presentation (including those who have passed a single stone but have other asymptomatic stones found in the kidney by imaging), patients with a strong family history of stones, individuals with active stone disease (defined as recurrent stone formation, enlargement of existing stones, or the recurrent passage of gravel), and patients with reduced bone mineral density. The decision about which option to pursue should be shared by the clinician and patient.

● Limited evaluation – A limited laboratory evaluation includes a urinalysis and routine blood chemistries. Some clinicians prefer this approach after a first stone because of the variable rate of stone recurrence and data suggesting that a comprehensive medical evaluation is not cost-effective for patients who have only formed one stone [ 13,14 ]. This approach is based upon the availability of nonoperative therapy for most symptomatic stones and avoids unnecessary therapy in those who would not have a recurrence. (See 'Urinalysis' below and 'Blood tests' below.)

● Complete metabolic evaluation – A complete metabolic evaluation consists of a urinalysis, routine blood chemistries, and at least two 24-hour urine collections for analysis of urine composition. Some clinicians recommend this approach after the first stone because of the potentially high rate of recurrence and potential morbidity from recurrent stones. Limited data suggest that single-stone formers have similar metabolic abnormalities as patients with recurrent nephrolithiasis [ 15,16 ]. In addition, there are several studies suggesting that the likelihood of stone formation can be predicted reasonably well from the 24-hour urine values [ 17-19 ]. This approach should be followed only in individuals willing to make changes to their diet or fluid intake or to take medical therapy if warranted by the work-up. (See 'Complete metabolic evaluation' below.)

● Targeted approach – A third approach is to base the extent of the laboratory evaluation upon an estimation of the risk for new stone formation [ 18 ]. A complete metabolic evaluation would be performed in patients at moderate to high risk for recurrent disease. Patients at high risk for recurrent disease include:

• Patients who have formed more than one kidney stone

• Patients with a family history of stones

• Patients with chronic diarrheal states and/or malabsorption, pathologic skeletal fractures, osteoporosis, urinary tract infection, diabetes, and/or gout

• Patients taking medication that may put them at higher risk (eg, topiramate , acetazolamide )

• Patients with stones composed of cystine, uric acid, or calcium phosphate

• Patients with dietary habits associated with higher risk of stone formation

Complete metabolic evaluation  —  The complete metabolic evaluation for nephrolithiasis consists of both blood and urine testing, including at least two 24-hour urine collections at baseline.

Urinalysis  —  A urinalysis should be performed on a voided urinary specimen. The urinalysis should include pH determination since a pH greater than 7.5 raises the possibility of a stone due to urease-producing bacteria, whereas a pH less than 5.5 favors uric acid lithiasis. (See "Urinalysis in the diagnosis of kidney disease" .)

The urine sediment should also be examined for crystalluria since particular crystal types may provide a clue as to the composition of stones (see "Urinalysis in the diagnosis of kidney disease" ):

● Uric acid crystals – Uric acid crystals are observed in acid urine (usually pH <5.5), a milieu that favors the conversion of the relatively soluble urate salt into the insoluble uric acid ( picture 2A-B ). (See "Uric acid kidney diseases" .)

● Calcium phosphate or calcium oxalate crystals – The formation of calcium oxalate crystals is not dependent upon the urine pH, while calcium phosphate crystals only form in a relatively alkaline urine (usually pH ≥6.5) ( picture 1A-B ). (See "Kidney stones in adults: Epidemiology and risk factors" .)

● Cystine crystals – Cystine crystals, with their characteristic hexagonal shape, are diagnostic of cystinuria ( picture 5 ). (See "Cystinuria and cystine stones" .)

● Magnesium ammonium phosphate crystals – Magnesium ammonium phosphate (struvite) and calcium carbonate apatite are the constituents of struvite stones ( picture 3 ) (see "Kidney stones in adults: Struvite (infection) stones" ). Normal urine is undersaturated with magnesium ammonium phosphate, and struvite stone formation occurs only when ammonia production is increased and the urine pH is elevated. Both of these requirements are only met when an upper urinary tract infection occurs with a urease-producing bacterium, such as Proteus or Klebsiella .

Blood tests  —  A routine chemistry profile should be obtained, including measurement of serum electrolytes, serum creatinine, and serum calcium. The results may help identify certain disorders, such as primary hyperparathyroidism, hyperuricemia, and distal renal tubular acidosis, that are associated with nephrolithiasis. (See "Primary hyperparathyroidism: Diagnosis, differential diagnosis, and evaluation" and "Kidney stones in adults: Uric acid nephrolithiasis" and "Nephrolithiasis in renal tubular acidosis" .)

● The serum calcium concentration should be measured looking for hypercalcemia; if high-normal (which we define as above the midpoint of the normal range), the serum calcium should be repeated. A measurement of intact parathyroid hormone is warranted in patients with serum calcium values in the high-normal range or if the urine calcium is high since primary hyperparathyroidism is often associated with only intermittent and mild elevations in the serum calcium concentration [ 20-22 ]. In one series of 48 patients with nephrolithiasis and primary hyperparathyroidism, 30 (63 percent) had serum calcium concentrations between 10.2 and 11 mg/dL (2.55 and 2.75 mmol/L) [ 20 ]. (See "Primary hyperparathyroidism: Diagnosis, differential diagnosis, and evaluation" .)

● Although usually in the middle of the reference range, the presence of a lower serum bicarbonate concentration raises the possibility of distal renal tubular acidosis or chronic diarrhea.

24-hour urine collections  —  An important component of the evaluation of patients at moderate to high risk for recurrent stone disease is the assessment of urine composition:

● Number of collections – At least two 24-hour urine collections should be obtained in the outpatient setting, with the patient following their usual diet, fluid intake, and physical activity. The differences among the collections are often substantial, so an important contributor may be missed in many patients if only one sample is collected ( figure 2 ) [ 23,24 ]. The validity of this approach was illustrated in the following studies:

• A study of 75 recurrent idiopathic calcium kidney stone formers examined the relative diagnostic utility of one, two, and three urine collections [ 23 ]. When compared with one or any combination of two urine collections, three urine collections were significantly associated with the highest yield of identifying a urinary abnormality ( figure 2 ).

• Similar findings were noted in another report of over 1000 stone formers in whom three 24-hour urine collections were obtained [ 24 ]. Differences in urinary biochemical risk factors among the three collections were substantial enough that an important metabolic abnormality would have been missed in many patients if only one sample had been collected.

Thus, we recommend that a minimum of two collections be performed as part of the initial evaluation.

● Timing of collections – The urine collections should be obtained while the patient is on their usual diet. Values should not be measured immediately after the acute stone episode; it is common practice to wait at least one to two months after a stone event to obtain the collections [ 23 ]. One should also wait at least one to two months after the patient has completely recovered from any interventions, such as shock wave lithotripsy, ureteroscopy, or percutaneous stone removal. Ideally, the patient should be free of pain, infection, and obstruction and following their "usual routine" when performing their urine collections.

● Tests to include – The urine volume and excretion of calcium, uric acid, citrate, oxalate, creatinine (to assess the completeness of the collection), pH, sodium, potassium, and magnesium should all be measured. Ideally, the supersaturation of lithogenic substances should be calculated. The results of the urine collections and stone analysis (if available) dictate subsequent evaluation and management. (See "Kidney stones in adults: Prevention of recurrent kidney stones" and "Kidney stones in adults: Struvite (infection) stones" and "Kidney stones in adults: Uric acid nephrolithiasis" and "Cystinuria and cystine stones" .)

A variety of definitions for "normal" are used by different laboratories for each of the urinary parameters. Below are some more common definitions:

• Calcium − Less than 200 mg (5.0 mmol) per day in females or less than 250 mg (6.25 mmol) per day in males

• Uric acid − Less than 750 mg (4.5 mmol) per day in females or less than 800 mg (4.8 mmol) per day in males

• Oxalate − Less than 40 mg (0.44 mmol) per day in both females and males

• Citrate − Greater than or equal to 450 mg per day in both females and males

However, the values for these definitions are arbitrary and additional data suggest a more linear relation for each of these factors. As an example, the risk continues to decrease as urinary calcium falls below 250 mg/day (6.25 mmol/day) in both males and females [ 25 ]. In addition, the concentration of lithogenic factors and the urinary supersaturation, as calculated in an experienced laboratory, are more important than the absolute amounts with respect to stone formation [ 25 ]. The definition of "normal" for calculated supersaturation is also arbitrary; the risk continues to decline even when the supersaturation is lower than the threshold [ 26 ].

Measurement of sodium excretion is also important. Higher sodium intake can contribute to increased calcium excretion and will affect the response to a thiazide diuretic when prescribed to reduce urine calcium. (See "Kidney stones in adults: Epidemiology and risk factors" .)

In many laboratories, two or three separate collections are required to obtain all of this information: uric acid is measured in a plain or alkaline solution, calcium and oxalate are measured in hydrochloric or nitric acid, and citrate is measured in an acidified solution. However, some specialized laboratories provide a kit that permits all of the above values to be measured and urinary supersaturation to be calculated from a single urine collection, thereby making it easier for the patient and more likely that the required information will be obtained [ 27-29 ].

Monitoring for new stones  —  Radiologic monitoring, usually with ultrasonography, abdominal radiography, low-dose, noncontrast CT, or digital tomosynthesis, is warranted for the detection of new stones. Monitoring should be performed initially at one year and, if negative, every two to four years thereafter depending upon the severity of the stone disease and the 24-hour urine values. (See "Kidney stones in adults: Diagnosis and acute management of suspected nephrolithiasis" .)

Several factors should be considered when choosing which modality to use for radiologic monitoring:

● If stones were previously visible by ultrasonography, then using this modality will minimize cumulative radiation exposure; this is particularly important in patients of childbearing age.

