Urolithiasis/Nephrolithiasis

The best test for renal stones is Spiral CT scan

Commonest types of kidney stones are calcium oxalate stones.

These are radio-dense (ie can be seen on a KUB film)

Radio-lucent stones are made up of Uric acid or matrix (protein alone) or xanthine.

Cystine stones are faintly radio-dense due to their sulfur content (this fact is frequently tested on). Cystine stones are very soft thus shock wave treatment/lithotripsy  (ESWL) does not work on them as the stones do not shatter.

Stone forming patients have a 50 % chance of recurrence over a 10 year period.

Interventions are needed in those patients who either have symptoms (pain/hematuria) or obstruction and should be seen by a urologist.

The following 3 interventions aid in preventing recurrence.

1. Increased fluid intake (>2 Liters/day)

2. Decrease protein intake (animal protein)

3. Decrease salt intake (Na increases calciuria).

Those with a second episode of stones or those who actively pass gravel/stones should get a full metabolic evaluation including 24 hour urine collections.

2 Pharmacologic interventions that have been shown to be of definite benefit in calcium oxalate stone formers are 

1. Administer Pottassium Citrate (increases urinary citrate - which in turn inhibits calcium oxalate crystallization)

2. Administer Hydrochlorothiazide (decreases calciuria)

Uric acid management is done like gout.