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Kidney Stone

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Other Names

  • Kidney Stone
  • Renal calculus
  • Nephrolithiasis
  • Urolithiasis
  • Renal stone
  • Urinary calculus
  • Urinary stone
  • Calculus of the kidney
  • Renal lithiasis
  • Kidney calculus
  • Stone in the kidney
  • Urolithiasis

Background

  • This page refers to Kidney Stones

History

  • Needs to be updated

Epidemiology

  • Approximately 11–16% of men and 7–8% of women will experience symptoms from urolithiasis by age 70[1]
  • Average age is between 20 and 50 years[2]
  • Recurrence rate approaches 50% over 10 years[3]

Introduction

a Schematic presentation of the urinary system in the human body; b cross-section of a kidney with stones; and c mechanisms of the kidney stone formation from Evan (2010): (1) free particle formation in the calyceal pelvis system, and the fixed particle model, (2) the development intratubular calcification in the nephron* that subsequently leads the formation of the nephrolithiasis adhere to the apical surface of the tubular epithelium called duct of Bellini, and (3) Randall's plaque formation is triggered in the interstitial basement membrane in the loop of Henle, then the plaque grows and comes into contact with the urine in the calyx system[4]
Kidney stone locations in the urinary system[5]
Stages of kidney stone formation[6]

General

  • Kidney stones are a common cause of back, flank, abdominal and groin pain
  • In athletes, kidney stones are primarily linked to dehydration and low urine volume
  • The diagnosis is made with urinalysis and imaging modalities
  • Treatment is non-surgical in many cases, but there are indications for surgical management

Terminology

  • Nephrolithiasis: stones within the kidney
  • Ureterolithiasis: stone swithin the ureter
  • Urolithiasis: stones within the kidneys, ureters, bladder, or urethra

Pathophysiology

  • Predominantly due to an imbalance of urinary solute and solvent
  • Solutes normally dissolve in a solution until a specific saturation point
  • Once the saturation point is exceeded, stones can form in the urine
  • Citrate, glycoproteins, and magnesium inhibit crystal formation, while other materials, referred to as ‘nucleating centers’ (eg, epithelial cells, urinary casts, and red blood cells), form areas for crystal collection[7]
  • Nucleating centers accelerate crystal growth and coalesce into larger centers
  • Urinary pH, both acidotic and alkaline, can influence stone formation
  • Calcium stones represent 80% of kidney stones and include a mixture of solutes[8]
  • Hypercalciuria, hyperuricosuria, hypocitraturia, hyperoxaluria, and urinary pH abnormalities are risk factors for stone formation
  • Diets with high salt, high protein, or low calcium content also increase the risk of urolithiasis

Kidney Stones in Athletes

  • Dehydration is a key risk factor for stone formation in athletes[9]
  • Vigorous physical activity (VPA) itself may increase kidney stone risk, especially at high durations[10]
  • The overall effect of exercise on kidney stone risk remains equivocal.[11]

Pathoanatomy

  • In the kidney, stones can form in the parenchyma, calyx, pelvis, or ureter[12]
  • Once there, size and location have the greatest influence on symptoms and management
  • Likelihood of stone passage relates to location, size, shape, and degree of ureteral obstruction
  • Three areas of decreased luminal diameter[13]
    • The ureteropelvic junction
    • The site where the ureter crosses the iliac vessels
    • The area where the ureter meets the bladder wall and emerges in the ureteral orifice
  • These sites may result in stone impaction, obstruction

Risk Factors

  • Men more commonly than women roughly 2:1[14]
  • Obesity
  • Decreased fluid intake
  • Increasing age
  • Caucasian race
  • Lower socioeconomic status
  • Diabetes Mellitus
  • Gout