● To allow comparisons of stone burden over time, a modality should be selected that successfully detected the number and size of previous stones. As an example, ultrasound should not be used for radiologic monitoring if prior stones were only quantifiable with noncontrast CT, abdominal radiographs, or digital tomograms.

● Noncontrast CT remains the most sensitive test for detecting stones, particularly small stones, but is an expensive option for routine monitoring of stone burden [ 30 ]. Digital tomosynthesis, a high-resolution radiograph-based imaging technique that is used routinely for breast cancer screening, may be an effective and lower cost alternative to noncontrast CT. One retrospective study comparing digital tomosynthesis with noncontrast CT for the follow-up of nephrolithiasis found similar stone detection rates between the two imaging modalities [ 31 ]. Digital tomosynthesis has also been shown to have lower radiation exposure compared with noncontrast CT [ 32,33 ]. (See "Kidney stones in adults: Diagnosis and acute management of suspected nephrolithiasis", section on 'Digital tomosynthesis' .)

Patients with asymptomatic stones  —  Some patients are found to have an asymptomatic kidney stone or stones by imaging performed for a different indication [ 34 ]. Approximately one-third of such patients will develop symptoms related to their kidney stones within three years, and as many as one-half of these symptomatic patients may require surgical treatment for their stones [ 35,36 ]. Thus, asymptomatic patients may benefit from a metabolic evaluation and appropriate medical therapy to prevent growth of any existing stones and to prevent new stone formation. We perform a complete metabolic evaluation in all asymptomatic patients who have multiple stones since we consider such patients to be recurrent stone formers. In addition, we perform a complete metabolic evaluation in select asymptomatic patients with a single stone, based upon their occupation (airline pilots, frequent business travelers), complexity (neurologic disease, anatomic abnormalities of the urinary tract, such as urinary diversion or solitary kidney), or the need for surgical stone removal. (See 'Complete metabolic evaluation' above.)

In asymptomatic patients with a single stone who do not warrant a complete metabolic evaluation, active surveillance with repeat imaging within one to two years (see 'Monitoring for new stones' above) is a reasonable approach. If repeat imaging shows no evidence of stone growth, imaging can be repeated every two years; if there is no stone growth after four to five years, active surveillance may be discontinued. If repeat imaging shows an increase in stone size or new stones, we perform a complete metabolic evaluation.

Several studies have examined the natural history of asymptomatic kidney stones. As examples:

● A cohort of 110 patients with 160 asymptomatic kidney stones was followed with active surveillance (using kidney ultrasound performed every 6 to 12 months) [ 35 ]. During a mean follow-up of 3.4 years, 28 percent of stones produced symptoms and 17 percent required surgery for these symptoms; an additional 3 percent caused silent obstruction that required intervention. Lower pole stones were less likely to cause symptoms or pass spontaneously.

● Another study monitored 107 such patients for a mean of 32 months [ 36 ]. The likelihood of developing symptoms was approximately 32 percent at 2.5 years and 49 percent at 5 years; the risk was lowest in patients who had no history of previous stones. Roughly one-half of symptomatic patients required a procedure (such as shock wave lithotripsy) for removal of the stone, while the remaining symptomatic patients passed the stone spontaneously.

In addition to these findings, a number of studies have determined that patients with residual stones following shock wave lithotripsy or percutaneous stone removal are at increased risk for symptomatic stone episodes. However, these investigations also suggest that appropriate medical stone management can significantly reduce recurrent stone formation or growth of existing stones [ 37-39 ].

SOCIETY GUIDELINE LINKS  —  Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Kidney stones" .)

SUMMARY AND RECOMMENDATIONS

● Goal of evaluation – In patients with established kidney stone disease, the goal of a diagnostic evaluation is to identify, as efficiently and economically as possible, the particular behavioral and physiologic differences present in a given patient so that effective therapy to prevent recurrent stones can be established and the prognosis can be better defined. (See 'Goal of evaluation' above.)

● Approach to evaluation – All patients presenting with established kidney stone disease should undergo a focused history, radiologic imaging, stone analysis (if available), and at least a limited laboratory evaluation:

• Focused history – The purpose of the focused history is to identify stone risk factors, such as a family history of stone disease and certain dietary habits ( table 1 ). (See 'Focused history for stone risk factors' above.)

• Radiologic testing – If not yet performed during the initial evaluation, radiographic examination, preferably with noncontrast, low-dose computed tomography (CT), should be obtained to search for residual stones within the urinary tract. Diagnostic tests for the detection of nephrolithiasis are discussed in detail elsewhere. (See "Kidney stones in adults: Diagnosis and acute management of suspected nephrolithiasis", section on 'Diagnostic imaging' .)

• Stone analysis – Analysis of the stone is an essential part of the evaluation. Patients should be encouraged to retrieve stones they pass spontaneously for analysis, although novel CT imaging techniques may permit noninvasive discrimination among the main subtypes of urinary calculi. Similarly, stones that are surgically removed should also be submitted for analysis. The most common crystalline materials found in kidney stones are calcium oxalate, calcium phosphate, uric acid, and struvite (magnesium ammonium phosphate). It is not uncommon for a stone to contain more than one crystalline component. (See 'Stone analysis' above.)

• Laboratory testing – Three options have been proposed for laboratory evaluation after a first stone: a limited evaluation, a complete metabolic evaluation, or a targeted approach. Although there is disagreement whether a complete metabolic evaluation should be performed after the first kidney stone, a complete metabolic evaluation is indicated in all patients with multiple stones at first presentation, patients with a strong family history of stones, patients with low bone mineral density, and individuals with active stone disease (defined as recurrent stone formation, enlargement of existing stones, or the recurrent passage of gravel). (See 'Approaches to laboratory testing' above.)

• Complete metabolic evaluation – The complete metabolic evaluation for nephrolithiasis consists of both blood and urine testing, including at least two 24-hour urine collections. In each 24-hour urine collection, the urine volume, pH, and excretion of calcium, uric acid, citrate, oxalate, sodium, potassium, magnesium, and creatinine (to assess the completeness of the collection) should be measured. Also, urinary supersaturation should be calculated. Urine collections should not be performed if there is evidence of kidney/ureteral obstruction from existing stones or urinary tract infection. (See 'Complete metabolic evaluation' above.)

● Monitoring for new stones – Radiologic monitoring, usually with ultrasonography; abdominal radiography; noncontrast, low-dose CT; or digital tomosynthesis, is warranted for the detection of new stones. Monitoring should be performed initially at one year and, if negative, every two to four years thereafter depending upon the severity of the stone disease and the 24-hour urine values. (See 'Monitoring for new stones' above.)

● Asymptomatic stones – Some patients are found to have an asymptomatic kidney stone or stones by imaging performed for a different indication. Such patients may also benefit from a metabolic evaluation and appropriate medical therapy to prevent growth of any existing stones and to prevent new stone formation. (See 'Patients with asymptomatic stones' above.)

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  • Liu S, Nie P, Wang H, et al. Application of Digital Tomosynthesis in the Diagnosis of Urolithiasis: Comparison with MDCT. J Endourol 2020; 34:145.
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Case Report: Not Just Another Kidney Stone

A 36-year-old woman with a history of nephrolithiasis presented to the ed for evaluation of increasing left flank pain and lightheadedness..

A 36-year-old woman with a history of nephrolithiasis presented with a chief complaint of increasing left flank pain and lightheadedness.

A 36-year-old woman with a 2-week history of left flank pain presented to the ED via emergency medical services. The patient, who had a history of nephrolithiasis, assumed her pain was due to another kidney stone. She stated that while waiting for the presumed stone to pass, the pain in her left flank worsened and she felt lightheaded and weak.

The patient’s vital signs at presentation were: heart rate, 96 beats/minute; blood pressure, 133/76 mm Hg; respiratory rate, 20 breaths/minute; and temperature, 98.9˚F. Oxygen saturation was 98% on room air. On physical examination, the patient had left lower quadrant pain and left costovertebral angle tenderness. Laboratory studies were remarkable for a negative urine pregnancy test, a hemoglobin level of 6.8 g/dL, and a hematocrit of 21.1%. Based on the patient’s history and symptoms, axial and coronal computed tomography (CT) scans were ordered, revealing a ruptured left renal calyx with hemorrhage from ureterolithiasis ( Figures 1a and 1b ).

case study on kidney stone

Rupture of renal calyx and extravasation of blood or urine is a potential complication of nephrolithiasis. Stone size, degree of obstruction, and length of symptomatic presentation presumably contribute to complications from nephrolithiasis. Stones that are symptomatic for more than 4 weeks are estimated to have an increased complication rate of up to 20%. 1

Calyx or fornix rupture results from increased intraluminal pressure. Rupture of these structures is thought to be a type of “safety-valve” function to relieve obstructive uropathy. 2

Obstructions from small leaks to large urinomas can cause extravasation of urine. In most cases, urinary extravasation is confined to the subcapsular space or perirenal space within the Gerota’s fascia; 3 however, as seen in this patient, mixed hematoma/urinomas can form.

In cases of nontraumatic calyx rupture, the cause of the obstruction is most often a distal obstructing ureteral stone. 4 Other causes of rupture include extrinsic compression from malignant and benign masses, ureteric junction obstructions, or iatrogenic causes. 4 Interestingly, in one small study, the median size of the obstructing stone was only 4 mm. The same study also noted that proximal ureteral obstruction occurred when larger stones where present. 4

Conservative Versus Nonconservative Management

Potential complications of urinomas include abscess formation, sepsis, hydronephrosis, and paralytic ileus. 3 Despite possible adverse sequelae, uncomplicated urinomas may be managed conservatively with supportive care. According to a study by Chapman et al, 5 about 40% of patients managed conservatively recover without complications. In addition, in a retrospective study by Doehn et al 6 involving 160 cases of fornix rupture treated with endoscopic therapy or nephrostomy tube supplemented with antibiotics, no instances of perinephric abscess or other complications requiring a second procedure were noted.

