Snapshot A 30-year-old man presents to the emergency department with severe, colicky left flank pain of acute onset that radiates to the left groin. He also reports urinary frequency and urgency. Physical examination is significant for left-sided costovertebral angle tenderness. Urine dipstick is heme positive. Urinalysis also shows envelope-shaped crystals. A non-contrast abdominal CT is shown. Introduction Clinical definition login to view 1 more bullet Nephrolithiasis StonesStone TypeEtiologyImaging Finding(s)Stone ShapeTreatmentCalciumHypercalciuriae.g.,idiopathic hypercalcemiaHypocitraturiaprecipitates calcium oxalate stonesEthylene glycol (antifreeze)Vitamin C abuseCrohn diseaseUrine alkalinizationprecipitates calcium phosphate stonesRadiographyradiopaqueComputerized tomographyradiopaqueEnvelope or dumbbell shapecalcium oxalateWedge-shaped prismcalcium phosphateHydrochlorothiazideCitrateLow-sodium dietCystineImpaired cystine reabsorption in the proximal convoluted tubulethis results in cystinuriaPrecipitates in acidic urineDiagnosiscyanide-nitroprusside testRadiographyradiopaqueComputerized tomographyvisible at timesHexagonalDietary modificationlow sodiumUrine alkalinizationChelating agentsin refractory casesStruvite (magnesium ammonium phosphate)Urease-positive organisms such asProteus mirabilisStaphylococcus saphrophryticusKlebsiellaUrease-positive organisms subesequently alkalinize the urinethis causes struvite stones due to precipitationRadiographyradiopaqueComputerized tomographyradiopaqueCan result in a staghorn calculiCoffin lidRemoval of underlying infectionSurgical removal of the stoneUric acidHyperuricemiae.g., states of increased cell turnover and goutPrecipitates in acidic urineRadiographyradiolucentComputerized tomographyminimally visibleRhomboid/rosetteUrine alkalinizationAllopurinolAdequate hydration prior to chemotherapy treatment Epidemiology Prevalence login to view 1 more bullet Risk factors login to view 17 more bullets Etiology Pathogenesis login to view 2 more bullets Presentation Symptoms login to view 4 more bullets Physical exam login to view 2 more bullets Imaging Renal ultrasound login to view 4 more bullets Non-contrast computerized tomography (CT) login to view 4 more bullets Studies Labs login to view 9 more bullets Diagnostic criteria login to view 1 more bullet Differential Urinary tract infections Acute pyelonephritis Groin hernia Treatment Medical login to view 7 more bullets Operative login to view 8 more bullets Complications Ureteral obstruction Ureteral stricture Urinary tract infection Renal deterioration Prognosis Small stones are more likely to spontaneously pass