Preventing Kidney Stones After Kidney Stone Surgery

It is a well-documented fact that even after surgical removal of kidney stones, up to 50% of patients may have recurrence within 5 years. Therefore, some preventive measures must be taken in order to avoid kidney stones in the future.

In the longer term, a daily urine output of at least 2 liters is advised in all patients with stone disease. Fluid intake should be before be about 3 liters per day — more if the climate or the patient's occupation causes much sweating. Suitable measures should be fitted to correct any known cause of stone formation. Preparations containing vitamin D must be avoided, even milk intake has to be reduced.

Idiopathic hypercalciuria can be helped by reduction of sodium intake (low salt intake) and by the use of a thiazide diuretic. Reduction of calcium intake is not recommended unless it is very high, as it may lead to a negative overall calcium balance and reduction of bone mass which extremely makes bones weaker, also reduction of calcium intake increases increased oxalate absorption and excretion.

Citrate excretion can be increased by daily administration of potassium nitrate or potassium bicarbonate. Alternately, lemon juice may be a very good dietary source. Hypokalaemia should be preceded as it leads to a reduction in citrate excretion.

In patients with recurrent oxalate stones, foods and some liquids rich in this salt, such as rhubarb, spinach, tomatoes, strawberries, chocolate and tea, should be avoided. Persons who have passed several uric acid or urate stones benefit from allopurinol, 100-300 mg daily, depending on renal function. Allopurinol also has a place in treating calcium oxalate stone disease, since urates may contribute by acting as a nidus (nest) for stone formation.

Phosphate-containing calculi are formed only in alkaline urine; hence acidifying the urine by giving ammonium chloride may be effective. In contrast, cystine and urate stones may be prevented or sometimes dissolved, by giving sufficient sodium bicarbonate to make the urine persistently alkaline, and ensuring a high urine output of 2-4 liters / day. When these measures fail or are unacceptable to the patient, treatment with D-penicillamine, a chelating agent, in a dose of 1-1.5 gram daily may be tried, although it is frequently associated with significant side effects.

In case of struvite stones, which are actually magnesium-ammonium-phosphate stones and quite common in women with recurrent urinary tract infections, protease inhibitors are advised. Frequently, struvite stones are large staghorn calculi, and urine pH is high. These stones are formed due to infection with urease producing organisms such as Proteus mirabilis, Pseudomonas, Klebsiella, Staphylococcus and Mycoplasma but not E.coli. Therefore, struvite stones are also called as Infection stones.