Management of suspected ureterolithiasis in the ED is focused on analgesia and supportive care. Acute analgesia is often provided parenterally with opioids alone or with an opioid/nonsteroidal anti-inflammatory drug (NSAID) combination. 7 Frequent reassessment of the patient is required to ensure adequate pain control and to prevent sedation. Other symptoms, such as nausea, vomiting, and dehydration, may be treated with intravenous (IV) fluids and antiemetic medications. Further radiographic evaluation is needed once analgesia is achieved. 7,8

Imaging Studies

Radiological evaluation of patients with suspected ureterolithiasis may involve several imaging modalities. Noncontrast helical CT scan is the standard for rapid and efficient identification of ureteral stones while allowing visualization of other potential pathology (eg, urinoma). 7-9 Other modalities, such as ultrasonography; radiography of the kidneys, ureters, and bladder; and an IV pyelogram with contrasted CT, may be ordered if noncontrast helical CT scan is not available on-site or if there are comorbidities. In addition to imaging studies, basic laboratory studies (eg, serum creatinine and blood urea nitrogen testing) are indicated to assess overall renal function and direct the choice of radiological study. 7

Disposition

Clinical decision-making is key when recommending inpatient versus outpatient treatment in patients with ureterolithiasis. Patients with uncontrolled pain or vomiting may require inpatient admission for supportive care, while those demonstrating acute renal failure, pyuria with bacteriuria, complete bilateral ureteral obstruction, urinoma, or signs of sepsis demand emergent urology consultation. Specifically, patients with urinoma require ureteroscopy versus nephrostomy 6,10 to allow drainage while carefully monitoring for development of subsequent bleeding and infection.

When discharging patients from the ED, expulsive therapy using tamsulosin 9 and analgesia with combination of oral opioids and NSAIDs are most commonly effective. 11 Outpatient urology referrals are recommended for ureteral stones greater than 5 mm in size or if the stones have been present in the ureter for greater than 4 weeks. 1 Proper evaluation and management of ureterolithiasis in the ED is crucial for positive outcomes and to reduce long-term complications.

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  • Published: 04 August 2020

Determining the true burden of kidney stone disease

  • Charat Thongprayoon   ORCID: orcid.org/0000-0002-8313-3604 1 ,
  • Amy E. Krambeck   ORCID: orcid.org/0000-0001-8255-598X 2 &
  • Andrew D. Rule 1 , 3  

Nature Reviews Nephrology volume  16 ,  pages 736–746 ( 2020 ) Cite this article

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  • Renal calculi
  • Risk factors

The incidence and prevalence of kidney stones have increased over the past four decades. However, the diagnosis of ‘kidney stone’ can range from an incidental asymptomatic finding of limited clinical significance to multiple painful episodes of ureteral obstruction with eventual kidney failure. Some general strategies may be useful to prevent the recurrence of kidney stones. In particular, greater attention to kidney stone classification, approaches to assessing the risk of recurrence and individualized prevention strategies may improve the clinical care of stone formers. Although there have been some advances in approaches to predicting the recurrence of kidney stones, notable challenges remain. Studies of kidney stone prevalence, incidence and recurrence have reported inconsistent findings, in part because of the lack of a standardized stone classification system. A kidney stone classification system based on practical and clinically useful measures of stone disease may help to improve both the study and clinical care of stone formers. Any future kidney stone classification system should be aimed at distinguishing asymptomatic from symptomatic stones, clinically diagnosed symptomatic stone episodes from self-reported symptomatic stone episodes, symptomatic stone episodes that are confirmed from those that are suspected, symptomatic recurrence from radiographic recurrence (that is, with radiographic evidence of a new stone, stone growth or stone disappearance from presumed passage) and determine stone composition based on mutually exclusive categories.

Kidney stones can range from an asymptomatic incidental finding with limited clinical significance to a painful recurrent disorder with substantial morbidity.

The prevalence and incidence of kidney stones has increased worldwide, but some of this increase is due to improvements in medical imaging with increased utilization of CT.

Classifying stone formers according to their clinical presentation and stone composition can help to predict the risk of future symptomatic stone episodes and aid personalization of stone prevention strategies.

The wide range of recurrence rates reported between different studies might largely be due to the use of different definitions that include various degrees of symptomatic evidence of recurrence and/or radiographic manifestations of recurrence.

Risk factors for symptomatic kidney stone recurrence include younger age, male gender, family history of stones, obesity, pregnancy, rarer stone compositions, higher radiographic kidney stone burden, number of past symptomatic kidney stone episodes and fewer years since last kidney stone episode.

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case study on kidney stone

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Recurrence of Kidney Stone (ROKS) tool: https://qxmd.com/calculate/calculator_438/roks-recurrence-of-kidney-stone-2018

A procedure for treating stones in the kidney or ureter using a high-energy shock wave from outside the body to break stones into fragments that are small enough to spontaneously pass in urine.

A procedure in which a small scope is inserted into the ureter via the urethra and bladder to diagnose and treat a variety of problems in the urinary tract. In the case of urinary stones, it allows the urologist to actually look into the ureter or kidney, find the stone and remove or fragment the stone.

A procedure used to remove kidney stones from the body when they cannot pass spontaneously.

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Thongprayoon, C., Krambeck, A.E. & Rule, A.D. Determining the true burden of kidney stone disease. Nat Rev Nephrol 16 , 736–746 (2020). https://doi.org/10.1038/s41581-020-0320-7

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Efficacy and safety of minimally invasive percutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of upper urinary tract stones (> 1 cm): a systematic review and meta-analysis of 18 randomized controlled trials

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Commentary on Calcium Kidney Stone Patient with Normocalcemia

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Larry A Broussard, Commentary on Calcium Kidney Stone Patient with Normocalcemia, The Journal of Applied Laboratory Medicine , 2024;, jfad136, https://doi.org/10.1093/jalm/jfad136

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This case study describes the workup, diagnosis, and successful treatment of a patient with a calcium kidney stone and a serum calcium concentration within the reference range. The investigation of the origin of the calcium stone included endocrine testing with the combination of low serum 25-OH vitamin D and elevated parathyroid hormone (PTH) levels indicating secondary hyperparathyroidism. After treatment with 25-OH vitamin D3, the 25-OH vitamin D levels increased but remained below the reference range lower limit and the PTH remained elevated. The calcium level now indicated hypercalcemia and the patient’s test results now matched the criteria for primary hyperparathyroidism (PHPT). The masking of the hypercalcemia by the secondary hyperparathyroidism complicated the initial diagnosis. Hyperparathyroidism was confirmed by scintigraphic confirmation of enlargement of the upper left parathyroid and surgical removal of this gland resulted in normal PTH and calcium concentrations.

Normocalcemic PHPT as seen in this case was first formally recognized in 2008 and the lack of consistency in diagnostic criteria still exists. In general, the diagnosis can be made with the combination of multiple occasions (at least 3 months apart) of elevated PTH levels with consistently normal total and ionized serum calcium. As mentioned in the case study and in an excellent review by Cusano and Cetani ( 1), the diagnosis of normocalcemic PHPT is a diagnosis of exclusion once secondary causes have been eliminated. The disease is relatively rare with an apparent prevalence of less than 1% but more epidemiological studies are needed to determine an accurate occurrence rate.

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Clinical Trials

Kidney stones.

Displaying 37 studies

Percutaneous nephrolithotomy (PCNL) is a surgical procedure that is standard of care for the removal of large kidney stones. PCNL involves removal of the stone(s) from the kidney through a temporary tract that is percutaneously placed through the patient's back during surgery. There is a significant risk of urinary tract infection after PCNL but wide clinical variation in use of prophylactic antibiotics in the days leading up to surgery. For patients who had already agreed to undergo PCNL, we plan to randomize them either to 1 week of preoperative antibiotic prophylaxis plus < 24 hours of perioperative IV antibiotics or ...

The primary focus of this minimal risk study will be to assess and refine the ability of DE CT to accurately determine kidney stone composition.

The purpose of the study is to compare the effects, good and/or bad, of a treatment for removing kidney stones called the SURE procedure for stone evacuation to the standard treatment using a basket for stone removal.

A prospective study to determine if the removal of non-obstructing renal calculi can reduce or eliminate participant's pain and/or improve their quality of life.

The purpose of this trial is to investigate the impact of increased fluid intake and increased urine output on the recurrence rate of urinary stone disease (USD) in adults and children. The primary aim of the trial is to determine whether a multi‐component program of behavioral interventions to increase fluid intake will result in reduced risk of stone disease progression over a 2‐year period.

The purpose of this study is to determine if the use of preoperative  antibiotics given to prevent infection actually decreases the postoperative risk in patients having surgery to remove kidney stones.

We hypothesize that clinical studies to investigate the role of individual proteins in kidney stone pathogenesis have likely been confounded by an unknown variety of underlying renal pathologies. Therefore, we propose to examine urinary protein crystallization inhibitors in patient populations that have been carefully phenotyped relative to renal stone precursor lesions by direct endoscopic visualization. In collaboration with Project #1, our second major goal is to use these accurately phenotyped patients in order to adapt modern dual-energy CT technology to develop a reliable noninvasive technique to accurately and noninvasively determine stone composition and visualize the earliest kidney stone precursor lesions. ...

90 genes related to Monogenic Stone Disease will be determined via DNA analysis by the Mayo Rare Kidney Stone Consortium (RKSC) research staff.

The purpose of this study is to determine if the performances of two types of scopes that are used to treat kidney stones are equivalent. This will help guide institutions in the future to purchase the best scopes for their patients.