Differential Diagnosis

Urinary/ Reproductive Tract

Gastrointestinal and abdominal issues

  • Appendicitis
  • Diverticulitis
  • Gallstones
  • Pancreatitis
  • Cholecystitis (inflammation of the gallbladder)
  • Mesenteric ischemia (insufficient blood flow to the intestines)
  • Intestinal obstruction
  • Irritable Bowel Syndrome (IBS)

Musculoskeletal issues

  • Musculoskeletal pain in the back, flank, or abdomen

Other

  • Vascular
  • Abdominal aortic aneurysm

Clinical Features

History

  • The most common symptoms are flank pain hematuria, nausea, vomiting[15]
  • Pain nature and location often changes based on the stone location[16]
    • Specific stone location does not necessarily directly correlate with location of pain
  • Pain is typically waxing and waning
  • It can become more constant, which might suggest a complete obstruction
  • Intermittent pain is more commonly associated with an incomplete obstruction
  • Patients may feel pain in the intestines, groin, bladder, or genitalia[17]
  • Ipsilateral genital pain is a common location for referred pain with distal ureteral stone
  • Symptoms associated with urinary tract infection are common
    • This includes urgency, dysuria, frequency, and pain at the urethral meatus
  • Once stones have passed into the bladder, they may become asymptomatic
  • Fever, chills and rigors are uncommon in uncomplicated urolithiasis and should raise concerns for an infected stone

Physical Exam: Physical Exam Abdomen

  • Classically unable to find a comfortable position
  • Tachycardia and hypertension may be present due to pain
  • Costovertebral angle tenderness is present in 25-52% of patients and is often severe[18]
  • Abdominal exam is usually soft, non tender and non-distended
  • Less commonly, guarding (61%), rebound tenderness (29%), and rigidity (8%) can be present
  • Evaluation of the genitalia and groin should be normal

Evaluation

The color Doppler study shows twinkling artifact posterior to the hyperechoic foci suggesting it is a calculus. Color Doppler shows a continuous slow ureteric jet on the right side in comparison with the intermittent ureteric jet on the left side[19]
Grades of hydronephrosis[20]
KUB radiograph shows multiple calculi in the left mid and distal ureter
CT scan of the abdomen and pelvis showing a renal stone in the lower pole of the right kidney with mild hydronephrosis and fullness of the right renal pelvis.[21]

Radiographs

  • KUB Radiographs may be useful[22]
  • Majority of calcium-containing stones are visible on x-ray
  • Certain stone compositions (eg, cystine and uric acid stones) are radiolucent and not identifiable on x-ray
  • Other limitations: overlying bowel gas, patient body habitus, and extra-renal calcification
  • Sensitivity 59%, specificity 71%[23]
  • Does not evaluate for hydronephrosis, specific stone location

Computed Tomography (CT)

  • Considered the gold standard imaging modality for most patients with acute urolithiasis
  • Sensitivity and specificity are 98-100% regardless of size, composition[24]
  • Also extraordinarily useful to evaluate for other painful conditions
  • Low dose CT imaging reduces radiation exposure, maintains similar diagnostic accuracy[25]
    • Less accurate when detecting small stones or in patients with BMI over 30
  • Historically, avoidance of IV contrast was recommended to improve visualization[26][27]
    • IV contrast may be needed for concomitant evaluation of alternate etiologies for the patient's symptoms
    • Two studies suggest diagnostic accuracy 97-100% for stones > 2 mm

Ultrasound

  • Advantages: cheap, no radiation, can be performed at bedside
  • The presence of stone is often indirectly assessed by hydronephrosis
    • Note that 11–15% of patients with urolithiasis may not have hydronephrosis on examination[28]
    • Degree of hydronephrosis seems to correlate with stone size
    • Absence of hydronephrosis associated with a significantly decreased rate of urologic interventions[29]
  • Stones can be directly visualized, appearing as hyperechoic lines with posterior acoustic shadowing
  • Twinkling sign: appearance of alternating colors located deep to the stone
    • Highly specific for the presence of a kidney stone[30]
  • Overall sensitivity 54-57%, 91-98% specific[31]
    • Some societies now recommend US as the initial imaging modality of choice, others recommend CT

