Kidney stones

	aka Nephrolithiasis
Etiology	Site: Pelvi-ureteric junction/proximal ureter, intramural ureter/VUJ, where ureter crosses iliac vessels. - 80% Ca oxalate (or phosphate); - struvite (1-5%) frequently associated with Proteus, Pseudomonas or Klebsiella = urease-producing organism - rarely uric acid (10%) or cystine (1% - IEM).
Epidemiology	iatrogenic, age, M>F, BMI ↑, dehydration. Incidence: 1-2/1000
Clinical presentation	renal colic = flank pain referred to genitals, N+V. Chronic: little pain, ↓ renal function
Pathogenesis	↑ intraluminal pressure = pain
Diagnostic investigations	CT KUB = gold standard ➥ Bloods: serum Ca, phosphate, uric acid ➥ urine dip/MSU ➥ IV urogram → indicates function
Management	Acutely: ➥ analgesia (diclofenac PR; IV paracetamol if NSAIDs contraindicated) ➥ stent or percutaneous nephrostomy if obstructed Stable patient/as outpatient: ➥ shockwave lithotripsy ➥ J-J stent ➥ endoscopy ureteroscopy ➥ percutaneous nephrolithotomy ➥ prevention: ↓ Na diet, fluids, fibre, optimise protein intake ➥ Staghorn calculi → ↑ risk Proteus UTI

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