Kidney stones (nephrolithiasis) (mechanism of disease)

This flowchart on kidney stones covers the etiology, pathophysiology, manifestations, and pharmacology.

ERRATUM: staghorn calculi are most commonly associated with struvite stones

ADDITIONAL TAGS:
Hydronephrosis
UTI with urease- producing bacteria: urea → ammonia
Blockage of flow
Signs / symptoms
Tests / imaging / labs
Risk factors / SDOH
Inflammation / damage
Crystallization
Nephrolithiasis (kidney stones)
Medicine / toxins
Infectious / microbial
Biochem / molecular bio
Diet / nutrition
Genetics / hereditary
Neoplasm / cancer
Pathophysiology
+ Pharmacology
Etiology
Manifestations
Urine becomes supersaturated, where solvent contains more solute than can be held in solution → formation of:
Calcium oxalate stones (∼75%): Micro: biconcave dumbbells or bipyramidal envelopes ; Radiopaque
Uric acid stones (∼10%): Micro: rounded rhomboids, rosettes, or needle-shaped ; Radiolucent
Struvite stones (5-10%): Micro: rectangular prisms (coffin lid-appearance) ; Weakly radiopaque
Calcium phosphate stones (5%): Wedge-shaped prisms ; Radiopaque
Cystine stones (5%):
Micro: hexagon-shaped ; Weakly radiopaque
Xanthine stones (5%):
Micro: amorphous ; Radiolucent
Hypercalciuria
Hyperoxaluria
Hypocitraturia
Excess vitamin C
Ethylene glycol (antifreeze)
IBD → fat malabsorption → fat binds Ca, leaves oxalate to be absorbed
♂ ♀
Age 45-70
Family history
Loop diuretics
Low fluid intake, dehydration
Gout
Hyperuricemia
Hyperuricosuria
Leukemia
Chemotherapy
High cell turnover
Proteus mirabilis
S. saprophyticus
Klebsiella
Hyperparathyroidism
Type 1 renal tubular acidosis
Autosomal recessive defect in cystine- reabsorbing PCT transporter → cystinuria
Hereditary def of xanthine oxidase → failure to convert xanthine to uric acid → xanthinuria
Indwelling cath
Nuts, beets, beans, rhubarb spinach, energy drinks
Fill the entire renal pelvis and calyces (staghorn calculi)
Asymptomatic if small
Severe unilateral colickly flank pain, radiates to lower abd or groin
+/- CVA tenderness
Distention of the renal capsule and/or ureter
Dysuria, frequency, urgency
Gravel or stone in urine
Bacterial infxn
Recurrent UTIs
Pyelonephritis
Urosepsis
Perinephric abscess
Kidney inflammation
Urinary obstruction
Permanent glomerular damage
Crystalluria
↑ WBC
AKI: ↑ BUN, ↑ Cr
Hematuria (gross or micro)
1st: NSAIDs, e.g., ketorolac 2nd: opioids, e.g., morphine
Tamsulosin (α-blocker)
Thiazide
Allopurinol
Antibiotics
Tiopronin