The purpose of this study is to compare the operative outcomes and complications of mini-percutaneous nephrolithotomy (mini-PCNL) versus standard PCNL for renal stones.

The purpose of this study is to evaluate the potential of Moses laser technology to reduce operative time compared to non-Moses settings for ureteroscopic treatment of nephrolithiasis.

Assessment of Health-related Quality of Life in Rare Kidney Stone Formers in the Rare Kidney Stone Consortium

A Study of the ability for CT imaging to accurately predict the fragility (quality of being easily broken) of kidney stones during surgical intervention. 

The purpose of this study is to determine if models predicting symptomatic recurrence (Recurrence of Kidney Stones score) in  the prospective cohort study (IRB #08-006541) also predict radiographic stone formation and growth among 300 incident stone formers at Mayo Clinic Rochester and 55 incident stone formers at Mayo Clinic Florida in our current prospective cohort. 

In this study the investigators propose to use a daily dose of 45 mg (30 mg at 8 AM and 15 mg at 4 PM). This relatively small well-tolerated dose is likely to persistently increase urine volume and reduce urine supersaturation and to be well tolerated by patients with kidney stone disease and normal renal function. The twice-daily (8 AM and 4 PM) regimen is designed to produce a maximal AVP inhibition on waking with a gradual fall-off of effect during the night. To this end, a higher dose is used in the morning, with a lower dose in the ...

The purpose of this study is to assess the effectiveness of the Smart Water Bottle technology to monitor and increase fluid intake in patients with kidney stones and low urine output.

To characterize the microbiome in 4 groups of subjects (primary hyperoxaluria type I (PH1), idiopathic CaOx stone, enteric hyperoxaluria (EH) and healthy participants) by comparing the number of species and diversity of the microbial populations and pathway for oxalate metabolism by paralleling the gene expression of enzymes involved in oxalate degradation by gut bacteria.

The purpose of this study is to collect real-world evidence on the performance of the SOLTIVE™ Premium SuperPulsed Laser System for laser lithotripsy in ureteroscopy, PCNL or mini PCNL for kidney and ureteral stones.

Due to the ongoing opioid epidemic in the United States, there is increased attention and interest in reducing the use of opioid medication after surgery to minimize the risk of opioid tolerance and addiction, decrease the pool of unused opioids available for misuse, and maximize the use of alternative pain management medications and techniques. The purpose of this study is to implement and assess a standard way of prescribing opioids following percutaneous nephrolithotomy. 

The purpose of this study is to measure how well two different devices work to break up and remove kidney stones. We are comparing a newer device to an older one to see which one is faster at breaking up kidney stones. We hypothesize that the Trilogy device will increase the stone clearance rate by 25% compared to the Shockpulse-SE device.

Patients with Dent disease have suppressed levels of FGF 23 which contributes to hypercalciuria, kidney stones, nephrocalcinosis and renal failure. Supplementation with phosphorus may reduce hypercalciuria.

The purpose of this study is to establish a database to collect and analyze information on metabolic and environmental risk factors for kidney stone formation in children.

The purpose of this study is to compare the ability to identify uric acid renal stones between alternate CT scanning techniques and the current dual-source CT scanning technique.

The purpose of this study is to compare the frequency of occurance of kidney stone formation in liver disease patients compared to the general population.

The purpose of this study is to determine if CBD oil has any effect on decreasing postoperative pain control following ureteroscopy for urinary stone disease, and to determine if CBD oil has any effect in decreasing the amount of postoperative opioids (commonly used drug) used by patients after undergoing ureteroscopy for urinary stone disease.

By comparing people who have kidney stones to people who do not have kidney stones, we hope to learn what causes kidney stones to form and determine if kidney stones lead to loss of kidney function or kidney disease.

The objective of this study is to compare the effectiveness of (A) a standardized general risk information sheet only, (B) a standardized general risk information sheet plus a probabilistic risk tool, (C) standardized sheet plus narrative enhanced probabilistic risk tool on a variety of patient reported and patient centered outcomes related to pain treatment and the risks and benefits of opioid prescriptions for common, acute pain conditions.

The objective of this study is to collect data on stone formation and the degree of nephrocalcinosis in patients (≥ 2 years of age) with genetically confirmed PH3 and relatively intact renal function and to explore the potential relationship between Uox and new stone formation.

This is a natural history study of adults, adolescents, and children (≥ 2 years of age) with genetically confirmed primary hyperoxaluria type 3 (PH3) who have a history of stone events during the last 3 years and/or the presence of pre-existing stones detected by renal ultrasound at Screening.

The relationship between the level of Uox and the ...

This study will help us determine whether certain genetic mutations, more than others, are a cause of more severe disease in Primary Hyperoxaluria.

The purpose of this study is to collect medical information from a large number of patients in many areas of the world with primary hyperoxaluria (PH), Dent disease, Cystinuria and APRT deficiency. This information will create a registry that will help us to compare similarities and differences in patients and their symptoms. The more patients we are able to enter into the registry, the more we will be able to understand the Primary Hyperoxalurias,Dent disease, cystinuria and APRT and learn better ways of caring for patients with these diseases.

The purpose of this study is to evaluate the safety, tolerability, and effectiveness of different doses of ALLN 177 for reducing urinary oxalate excretion in patients with secondary hyperoxaluria and recurrent kidney stones.

Evaluate the safety, tolerability, and efficacy of 28 days of treatment with ALLN-177 for reducing urinary oxalate excretion in patients with secondary hyperoxaluria and kidney stones.

The purpose of this study is to determine the effectiveness, durability, and long-term safety of Reloxaliase in patients with Enteric Hyperoxaluria.

This study is being done to obtain samples from patients with primary hyperoxaluria, cystinuria, adenine phosphoribosyl transferase (APRT) deficiency, and Dent disease, and from their family members, for use in future research.

The purpose of this study is to obtain post-market safety and effectiveness data for FlexivaTM Pulse High Power Single-Use Laser Fibers during lithotripsy and soft tissue procedure of holmium laser enucleation of the prostate (HoLEP).

This study aims to evaluate the mechanisms leading to hyperoxaluria and increased risk of kidney stone formation after bariatric surgery.

The purpose of this study is to determine the natural history of the hereditary forms of nephrolithiasis and chronic kidney disease (CKD), primary hyperoxaluria (PH), cystinuria, Dent disease and adenine phosphoribosyltransferase deficiency (APRTd) and acquired enteric hyperoxaluria (EH). The investigator will measure blood and urinary markers of inflammation and determine relationship to the disease course. Cross-comparisons among the disorders will allow us to better evaluate mechanisms of renal dysfunction in these disorders.

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Kidney Stone Program

Like much of medicine, kidney stone disease is organized around a set of phenotypes, idiopathic calcium oxalate stone formers for example. A useful if medieval Platonic idealization, when looked at closely these phenotypes invariably disintegrate into what one might call medical atomism – the tyranny of the individual case.

When asked for an example of an idiopathic calcium oxalate stone former I never can find exactly the ‘perfect’ case but rather someone who fits well enough but with – how shall I put this? – rough edges, stray facts that do not fit the mold.

What this really means is obvious. Every physician practices ‘personalized medicine’ and, like most medieval intellectual conceptions, phenotypes have value more as metaphor than as a guide to the day’s work.

What it also means in that every patient is a node in the matrix of pathophysiology, clinical manifestations, and treatment complexities that make up this field, being a place in which all together give rise to the one single manifestation – crystal formation – which defines our work.

So I did not bring these cases, suitably disguised, from my precious museum but simply from recent outpatient sessions, as I find in almost every patient more or less a unique set of oddments that serve very well as special instances of general formulations – the reason cases are so important – concerning clinical evaluation, the technical business of pathophysiology, and the elaborate compromises of therapeutics. Every case is an ‘everyman’, and ‘everywoman’. You just have to look close and each one is a universe.

Ages are deliberately vague, dates for labs are presented from 0, the first one, upward in days or weeks or more. Occupations are similar but not the same as the real one – because people deserve privacy. Lab data, stone composition, rates of formation, treatments, and outcomes are rigorously exact.

Case 1: A Stone Former

As you will see, this is a person with considerable numbers of stone attacks who has certainly produced large stones in the past, but he posed major problems in deciding if stones were active and is therefore a perfect place to start. His many laboratory abnormalities are just wonderful for thinking about stone pathophysiology.

Case 3: A Success Story

This is a first for the site, and perhaps it should have been a feature long ago. After all the generalizations and reviews there is something wonderful about a single instance that contains all the elements of a topic in the kind of instructive detail we can get only in life itself. Pat – who has permitted me to use his name and data – forms calcium stones and has idiopathic hypercalciuria and a job that makes hydration a problem.

Case 5: Severe Hyperoxaluria

Severe hyperoxaluria – always worrisome, never something to dismiss or even wait a long time thinking about. The Vegetable Seller’ by Flemish painter Joachim Beuckelaer (c.1534-1574) seems a perfect image for this exercise in vegetable excess. He was never very famous but influential concerning food and kitchen scenes.  Jill Harris (pictured right) co-authored this article with me.  Kidney Stone History This 47 year old woman had her first manifest stone 12 years before I first met her.

Case 2: A Calcium Oxalate Stone Former

CLINICAL FINDINGS: A man in his fifties formed his first stone in the early 2000’s and his last 6 months ago. There was a single passage event a year or two after the first stone at which time he was given hydrochlorothiazide 25 mg daily.

Case 4: Medullary Sponge Kidney

Medullary sponge kidney (MSK) is more spoken about than witnessed, and more witnessed than accurately diagnosed. This patient adds to the 12 we have described in our publication, and adds also in having a very long and evolving history with one of us (FLC). We write for a general audience yet hope to include a level of detail that satisfies physicians and scientists. Here, we may fail of clarity to the one audience or of a sufficiency to the other because the disease is complex.

