| Type | Prevalence | Composition | |
| Calcium oxalate | 75% | Spiky / mulberry shaped Caused by hypercalciuria (moans, stones, psychic groans) Rare enzyme deficiency Increased oxalate absorption: coeliac, diverticulae of bowel, chronic pancreatitis | |
| Ammonium phosphate | 15% | Associated with proteus infection "Staghorn calculi" (from urease) | |
| Urate | 5% | Primary gout: HGPRT deficiency (Leesh-Nyhan) Secondary gout: increased purine breakdown - tumours, RT, chemo, psoriasis... | |
| Cysteine | 3% | Results from primary cysteinuria, inborn error of metabolism | |
Management
- History: precipitants, family history, personal history
- Examination
- Investigations
- Urine dipstick - blood, nitrates (UTI cause)
- U/Es, serum electrolytes, WCC, CRP
- KUB - 90% renal tract stones are radio-opaque (calcium, ammonium , cysteine) - urate/xanthine stones radiolucent
- IVU: determines degree / level of obstruction (hydronephrosis) - sites for blockage: (1) renal pelvis (2) pelvic brim (3) insertion into bladder - contrast contraindicated in pregnancy, allergy, anaphylaxis, raised serum creatinine
- USS: - no contrast, detects stones >5mm, determines hydronephrosis and obstruction
- CT Abdo: identifies radio-opaque and lucent stones, secondary signs of obstruction
- Analgesia - morphine, pethidine, NSAIDs
- Hydration
Definitive treatment
| <4mm | 4-6mm | >5mm |
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