MRI

  • Not commonly used in the evaluate of acute urolithiasis
  • useful for the identification of urolithiasis in pregnant patients when ultrasound is non-diagnostic
  • 93% accurate, and similar to ultrasound, does not require any ionizing radiation

Laboratory

  • Urinarlysis
    • Urinary crystals are common in normal patients, should not be used for diagnosis
    • The presence of white blood cells (WBCs), leukocyte esterase, and nitrites can suggest urinary tract infection (UTI)
    • Approximately 8% of all patients with suspected urolithiasis experience concomitant UTI, diagnosed by urinary culture[32]
  • Hematuria
    • Hematuria is most commonly microscopic, though it can be macroscopic
    • Up to 90% of cases have microscopic hematuria
    • Hematuria has a diagnostic accuracy if only 60%
    • The absence of hematuria does not exclude a kidney stone
    • Sensitivity is as high as 95% on the first day of symptoms but decreases to 65% by day 3[33]
    • Though 85-90% of patients experience some form of hematuria, 25% of patints with hematuria and flank pain do not have radiologic evidence of urolithiasis[34]
  • Renal function on metabolic panel[35]
    • Patients may present with slight changes in creatinine clearance, rarely severe enough to qualify as an acute kidney injury
    • More severe creatinine elevation may be found in patients with a solitary kidney or baseline CKD
    • The most common cause is due to dehydration from nausea and vomiting
  • Metabolic evaluation in the outpatient setting
    • Not necessarily indicated for a single urolithiasis
    • For serology, consider: Serum calcium, phosphorus, magnesium, oxalate, sulfate, citrate, ammonium, cysteine, vitamin D levels, lactate dehydrogenase, and parathyroid hormone
    • For urinalysis, consider: urine electrolytes, uric acid, pH, calcium, and creatinine

Classification

STONE Scoring Tool[36]

  • Useful to stratify risk of kidney stone
    • Low probablity: 0-5 (9%)
    • Mod probability: 6-9 (51%)
    • High probability: 10-13 (89%)
  • Criteria
    • Sex: Female (0), Male (2)
    • Timing: > 24 hours (0), 6-24 hours (1), <6 hours (3)
    • Origin: Black (0), Non-Blak (3)
    • Nausea: None (0), Nausea (1), Vomiting (2)
    • Hematuria: Absent (0), Present (3)

Management

Treatment algorithm for urolithiasis[37]
X-ray (AP view) showing the double-J stent marked as S and the stone is shown with arrow. Left and right sides are marked as 'L' and 'R' respectively.[38]

Medical Management

  • Immediate analgesia for this painful condition
    • Consider opiates, INSAIDS (IV Ketorolac), Corticosteroids (IV Dexamethasone)
    • IV lidocaine has shown mixed results in the literature
  • Tamsulosin[39]
    • Helps with stone passage rate, decreased analgesic requirement, lower rates of hospitalization
  • IV Fluids[40]
    • Theorized to help with increasing urinary flow, pushing the stone through the ureter
    • Evidence does not suggest it helps with expulsion or pain scores

Surgical Management

  • Indications
    • Depends upon stone size, duration of symptoms, and modifying factors (eg, solitary kidney, renal transplant, renal dysfunction, associated pyelonephritis, refractory pain)
    • Spontaneous passage rate: 1-mm stones (87%), 2-to-4-mm (76%), 5-to-7-mm (60%), 7-to-9-mm (48%), >9-mm (25%)[41]
    • Stone location also correlates with rate of spontaneous passage
  • Definitely indicated if stone > 15 mm or fail to pass spontaneously with medical management alone
    • Technique
    • Lithotripsy
    • Ureteroscopic removal
    • Percutaneous nephrolithotomy