Case 6: Bariatric Surgery and Kidney Injury

Bariatric surgeries can injure kidneys by raising urine oxalate excretion. This latter causes kidney stones, and raises risk of acute and chronic oxalate nephropathy. Overall, their benefits far outweigh these risks, especially when patients and physicians take proper precautions.But risk lurks as if in shadows, and waits on accident. The patient here inadvertently raised her risk of injury. Like all instances this one is just that: Opportunity to inspect the details of an undesired outcome so as to reduce the chance it will happen to others.

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Kidney Stones Over the Years: A Survivor Shares His Story

Posted on: 30 Jul 2021

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Kim, a 75 year-old retired university professor, has lived with kidney stones for over 25 years.

In 1989, Kim had his first kidney stone surgery, shock wave lithotripsy (SWL). This was an old way to treat stones. It involved shock waves fired at his stones while he sat in a large tub of water. He says today’s SWL treatment is easier and more effective.

Many years later, in 2007, Kim was diagnosed with another kidney stone. This one was removed with ureteroscopy surgery (URS). In 2013, his stones returned. This time he needed a percutaneous nephrolithotomy (PCNL) surgery to treat a very large stone. It was almost the size of a baseball!

When Kim first heard about the surgery, he questioned how it would go. It involved making small cuts in his back, and inserting scopes into the center of his kidneys. Later, he said he was amazed at how smoothly the stones were removed.

Unfortunately, small pieces of stones still remain in Kim’s left kidney. Kim is now very careful about what he eats and drinks. He wishes he had known all along about how much your diet and fluids affect the way stones form. “I am much better educated today about how to prevent kidney stones,” says Kim. “I drink a lot of fluids and eat less salt and foods that form my type of stones. If I had some general education about stones and prevention 25 years ago, I would not have needed the care that I’ve had.”

Kim hopes his story will help the more than 1 million people diagnosed with kidney stones each year.

For more information on Kidney Stones, click here.  

Check out more survivor stories like Kim's on our Survivor Story home page.

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  • Patient Care & Health Information
  • Diseases & Conditions
  • Kidney stones

If your doctor suspects that you have a kidney stone, you may have diagnostic tests and procedures, such as:

  • Blood testing. Blood tests may reveal too much calcium or uric acid in your blood. Blood test results help monitor the health of your kidneys and may lead your doctor to check for other medical conditions.
  • Urine testing. The 24-hour urine collection test may show that you're excreting too many stone-forming minerals or too few stone-preventing substances. For this test, your doctor may request that you perform two urine collections over two consecutive days.

Imaging. Imaging tests may show kidney stones in your urinary tract. High-speed or dual energy computerized tomography (CT) may reveal even tiny stones. Simple abdominal X-rays are used less frequently because this kind of imaging test can miss small kidney stones.

Ultrasound, a noninvasive test that is quick and easy to perform, is another imaging option to diagnose kidney stones.

  • Analysis of passed stones. You may be asked to urinate through a strainer to catch stones that you pass. Lab analysis will reveal the makeup of your kidney stones. Your doctor uses this information to determine what's causing your kidney stones and to form a plan to prevent more kidney stones.
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Our caring team of Mayo Clinic experts can help you with your kidney stones-related health concerns Start Here

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Kidney stones care at Mayo Clinic

  • Computerized tomography (CT) urogram
  • Intravenous pyelogram

Treatment for kidney stones varies, depending on the type of stone and the cause.

Small stones with minimal symptoms

Most small kidney stones won't require invasive treatment. You may be able to pass a small stone by:

  • Drinking water. Drinking as much as 2 to 3 quarts (1.8 to 3.6 liters) a day will keep your urine dilute and may prevent stones from forming. Unless your doctor tells you otherwise, drink enough fluid — ideally mostly water — to produce clear or nearly clear urine.
  • Pain relievers. Passing a small stone can cause some discomfort. To relieve mild pain, your doctor may recommend pain relievers such as ibuprofen (Advil, Motrin IB, others) or naproxen sodium (Aleve).
  • Medical therapy. Your doctor may give you a medication to help pass your kidney stone. This type of medication, known as an alpha blocker, relaxes the muscles in your ureter, helping you pass the kidney stone more quickly and with less pain. Examples of alpha blockers include tamsulosin (Flomax) and the drug combination dutasteride and tamsulosin (Jalyn).

Large stones and those that cause symptoms

Parathyroid glands

Parathyroid glands

The parathyroid glands lie behind the thyroid. They produce parathyroid hormone, which plays a role in regulating the body's blood level of calcium and phosphorus.

Kidney stones that are too large to pass on their own or cause bleeding, kidney damage or ongoing urinary tract infections may require more-extensive treatment. Procedures may include:

Using sound waves to break up stones. For certain kidney stones — depending on size and location — your doctor may recommend a procedure called extracorporeal shock wave lithotripsy (ESWL).

ESWL uses sound waves to create strong vibrations (shock waves) that break the stones into tiny pieces that can be passed in your urine. The procedure lasts about 45 to 60 minutes and can cause moderate pain, so you may be under sedation or light anesthesia to make you comfortable.

ESWL can cause blood in the urine, bruising on the back or abdomen, bleeding around the kidney and other adjacent organs, and discomfort as the stone fragments pass through the urinary tract.

Surgery to remove very large stones in the kidney. A procedure called percutaneous nephrolithotomy (nef-row-lih-THOT-uh-me) involves surgically removing a kidney stone using small telescopes and instruments inserted through a small incision in your back.

You will receive general anesthesia during the surgery and be in the hospital for one to two days while you recover. Your doctor may recommend this surgery if ESWL is unsuccessful.

Using a scope to remove stones. To remove a smaller stone in your ureter or kidney, your doctor may pass a thin lighted tube (ureteroscope) equipped with a camera through your urethra and bladder to your ureter.

Once the stone is located, special tools can snare the stone or break it into pieces that will pass in your urine. Your doctor may then place a small tube (stent) in the ureter to relieve swelling and promote healing. You may need general or local anesthesia during this procedure.

Parathyroid gland surgery. Some calcium phosphate stones are caused by overactive parathyroid glands, which are located on the four corners of your thyroid gland, just below your Adam's apple. When these glands produce too much parathyroid hormone (hyperparathyroidism), your calcium levels can become too high and kidney stones may form as a result.

Hyperparathyroidism sometimes occurs when a small, benign tumor forms in one of your parathyroid glands or you develop another condition that leads these glands to produce more parathyroid hormone. Removing the growth from the gland stops the formation of kidney stones. Or your doctor may recommend treatment of the condition that's causing your parathyroid gland to overproduce the hormone.

Prevention of kidney stones may include a combination of lifestyle changes and medications.

Lifestyle changes

You may reduce your risk of kidney stones if you:

Drink water throughout the day. For people with a history of kidney stones, doctors usually recommend drinking enough fluids to pass about 2.1 quarts (2 liters) of urine a day. Your doctor may ask that you measure your urine output to make sure that you're drinking enough water.

If you live in a hot, dry climate or you exercise frequently, you may need to drink even more water to produce enough urine. If your urine is light and clear, you're likely drinking enough water.

  • Eat fewer oxalate-rich foods. If you tend to form calcium oxalate stones, your doctor may recommend restricting foods rich in oxalates. These include rhubarb, beets, okra, spinach, Swiss chard, sweet potatoes, nuts, tea, chocolate, black pepper and soy products.
  • Choose a diet low in salt and animal protein. Reduce the amount of salt you eat and choose nonanimal protein sources, such as legumes. Consider using a salt substitute, such as Mrs. Dash.

Continue eating calcium-rich foods, but use caution with calcium supplements. Calcium in food doesn't have an effect on your risk of kidney stones. Continue eating calcium-rich foods unless your doctor advises otherwise.

Ask your doctor before taking calcium supplements, as these have been linked to increased risk of kidney stones. You may reduce the risk by taking supplements with meals. Diets low in calcium can increase kidney stone formation in some people.

Ask your doctor for a referral to a dietitian who can help you develop an eating plan that reduces your risk of kidney stones.

Medications

Medications can control the amount of minerals and salts in the urine and may be helpful in people who form certain kinds of stones. The type of medication your doctor prescribes will depend on the kind of kidney stones you have. Here are some examples:

  • Calcium stones. To help prevent calcium stones from forming, your doctor may prescribe a thiazide diuretic or a phosphate-containing preparation.
  • Uric acid stones. Your doctor may prescribe allopurinol (Zyloprim, Aloprim) to reduce uric acid levels in your blood and urine and a medicine to keep your urine alkaline. In some cases, allopurinol and an alkalizing agent may dissolve the uric acid stones.
  • Struvite stones. To prevent struvite stones, your doctor may recommend strategies to keep your urine free of bacteria that cause infection, including drinking fluids to maintain good urine flow and frequent voiding. In rare cases long-term use of antibiotics in small or intermittent doses may help achieve this goal. For instance, your doctor may recommend an antibiotic before and for a while after surgery to treat your kidney stones.
  • Cystine stones. Along with suggesting a diet lower in salt and protein, your doctor may recommend that you drink more fluids so that you produce a lot more urine,. If that alone doesn't help, your doctor may also prescribe a medication that increases the solubility of cystine in your urine.
  • Percutaneous nephrolithotomy

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Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.

Preparing for your appointment

Small kidney stones that don't block your kidney or cause other problems can be treated by your family doctor. But if you have a large kidney stone and experience severe pain or kidney problems, your doctor may refer you to a doctor who treats problems in the urinary tract (urologist or nephrologist).

