Kidney nontumor / medical renal



Urolithiasis (stones)

Last author update: 3 December 2012
Last staff update: 20 September 2023

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PubMed Search: Urolithiasis stones human

Nikhil Sangle, M.D.
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Cite this page: Sangle N. Urolithiasis (stones). website. Accessed September 30th, 2023.
Definition / general
  • Stones within collecting system of kidney are present in 5 - 10% of Americans; most commonly in men ages 20 - 49
  • Due to supersaturation of stone constituents, decreased urine volume or deficiency of crystal inhibitors in urine
Clinical features
  • 80% unilateral, usually in calyces, pelvis or bladder
  • Usually only 2 - 3 mm, but with severe, abrupt flank pain and hematuria
  • All stones contain an organic matrix of mucoprotein
Types of stones
  • Calcium oxalate / phosphate (75%): due to hypercalciuria (idiopathic, 50%), hypercalcemia (infants may have high Vitamin D levels, Iran J Kidney Dis 2012;6:186), hyperoxaluria (in vegetarians with oxalate rich diet), hyperuricosuria (hyperparathyroidism, bone disease, sarcoidosis) and rarely primary hyperoxaluria (Arch Pathol Lab Med 2002;126:1250); oxalate crystals are highlighted by polarized light; are accompanied by foreign body giant cells and macrophages
  • Struvite (triple stones, magnesium ammonium phosphate, 15%): due to urea splitting bacteria (Proteus, Staphylococcus); produce staghorn calculi
  • Uric acid (6%): due to hyperuricemia, chemotherapy for leukemia, uricosuric drugs or excess dietary proteins; 50% lack elevated uric acid in blood / urine; may be due to acidic pH; radiolucent; may become staghorn calculi if in renal pelvis; elongated and rectangular crystals in collecting tubules or doubly refractile crystals in interstitium with giant cell reaction
  • Cysteine (1%): due to genetic defects in cystine transport (Orphanet J Rare Dis 2012;7:19); autosomal recessive, affects 1 per 20,000; yellow-brown and radioopaque stones form at low urinary pH; crystals are flat hexagons in urine
  • Ammonium acid urate: rare, but more common in Asia (Kaohsiung J Med Sci 2012;28:259)
  • Stone granuloma: complication of ureteral stone fragmentation and instrumentation
  • Xanthinuria (rare): autosomal recessive, due to deficient xanthine oxidase, causing excessive xanthine levels and stones in 1/3 with this disorder
Diagrams / tables

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Passage of a calculus (stone)

Case reports
  • 48 year old man with nephrectomy for renal mass due to urolithiasis caused by 2,8-dihydroxyadenine crystals (Hum Pathol 1992;23:1081)
Gross images

Contributed by Jian-Hua Qiao, M.D.
Multiple kidney stones

Multiple kidney stones

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