Disposition

  • Many patients in the ED can be discharged
    • Uncomplicated urolithiasis, are able to take fluids bymouth, not toxic appearing, and have pain adequately controlled
  • Some patients in the ED will require admission
    • Including intractable pain, vomiting, sepsis, single kidney, transplant kidney, acute renal failre, severe comorbidities, etc
  • Patients with first episode of urolithiasis can follow up with primary care provider
  • Indications for urology follow up
    • Stones ≥ 5 mm
    • Recurrent episodes of urolithiasis

Prevention

  • 50% of patients with urolithiasis will have recurrence within 10 years[42]
  • Hydration is critical[43]
    • Fluid intake should be increased to maintain urine output >2–2.5 L/day
    • Especially during intense training or heat exposure
  • Dietary assessment and modification are essential[44]
    • Including normal calcium intake, reduced sodium and animal protein, and increased fruits/vegetables
    • Tailored to stone type and metabolic findings
  • Pharmacotherapy[45]
    • In select cases for recurrent or high risk patients
    • Includes thiazide diuretics, citrate

Rehab and Return to Play

Rehabilitation

  • Begin with low to moderate intensity exercise[46]
  • Progress as tolerated
  • Closely monitored for pain, hematuria, or urinary symptoms during activity

Return to Play/ Work

  • Return to play criteria include[47]
    • Complete symptom resolution
    • No evidence of obstruction or infection
    • Stable renal function
    • Individualized risk assessment

Prognosis and Complications

Prognosis

  • Recurrence Rate
    • High, up to 50% of patients experience another episode within 5 years of the initial stone[48]
  • Surgical management
    • Many stones will require surgical intervention
  • Risk of kidney injury[49]
    • Absolute risk of progressing to ESRD or CKD is low
    • Relative risk is increased compared to the general population
    • Risk increases with recurrent stones, large stone burden, certain stone types (e.g., struvite, uric acid), or underlying comorbidities

Complications

  • Chronic Kidney Disease
    • Uncommon but possible
    • End stage renal disease (ESRD) even less common
  • Obstruction
  • Infection
  • Recurrence
  • Intractable pain or nausea and vomiting