What you can do

To prepare for your appointment:

  • Ask if there's anything you need to do before your appointment, such as limit your diet.
  • Write down your symptoms, including any that seem unrelated to kidney stones.
  • Keep track of how much you drink and urinate during a 24-hour period.
  • Make a list of all medications, vitamins or other supplements that you take.
  • Take a family member or friend along, if possible, to help you remember what you discuss with your doctor.
  • Write down questions to ask your doctor.

For kidney stones, some basic questions include:

  • Do I have a kidney stone?
  • What size is the kidney stone?
  • Where is the kidney stone located?
  • What type of kidney stone do I have?
  • Will I need medication to treat my condition?
  • Will I need surgery or another procedure?
  • What's the chance that I'll develop another kidney stone?
  • How can I prevent kidney stones in the future?
  • I have other health conditions. How can I best manage them together?
  • Do I need to follow any restrictions?
  • Should I see a specialist? If so, does insurance typically cover the services of a specialist?
  • Is there a generic alternative to the medicine you're prescribing?
  • Do you have any educational material that I can take with me? What websites do you recommend?
  • Do I need a follow-up visit?

Besides the questions you prepare in advance, don't hesitate to ask any other questions during your appointment as they occur to you.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, such as:

  • When did your symptoms begin?
  • Have your symptoms been continuous or occasional?
  • How severe are your symptoms?
  • What, if anything, seems to improve your symptoms?
  • What, if anything, appears to worsen your symptoms?
  • Has anyone else in your family had kidney stones?
  • Goldman L, et al., eds. Nephrolithiasis. In: Goldman-Cecil Medicine. 26th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Jan. 20, 2020.
  • Kidney stones. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-stones. Accessed Jan. 20, 2020.
  • McKean SC, et al., eds. Kidney stones. In: Principles and Practice of Hospital Medicine. 2nd ed. McGraw-Hill Education; 2017. https://accessmedicine.mhmedical.com/. Accessed Jan. 20, 2020.
  • What are kidney stones? American Urological Association. https://www.urologyhealth.org/urologic-conditions/kidney-stones. Accessed Jan. 20, 2020.
  • Kellerman RD, et al. Nephrolithiasis. In: Conn's Current Therapy 2020. Elsevier; 2020. https://www.clinicalkey.com. Accessed Jan. 20, 2020.
  • Braswell-Pickering EA. Allscripts EPSi. Mayo Clinic. Nov. 3, 2021.
  • Curhan GC, et al. Diagnosis and acute management of suspected nephrolithiasis in adults. https://www.uptodate.com/search/contents. Accessed Jan. 20, 2020.
  • Yu ASL, et al., eds. Diagnostic kidney imaging. In: Brenner & Rector's The Kidney. 11th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Jan. 20, 2020.
  • Fontenelle LF, et al. Kidney stones: Treatment and prevention. American Family Physician. 2019. https://www.aafp.org/afp/2019/0415/p490.html. Accessed Jan. 20, 2020.
  • Preminger GM. Options in the management of renal and ureteral stones in adults. https://www.uptodate.com/search/contents. Accessed Jan. 20, 2020.
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Dr. Hu on future studies of transrectal vs transperineal prostate biopsy

“Our hope is to really change the practice of medicine,” says Jim C. Hu, MD, MPH.

In this video, Jim C. Hu, MD, MPH, shares secondary outcomes and future work based on the study, “Transperineal Versus Transrectal Magnetic Resonance Imaging–targeted and Systematic Prostate Biopsy to Prevent Infectious Complications: The PREVENT Randomized Trial.” Hu is a professor of urology at Weill Cornell Medicine / NewYork-Presbyterian Hospital in New York, New York.

Video Transcript:

In addition to expanding continued enrollment for first time biopsy, and I anticipate we'll hit that that enrollment target within the next 6 to 8 months, we'll do a re-analysis and see if there's statistical significance. We're also continuing to examine whether or not there's a difference in cancer detection rate, which I should mention was similar. That is, when we looked at detection of clinically significant prostate cancer, defined as grade group 2 or higher, we found that in the transperineal arm it was 53%, and in the transrectal arm it was 50%. So, those were very similar and didn't differ.

I should also note that [with] the transperineal biopsy and the transrectal biopsy, we asked men immediately and at 7 days after biopsy to rate the amount of pain, discomfort, and anxiety they experienced on a scale of 0 to 10, a numerical rating scale. Right after biopsy, men rated more pain and discomfort with the transperineal approach relative to the transrectal approach. In other words, for pain, for example, the difference was 3.6 vs 3.0 on that 0 to 10 scale. It was a smaller difference for discomfort, but that also reached statistical significance. But then when we reassessed at 7 days afterwards, through a patient reported survey, there were no differences in pain, discomfort, and anxiety and no difference in anxiety at the time of the procedure. So, there is a statistically significant difference in that transperineal approach had more pain and discomfort compared to transrectal. But then when we also look at the acute pain literature or publications in the past, they tend to say that a clinically meaningful difference is a score of 1.6 or higher, which again, that .6 difference didn't reach.

So, in other words, those are the secondary end points that we measured beyond biopsy-related infection, that is cancer detection, as well as pain and discomfort. Going back to your question about future studies, through a Patient Centered Outcomes Research Institute award, we're enrolling patients after they've had a previous biopsy to look at the infection rate. That is, men who had a previously negative biopsy or those on active surveillance. The reason for that is that there are some studies that suggest that in the setting of a prior biopsy, there is a higher risk of infection. We'll again look at secondary end points like pain and discomfort, as well as differences in cancer detection, which are still relevant given that, as I mentioned earlier, there are more people on active surveillance, and it would be interesting to see if there's any differences in cancer detection rate based on differing biopsy approaches. That's the work that's on deck for that. There's less men who undergo biopsy for active surveillance or prior negative biopsy indications, so that's going to take a little bit more time to enroll.

Ultimately, our goal is–with Andrew Vickers, PhD, who's one of the foremost prostate cancer biostatisticians in the world–we will pull data from these 2 large, randomized trials, along with others that have been done, and better define, using prospective high-quality data, what the true risk of biopsy-related infections is for men. Our hope is to really change the practice of medicine. If we find that both of these approaches are equivalent and safer than what's traditionally out there with a 5% to 7% risk of infection, then that would suggest to practicing urologists to adopt either the transperineal approach or targeted prophylaxis. Over time if we find with greater sample size that the risk of infection with transperineal biopsy is statistically lower, then that would give further evidence to give policymakers and/or CMS, the Centers for Medicare and Medicaid Services, some guidance in terms of giving us a separate CPT code for transperineal vs transrectal biopsy. I do think one of the barriers to greater adoption of transperineal biopsy is that in the office setting, not only is there a learning curve to learn and adopt a new approach to doing biopsy, but there's also increased costs, particularly when you use this disposable device called the precision point. Currently, both approaches are being captured with the same CPT code, and therefore being afforded the same reimbursement.

This transcription has been edited for clarity.

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The CELC-G-201 trial is assessing the safety, preliminary efficacy, and pharmacokinetics of gedatolisib plus darolutamide in mCRPC

Dr. Schwen on focal therapies for prostate cancer

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Zeyad Schwen, MD, a urologic oncologist at Cleveland Clinic, discusses how patient factors and cancer characteristics are key to deciding between focal therapies and whole gland treatment for prostate cancer.

As Patients Live Longer, New Criteria Needed for Prostate Cancer Trials

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Researchers sought to understand if a lack of cancer progression as monitored by radiography could substitute overall survival as a metric for metastatic prostate cancer clinical trials.

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Can drinking alkaline water help prevent kidney stones? Not likely, study finds

B ottled water marketed as "alkaline water" is unlikely to be an effective alternative for prevention of recurrent urinary stones, reports a study in the January issue of The Journal of Urology .

"While alkaline water products have a higher pH than regular water, they have a negligible alkali content—which suggests that they can't raise urine pH enough to affect the development of kidney and other urinary stones," comments senior author Roshan M. Patel, MD, of University of California, Irvine.

Alkaline water as alternative to prescription drugs for stone prevention?

Alkaline water, sometimes called high pH water, is an increasingly popular category of bottled water. Compared to tap water, with a typical pH around 7.5, alkaline water is manufactured to have a higher (more alkaline) pH—in the range of 8 to 10.

Consumption and sales of alkaline water have increased sharply in recent years. Proponents claim various health benefits, including improved hydration and increased urinary pH. Raising pH is a key strategy to prevent formation of certain types of urinary stones (uric acid or cystine) in patients with previous stones.

Potassium citrate tablets are commonly prescribed to prevent recurrent stones. However, many patients do not follow recommended treatment—often related to the need to take large pills several times per day. If alkaline water could raise urinary pH, it might be an attractive alternative for stone prevention.

To assess the potential for high pH water to prevent urinary stones, Dr. Patel's team measured the pH of five commercially available alkaline water products. They also reviewed published data on other types of drinks and over-the-counter products with the potential to raise urinary pH.

Despite higher pH, alkaline water has 'trivial' alkali content

The five brands tested in the study had a similar pH, in a narrow range around 10. One product contained a small amount of citrate, which was not listed on the product label. Otherwise, the tested alkaline waters had no organic anions that can be metabolized to alkali by the body—as supplied by potassium citrate tablets.

At a pH of 10, the tested products would have an alkali content of just 0.1 milliequivalent per liter (mEq/L). That's a "trivial" concentration compared to the body's typical metabolic acid production of 40 to 100 mEq/L per day, according to the authors.

In contrast, some other commercially available products do have the potential to increase pH—notably including orange juice, with an alkali content of up to 15 mEq/L. Orange juice also has the lowest estimated cost to achieve the target alkali concentration of 30 mEq per day.

Baking soda was among the most effective and cost-efficient alternatives, although with potential concerns related to sodium content. Newer products dissolvable in water also appeared to provide useful and affordable options. The article includes a graphic table comparing the alkali content of various products and their costs in reaching target alkali levels.

