Medical Predisposition
We have already identified groups most predisposed to stone formation.
Predisposition can be biochemical or anatomical such as urinary tract structural abnormalities [3].
Biochemical predispostion to stone formation
These include:
- Hypercalciuria
- Hypericosuria
- Hyperoxaluria
- Hypocitraturia
- Cystinuria
- Urease producing organisms
- Urea splitting organisms (proteus, klebsiella, serratia and mycoplasma), which produce struvite stones
Anatomical predispostion to stone formation
These include:
- Pelvi-ureteric junction obstruction
- Hydronephrotic renal pelvis or calyces
- Calyceal diverticulum
- Horseshoe kidney
- Ureterocoele
- Vesicoureteric reflux
- Ureteral stricture
- Medullary sponge kidney
Other aetiologies
Other aetiologies may include:
- Insulin resistant states
- Hypertension
- Primary hyperparathyroidism
- Gout
- Metabolic acidosis
Specific features to look for in the history should include: use of diuretics, high protein diet, family history of renal stones and history of recurrent Urinary Tract Infections.