See Also

References

  1. ↑ Scales Jr, Charles D., et al. "Prevalence of kidney stones in the United States." European urology 62.1 (2012): 160-165.
  2. ↑ Sakhaee, Khashayar, Naim M. Maalouf, and Bridget Sinnott. "Kidney stones 2012: pathogenesis, diagnosis, and management." The Journal of Clinical Endocrinology & Metabolism 97.6 (2012): 1847-1860.
  3. ↑ Sakhaee K. Nephrolithiasis as a systemic disorder. Curr Opin Nephrol Hypertens 2008;17:304–9.
  4. ↑ Eren, Elif, et al. "Mineralogy, geochemistry, and micromorphology of human kidney stones (urolithiasis) from Mersin, the southern Turkey." Environmental Geochemistry and Health 45.7 (2023): 4761-4777.
  5. ↑ Alelign, Tilahun, and Beyene Petros. "Kidney stone disease: an update on current concepts." Advances in urology 2018.1 (2018): 3068365.
  6. ↑ Kumar, Aashish, et al. "Insights from a brief study of renal calculi: recent diagnostic and treatment approaches." Journal of Bio-X Research 7 (2024): 0002.
  7. ↑ Ingimarsson JP, Krambeck AE, Pais Jr VM. Diagnosis and management of nephrolithiasis. Surg Clin N Am 2016;96:517–32.
  8. ↑ Smith LH. Renal stones. Solutions and solute. Endocrinol Metab Clin North Am 1990;19:767–72.
  9. ↑ Theisen, Katherine M., et al. "Defining 24-hour urine parameters and kidney stone risk of student athletes." Clinical Nephrology 97.2 (2022): 86.
  10. ↑ Wang, Yuanfu, et al. "Is vigorous physical activity effective for preventing kidney stones?." Frontiers in Public Health 13 (2025): 1612347.
  11. ↑ Jones, Patrick, et al. "Do lifestyle factors including smoking, alcohol, and exercise impact your risk of developing kidney stone disease? Outcomes of a systematic review." Journal of endourology 35.1 (2021): 1-7.
  12. ↑ Dobbins, John W., and Henry J. Binder. "Importance of the colon in enteric hyperoxaluria." New England Journal of Medicine 296.6 (1977): 298-301.
  13. ↑ Robert, Maxime, et al. "Evaluation of the risk of stone formation: study on crystalluria in patients with recurrent calcium oxalate urolithiasis." European urology 29.4 (1996): 456-461.
  14. ↑ Pfau, Anja, and Felix Knauf. "Update on nephrolithiasis: core curriculum 2016." American Journal of Kidney Diseases 68.6 (2016): 973-985.
  15. ↑ Robert, Maxime, et al. "Evaluation of the risk of stone formation: study on crystalluria in patients with recurrent calcium oxalate urolithiasis." European urology 29.4 (1996): 456-461.
  16. ↑ Shokeir, Ahmed A. "Renal colic: new concepts related to pathophysiology, diagnosis and treatment." Current opinion in urology 12.4 (2002): 263-269.
  17. ↑ Kobayashi, Takashi, et al. "Impact of date of onset on the absence of hematuria in patients with acute renal colic." The Journal of urology 170.4 Part 1 (2003): 1093-1096.
  18. ↑ Shafi, Salman Tahir, Roshina Anjum, and Tahir Shafi. "Clinical predictors of an abnormal ultrasound in patients presenting with suspected nephrolithiasis." Pakistan Journal of Medical Sciences 33.3 (2017): 545.
  19. ↑ Case courtesy of Harshavardhan Balaganesan, Radiopaedia.org, rID: 33976
  20. ↑ Image courtesy of renalfellow.org
  21. ↑ Bukhari, Sumera, et al. "Persistent hematuria caused by renal cell carcinoma after aortic valve replacement and warfarin therapy." Baylor University Medical Center Proceedings. Vol. 30. No. 3. Taylor & Francis, 2017.
  22. ↑ Dhar, Mrinal, and John D. Denstedt. "Imaging in diagnosis, treatment, and follow-up of stone patients." Advances in chronic kidney disease 16.1 (2009): 39-47.
  23. ↑ Levine, Jonathan A., et al. "Ureteral calculi in patients with flank pain: correlation of plain radiography with unenhanced helical CT." Radiology 204.1 (1997): 27-31.
  24. ↑ Heidenreich, Axel, F. Desgrandschamps, and F. Terrier. "Modern approach of diagnosis and management of acute flank pain: review of all imaging modalities." European urology 41.4 (2002): 351-362.
  25. ↑ Hamm, Michael, et al. "Low dose unenhanced helical computerized tomography for the evaluation of acute flank pain." The Journal of urology 167.4 (2002): 1687-1691.
  26. ↑ Dym, R. Joshua, et al. "Renal stones on portal venous phase contrast-enhanced CT: does intravenous contrast interfere with detection?." Abdominal imaging 39.3 (2014): 526-532.