"Our findings may help to guide the selection of other treatments, including beverages and over-the-counter products, for preventing recurrent urinary stones," adds Dr. Patel. The researchers note the limitations of their laboratory study and emphasize the need for clinical trials of the options for raising urinary pH.

More information: Paul Piedras et al, Alkaline Water: Help or Hype for Uric Acid and Cystine Urolithiasis?, Journal of Urology (2024). DOI: 10.1097/JU.0000000000003767

The Urology Care Foundation offers information on kidney stone prevention .

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StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

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StatPearls [Internet].

Nephrolithiasis.

Leila Nojaba ; Nilmarie Guzman .

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Last Update: August 8, 2023 .

  • Continuing Education Activity

Nephrolithiasis is the term employed for kidney stones, also known as renal calculi, and they are crystal concretions formed typically in the kidney. Calculi typically form in the kidneys and ideally leave the body via the urethra without pain. Larger stones are painful and may need surgical intervention. This activity reviews the evaluation and treatment of nephrolithiasis and the role of the healthcare team in managing patients with this condition.

  • Review the risk factors for developing nephrolithiasis.
  • Explain the common physical exam findings associated with nephrolithiasis.
  • Outline common treatment options for nephrolithiasis.
  • Review the importance of improving care coordination amongst interprofessional team members to enhance the delivery of care for patients affected by nephrolithiasis.
  • Introduction

Nephrolithiasis, or kidney stones, is the most common condition affecting the urinary system, affecting about 12% of the world population, with a yearly incidence of 600,000 in America. It is the result of a crystal or crystalline concretion traveling from the kidney through the genitourinary system. [1] [2]  Kidney stones correlate with an increased risk of chronic kidney diseases, end-stage renal failure, cardiovascular diseases, diabetes, and hypertension. [3]

Most patients with nephrolithiasis form calcium stones (80%), most of which are composed primarily of calcium oxalate or calcium phosphate. The other main types include uric acid, struvite (magnesium ammonium phosphate), and cystine stones. Of note, one patient may have a stone that contains more than one type of crystal.

Risk Factors -  Influenced by certain diseases, habits, composition of urine. 

  • Personal history of prior kidney stones increases the risk of kidney stones  [4]  by 15% within the first year, and 50% within the next ten years. 
  • A family history of kidney stones increases the risk by 2.5 times. 
  • Increased enteric oxalate absorption, typically due to malabsorption, leads to increased formation of calcium oxalate crystals.  
  • Urinary tract infections altering urinary pH in the setting of urease-producing bacteria, producing struvite crystals
  • Low fluid intake  [5]
  • History of diabetes, obesity, gout, and hypertension  [6]
  • Acidic urine (pH< 5.5), which promotes uric acid formation in the setting of chronic diarrhea and gout
  • Epidemiology

The prevalence and recurrence rates of nephrolithiasis are increasing, with limited options of effective drugs and procedures, affecting about 12% of the population worldwide. The incidence is estimated at 600,000 in the U.S. Between the ages of 20 to 49; kidney stones affect men more frequently than in women (2 to 1). The lifetime recurrence rate is higher in males than in females. This fact is attributed to the increasing incidence of obesity due to poor dietary habits and lack of physical activity.

  • Pathophysiology

Renal stone formation involves physicochemical changes and urine supersaturation. In the setting of supersaturation, solutes precipitate in the urine leading to nucleation and crystal concretions. PH and specific concentrations of excess substances influence the transformation of a liquid to a solid. In respect to nephrolithiasis, supersaturation of stone-forming constituents like calcium, phosphorus, uric acid, oxalate, cystine, and low urine volume are risk factors for crystallization. [7]  Nephrolithiasis is preventable by avoiding supersaturation.

  • Histopathology

Urine microscopy is useful in analyzing the kidney stone if they are obtainable via urine straining. Below are the crystal formations typically associated with each stone type  [8] :

  • Calcium oxalate is the primary component of the majority of stones. They typically occur in the setting of hypercalciuria, hyperoxaluria, hypomagnesuria, hypercystinuria, hypocitraturia. 
  • Calcium phosphate: amorphous, wedge-shaped prisms in rosettes 
  • Also known as struvite stones, seen in infectious stones. In the setting of infections with bacteria that produce urease, such as Proteus mirabilis, Klebsiella pneumonia, Enterobacter, and Pseudomonas aeruginosa. The urease produces ammonia and CO2, which creates basic pH urine (>7) .      
  • These stones are typically idiopathic. They occur in patients whose diets are high in protein, which acidifies urines pH (<7), allowing for uric acid stone formation.
  • These stones are caused by a genetic defect in the transport of the amino acid cystine, resulting in hypercystinuria.
  • History and Physical

Patients with nephrolithiasis, when limited to the kidney, will be asymptomatic. The common symptoms associated with kidney stones, including acute pain radiating to the groin, occurs once the stone begins descending the ureters from the kidneys. It is often described as dull, colicky, sharp, and severe pain.  The pain is often associated with nausea and vomiting due to the severity of pain. These symptoms are attributed to the peristalsis of the genitourinary tract smooth muscle against the stone. Hematuria is commonly reported as well, due to the injury against the genitourinary tract secondary to the stone; this is confirmable via urinalysis. 

If the stone becomes infected, patients may develop fever, chills, or other signs of worsening systemic signs of infection (i.e., shock). The physical exam may reveal costovertebral tenderness.  Obstruction can occur, and pyelonephritis with concurrent hydronephrosis can result. This situation can be severe and life-threatening, requiring emergency decompression surgery.

Laboratory tests to assess renal function, including either a basic or comprehensive metabolic panel, may be used. Additionally, a urinalysis, urine electrolytes, and urine pH can help direct towards a specific type of stone. 

A KUB (kidney-ureter-bladder) X-ray is also an option; however, uric acid stones are difficult to assess with this imaging. A CT of the abdomen and pelvis without contrast can also be performed and has higher sensitivity. Contrast medium is typically avoided when there is a concern for a kidney stone as enhancement of the vessels and ureters can obscure stone findings. 

  • Treatment / Management

Kidney stones are extremely painful. Pain control is of utmost importance with NSAIDs by decreasing smooth muscle stimulation and ureteral spasm. Additionally, it is essential to increase fluid intake. Tamsulosin, may also aid stone passage, and also reduces smooth muscle stimulation. It is typically useful in those in the distal ureter and sizes between 5 to 10 mm.  

Stones greater than 6mm are likely to require some intervention, including percutaneous nephrolithotomy, rigid and flexible ureteroscopy, and shock wave lithotripsy. [9]

  • Differential Diagnosis

Conditions listed below may mimic nephrolithiasis-induced flank pain:

  • Pyelonephritis, which typically presents with pyuria, fevers, chills and flank pain
  • Ovarian cyst torsion
  • Ectopic pregnancies 
  • Intestinal associated diseases, including obstruction, appendicitis, and diverticulitis
  • Cholecystitis, hepatitis, and biliary colic 
  • Herpes zoster 
  • Narcotic-seeking individuals 
  • Renal cell carcinomas

Kidney stones that do not pass can become obstructive and can subsequently cause acute renal failure, or it can also become a nidus for infection, which can eventually be lethal. If the patient undergoes nephrostomy tube placement, then there is a chance of bleeding, renal collecting system injury, injury of visceral organs, pulmonary complications, thromboembolic complications, and extrarenal stone migration. [10]

  • Complications

Several complications can arise due to kidney stones, and subsequently, stones that cause obstruction. These include:

  • Abscess formation
  • Urinary fistula formation
  • Ureteral scarring and stenosis
  • Ureteral perforation
  • Renal function loss due to long-standing obstruction
  • Consultations

Failure of stone passage within a month warrants a urology consultation.

Indications for hospitalization and urgent urology consultation and intervention are:

  • An obstructed and infected upper urinary system
  • Intractable vomiting or pain
  • Anuria or deteriorating renal function
  • History of transplanted kidney or solitary kidney with obstructing stone 
  • Deterrence and Patient Education

Identification and Subsequent Prevention

Effective kidney stone prevention depends on stone identification. Implementing preventive strategies that include primarily dietary changes and/or pharmacological treatments may be required. Additionally, regardless of underlying etiology, increasing water intake to maintain two liters of urine output per day, a low salt diet, and a decreased amount of animal protein consumption should be a daily practice. For absorptive hyperoxaluria, a low oxalate diet and increased dietary calcium intake are both recommended. Calcium supplements can reduce oxalate absorption, and can be protective. For struvite stones, patients must receive careful follow-up until the infection has resolved. [11]

  • Enhancing Healthcare Team Outcomes

Nephrolithiasis frequently poses a prevention and treatment dilemma. These patients may exhibit non-specific signs and symptoms such as abdominal pain, nausea, and urinating difficulties. Knowledge of the stone type can point the patient to changes in lifestyle habits that would prevent further stone formations. Patient adherence, along with detailed lifestyle changes, should be discussed between the patients, primary physician, and the urologist. Recurrent stone formation can exacerbate worsening renal function, especially in those with a history of end-stage renal disease. If given medication as treatment or prevention, it is also just as necessary for the pharmacist to recognize the use of the medication and further counsel patients on lifestyle habit changes. 

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Nephrolithiasis on ultrasound: normal kidney; grades of hydronephrosis; twinkle artifact; UVJ stone Contributed by Meghan K. Herbst, MD

Disclosure: Leila Nojaba declares no relevant financial relationships with ineligible companies.

Disclosure: Nilmarie Guzman declares no relevant financial relationships with ineligible companies.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

  • Cite this Page Nojaba L, Guzman N. Nephrolithiasis. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

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COMMENTS

  1. Urolithiasis presenting as right flank pain: a case report

    Case study. History. ... The majority of kidney stones contain calcium (approximately 90% in men and 70% in women) while the remainder consist of cystine (<1%), pure uric acid (10-15%) and struvite (10-15%). 7 Calcium based stones are most commonly composed of calcium oxalate, calcium phosphate or both. Several factors can affect stone ...

  2. Kidney stones in adults: Evaluation of the patient with ...

    Several studies have examined the natural history of asymptomatic kidney stones. As examples: A cohort of 110 patients with 160 asymptomatic kidney stones was followed with active surveillance (using kidney ultrasound performed every 6 to 12 months) . During a mean follow-up of 3.4 years, 28 percent of stones produced symptoms and 17 percent ...

  3. Case Report: Not Just Another Kidney Stone

    Case. A 36-year-old woman with a 2-week history of left flank pain presented to the ED via emergency medical services. The patient, who had a history of nephrolithiasis, assumed her pain was due to another kidney stone. She stated that while waiting for the presumed stone to pass, the pain in her left flank worsened and she felt lightheaded and ...

  4. PDF Challenging Cases in Kidney Stone Disease: The Multidisciplinary Approach

    Challenging Cases in Kidney Stone Disease: The Multidisciplinary Approach Floyd A. Fried Advances in Urology Symposium ... Case 1 • Trial of stone passage with flomax • Repeat KUB at 3 weeks shows stone ... Case 5 • 24-hour urine study: • Recommended indapamide 2.5 mg daily, low salt diet, continued good fluid intake .

  5. Treatment of a patient with total urinary calculi: a case report

    Urinary tract stones are a general term for stone disease in various parts of the urinary system and are common diseases of the urinary system. According to the location of the stone, it is divided into kidney stones, ureteral stones, bladder stones, urethra stones. Total urinary calculi occur less frequently, usually accompanied by severe ...

  6. Kidney Stone Disease: An Update on Current Concepts

    Kidney stone disease is a crystal concretion formed usually within the kidneys. It is an increasing urological disorder of human health, affecting about 12% of the world population. It has been associated with an increased risk of end-stage renal failure. The etiology of kidney stone is multifactorial. The most common type of kidney stone is ...

  7. Calcium Kidney Stone Patient with Normocalcemia

    A case study of a normocalcemic calcium kidney stone patient is presented due to a combination of primary and secondary hyperparathyroidism. The primary hyperparathyroidism diagnosis was consistent with our patient's hypercalcemia, increased PTH, and serum 25-OH vitamin D above 50 nmol/L during substitution therapy.

  8. Determining the true burden of kidney stone disease

    In a community-based study of 293 patients with asymptomatic kidney stones in China (mean diameter of 4.7 mm) detected by ultrasound during health screening, 60% had stone-related events, defined ...

  9. Educational Case: Urinary Stones

    Although a 24-hour urine study provides valuable information regarding the contents of a patient's urine and their metabolic status, it does not substitute for stone analysis. Per the most recent AUA guideline for the medical management of kidney stones, when a stone is available, it should be sent for analysis. 16

  10. (PDF) Renal Calculi: An Evidence Based Case Study

    The primary components of the majority of kidney stones are calcium salts, uric acid, cystine, and struvite. 2 The incidence of urolithiasis is a significant financial burden on the healthcare ...

  11. Commentary on Calcium Kidney Stone Patient with Normocalcemia

    This case study describes the workup, diagnosis, and successful treatment of a patient with a calcium kidney stone and a serum calcium concentration within the reference range. The investigation of the origin of the calcium stone included endocrine testing with the combination of low serum 25-OH vitamin D and elevated parathyroid hormone (PTH ...

  12. Calcium Kidney Stones

    Diagnosis of a calcium stone requires analysis after passage or removal of the stone. After passage of a first stone, the risk of recurrence is 40% at 5 years and 75% at 20 years. Among patients ...

  13. PDF Kidney stones: pathophysiology, diagnosis and management

    Kidney stones: pathophysiology, diagnosis and management. A case study approach. Abstract The prevalence of kidney stones is increasing, and approximately 12,000 hospital admissions every year are due to this condition. This article will use a case study to focus on a patient diagnosed with a calcium oxalate kidney stone.

  14. Kidney Stones Clinical Trials

    The purpose of this study is to determine if models predicting symptomatic recurrence (Recurrence of Kidney Stones score) in the prospective cohort study (IRB #08-006541) also predict radiographic stone formation and growth among 300 incident stone formers at Mayo Clinic Rochester and 55 incident stone formers at Mayo Clinic Florida in our ...

  15. CASE 1: A stone Former

    This case then highlights an important point of practice. It is futile to look for 'normal ranges' for supersaturations, as normal and stone forming patients have overlapping values - or can. Unfortunately i n his brilliant studies of urine stone risk, Curhan did not publish supersaturations, so we cannot link them stone stone risk in ...

  16. Educational Case: Urinary Stones

    sound or abdominal (kidney-ureter-bladder, KUB) radiograph may be used. However, operator experience may affect ultrasound results; and some stones are radiolucent on a KUB radiograph. Additional studies such as serum uric acid, para-thyroid hormone, and 25-hydroxy vitamin D may be needed based on the results of these initial studies.

  17. Nutrition and Kidney Stone Disease

    A case-control study of 186 calcium oxalate stone patients found a significant positive association between dietary ascorbic acid intake and urinary oxalate excretion . The association between ascorbic acid intake and the risk of urinary stone formation has been noted in several large cohort studies [ 146 , 147 ].

  18. Cases

    Case 1: A Stone Former. As you will see, this is a person with considerable numbers of stone attacks who has certainly produced large stones in the past, but he posed major problems in deciding if stones were active and is therefore a perfect place to start. His many laboratory abnormalities are just wonderful for thinking about stone ...

  19. PDF Kidney Stones: Diagnosis, Treatment, & Future Prevention

    References ARUPConsult.com UpToDate.com Coe F, Parks J, Asplin J. The pathogenesis and treatment of kidney stones. New Eng J Med 1992;327:1141-1151 Daudon M, Marfisi C, Lacour B, Bader C. Investigation of urinary crystals by Fourier Transform Infrared Microscopy. Clin Chem 1991; 37:83.87. Jager P. Genetic versus environmental factors in renal stone disease.

  20. Kidney Stones: Report of Case

    X-ray examination on April 4, 1924, showed the condition seen in Figure 1—a much enlarged right kidney almost completely filled with overlapping masses of stones, arranged in two groups, that in the upper pole being somewhat smaller. No stones were seen in the ureters or the left kidney. Operation was performed one year after the initial X ...

  21. Kidney Stones Over the Years: A Survivor Shares His Story

    Kim, a 75 year-old retired university professor, has lived with kidney stones for over 25 years. In 1989, Kim had his first kidney stone surgery, shock wave lithotripsy (SWL). This was an old way to treat stones. It involved shock waves fired at his stones while he sat in a large tub of water.

  22. Case Study on Kidney Stones

    Evidence based information: A case study Introduction Kidney stone disease also known as nephrolithiasis is a disease where there are hard deposits made of salt and minerals that form inside the kidney (Tang & Lieske, 2015). Some of the causes of kidney stones include certain medications, supplements, excess body weight, diet, and some medical ...

  23. Kidney stones

    Drinking as much as 2 to 3 quarts (1.8 to 3.6 liters) a day will keep your urine dilute and may prevent stones from forming. Unless your doctor tells you otherwise, drink enough fluid — ideally mostly water — to produce clear or nearly clear urine. Pain relievers. Passing a small stone can cause some discomfort.

  24. Recent advances on the mechanisms of kidney stone formation (Review)

    1. Introduction. Kidney stone disease, also known as nephrolithiasis or urolithiasis, is one of the oldest diseases known to medicine. It is estimated that 1-15% individuals suffer from kidney stone formation at some point during their lifetime, and the prevalence and incidence of kidney stone is reported to be increasing worldwide (1,2).A recent study concluded that the prevalence of kidney ...

  25. Dr. Hu on future studies of transrectal vs transperineal prostate biopsy

    In this video, Jim C. Hu, MD, MPH, shares secondary outcomes and future work based on the study, "Transperineal Versus Transrectal Magnetic Resonance Imaging-targeted and Systematic Prostate Biopsy to Prevent Infectious Complications: The PREVENT Randomized Trial." Hu is a professor of urology at Weill Cornell Medicine / NewYork-Presbyterian Hospital in New York, New York.

  26. Can drinking alkaline water help prevent kidney stones? Not likely

    Bottled water marketed as "alkaline water" is unlikely to be an effective alternative for prevention of recurrent urinary stones, reports a study in the January issue of The Journal of Urology.

  27. Applied Sciences

    To attain precise forecasts of surface displacements and deformations in goaf areas (a void or cavity that remains underground after the extraction of mineral resources) following coal extraction, this study based on the limitations of individual time function models, conducted a thorough analysis of how the parameters of the model impact subsidence curves. Parameter estimation was conducted ...

  28. Nephrolithiasis

    Nephrolithiasis, or kidney stones, is the most common condition affecting the urinary system, affecting about 12% of the world population, with a yearly incidence of 600,000 in America. It is the result of a crystal or crystalline concretion traveling from the kidney through the genitourinary system.[1][2] Kidney stones correlate with an increased risk of chronic kidney diseases, end-stage ...

  29. CVM researchers receive grant to study why kidney stones form in cats

    College of Veterinary Medicine researchers led by Dr. Jody Lulich received start-up funds from the EveryCat Health Foundation to study the formation of kidney and ureteral stones in cats. Ureters are the tubes carrying urine from the kidneys into the bladder. When stones obstruct the ureter, they cause severe kidney damage and thus pose a significant health threat.