  27. ↑ Corwin, Michael T., et al. "Detection of renal stones on portal venous phase CT: comparison of thin axial and coronal maximum-intensity-projection images." American Journal of Roentgenology 207.6 (2016): 1200-1204.
  28. ↑ Goertz, Jacob K., and Seth Lotterman. "Can the degree of hydronephrosis on ultrasound predict kidney stone size?." The American journal of emergency medicine 28.7 (2010): 813-816.
  29. ↑ Yan, Justin W., et al. "Normal renal sonogram identifies renal colic patients at low risk for urologic intervention: a prospective cohort study." Canadian Journal of Emergency Medicine 17.1 (2015): 38-45.
  30. ↑ Mitterberger M, Aigner F, Pallwein L, et al. Sonographic detection of renal and ureteral stones. Value of the twinkling sign. Int Braz J Urol 2009 Sep–Oct;35(5):532–9.
  31. ↑ Kanno, Toru, et al. "Determining the efficacy of ultrasonography for the detection of ureteral stone." Urology 84.3 (2014): 533-537.
  32. ↑ Abrahamian, Fredrick M., et al. "Association of pyuria and clinical characteristics with the presence of urinary tract infection among patients with acute nephrolithiasis." Annals of emergency medicine 62.5 (2013): 526-533.
  33. ↑ Eskelinen, Matti, Jorma Ikonen, and Pertti Lipponen. "Usefulness of history-taking, physical examination and diagnostic scoring in acute renal colic." European urology 34.6 (1998): 467-473.
  34. ↑ Bove, Peter, et al. "Reexamining the value of hematuria testing in patients with acute flank pain." The Journal of urology 162.3 (1999): 685-687.
  35. ↑ Worcester, Elaine M., et al. "Renal function in patients with nephrolithiasis." The Journal of urology 176.2 (2006): 600-603.
  36. ↑ Moore, Christopher L., et al. "Derivation and validation of a clinical prediction rule for uncomplicated ureteral stone—the STONE score: retrospective and prospective observational cohort studies." Bmj 348 (2014).
  37. ↑ Gottlieb, Michael, Brit Long, and Alex Koyfman. "The evaluation and management of urolithiasis in the ED: A review of the literature." The American journal of emergency medicine 36.4 (2018): 699-706.
  38. ↑ Zulkifli, M. Z., et al. "Ureteric stone in the presence of existing backache: lessons to learn." Clin Ter 163.1 (2012): 23-25.
  39. ↑ Campschroer T, Zhu Y, Duijvesz D, et al. Alpha-blockers as medical expulsive therapy for ureteral stones. Cochrane Database Syst Rev 2014 Apr 2(4):CD008509.
  40. ↑ Worster, Andrew S., and Wendy Bhanich Supapol. "Fluids and diuretics for acute ureteric colic." Cochrane Database of Systematic Reviews 2 (2012).
  41. ↑ Coll DM, Varanelli MJ, Smith RC. Relationship of spontaneous passage of ureteral calculi to stone size and location as revealed by unenhanced helical CT. AJR Am J Roentgenol 2002 Jan;178(1):101–3.
  42. ↑ Sun, Beth Yu-Chen, et al. "Recurrence rate and risk factors for urinary calculi after extracorporeal shock wave lithotripsy." The Journal of urology 156.3 (1996): 903-906.
  43. ↑ Bihl, Geoffrey, and Anthony Meyers. "Recurrent renal stone disease—advances in pathogenesis and clinical management." The Lancet 358.9282 (2001): 651-656.
  44. ↑ Qaseem, Amir, et al. "Dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults: a clinical practice guideline from the American College of Physicians." Annals of internal medicine 161.9 (2014): 659-667.
  45. ↑ Worcester, Elaine M., and Fredric L. Coe. "Calcium kidney stones." New England Journal of Medicine 363.10 (2010): 954-963.
  46. ↑ Fontenelle, Leonardo Ferreira, and Thiago Dias Sarti. "Kidney stones: treatment and prevention." American family physician 99.8 (2019): 490-496.
  47. ↑ Bargagli, Matteo, et al. "Kidney stone disease: risk factors, pathophysiology and management." Nature Reviews Nephrology (2025): 1-15.
  48. ↑ Khan, Saeed R., et al. "Kidney stones." Nature reviews Disease primers 2.1 (2016): 1-23.
  49. ↑ Alexander, R. Todd, et al. "Kidney stones and kidney function loss: a cohort study." Bmj 345 (2012).
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John Kiel on 13 November 2025 20:18:51
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