Treatment by Kidney Stone Type
Thiazides, water pills (diuretics), are sometimes prescribed to reduce high levels of urinary calcium (hypercalciuria) and to increase urinary volume. Salt (sodium) intake needs to be reduced for thiazides to be effective. Patients with hypercalciuria who do not respond to thiazide therapy may be prescribed orthophosphates to reduce calcium absorption and may be given moderate dietary calcium restrictions.
Patients should not reduce their calcium intake unless their physicians advise them to do so. Overly aggressive oral calcium restrictions have been shown to actually increase calcium stone disease. The reason for this is that calcium binds other minerals and chemicals like oxalate in the digestive tract. If the oral calcium intake is too low, then there is no intestinal oxalate binding and the oxalate absorption and urinary excretion increases dramatically. This results in a net increase in kidney stone production.
Patients with elevated uric acid levels (hyperuricosuria) are advised to reduce excessive dietary meat protein. Potassium citrate (medication that maintains the antacid level in urine) and/or allopurinol (medication that stops the production of uric acid) may also be prescribed. If the blood level of uric acid is high, then allopurinol is usually used. If the stones are pure uric acid stones, then potassium citrate supplementation is generally recommended.
Hyperoxaluria (high levels of urinary oxalate) may be mild, enteric, or primary. Mild hyperoxaluria is usually caused by an excess of dietary oxalate (found in tea, chocolate, cola, nuts, and green leafy vegetables). Prevention consists of daily doses of pyridoxine (vitamin B-6), which reduces oxalate excretion, increased fluids, phosphate therapy, and sometimes calcium citrate supplementation.
A low-oxalate, low-fat diet, increased fluid intake, and calcium supplementation is prescribed for enteric hyperoxaluria. This rare condition is often severe and is usually caused by an intestinal disorder (e.g., Crohn's disease, colitis). Calcium citrate, magnesium, iron, and cholestyramine may be given to reduce oxalate levels.
Primary hyperoxaluria is rare, severe, and caused by an inherited liver disorder. Primary hyperoxaluria requires aggressive treatment to prevent severe renal stone disease and kidney failure. High doses of vitamin B-6, orthophosphates, magnesium supplements, and increased fluid intake (to produce 2 liters of urine/day) are prescribed. Rarely, kidney and liver transplants are necessary.
Hypocitraturia (low levels of urinary citrate) usually requires a prescribed supplement, such as potassium citrate. The dosage depends on the level of urinary citrate, which is determined initially by the 24-hour urine test but can also be monitored by measuring the urinary antacid level (ph) with special dipsticks. Patients with renal tubular acidosis usually respond particularly well to treatment with prescription potassium citrate supplements. Citrus fruits and lemon juice can also be used as additional sources of natural potassium citrate.
Low Urine Volume
Low urinary volume is both the easiest and the hardest problem to solve. It can be very difficult for many stone patients to significantly increase their fluid level on a daily basis for long periods of time. Increasing fluid intake is the only known remedy that helps all types of stones, regardless of the chemical makeup of the stones.
While increasing fluid intake often is difficult at first, there are some helpful techniques to make the transition easier. First, try drinking a small glass of water, roughly 4 ounces, with each meal. Then, slowly increase the frequency of that extra small glass from mealtimes to in-between and other convenient times.
Follow the 24-hour urine volume—if the volume is close to 2000 cc (roughly ½ gallon), then you are probably doing fine. Once the urinary volume up to where it should be, your system will adjust and you will become used to this increased fluid. At that point, you will become thirsty if you skip some your usual water intake.
Measuring 24-hour urine volume is a far better way to manage fluid intake than an arbitrary number of glasses of water to drink. If you just can't stand any more water, try lemonade made with real lemon juice to break up the monotony. Real lemon juice also is rich in natural citrates.
Treatment for high cystine levels in the urine (cystinura) includes substantially increasing fluid intake and raising the pH of the urine (usually with sodium bicarbonate or potassium citrate). Penicillamine (Cuprimine) and tiopronine (Thiola) may also be prescribed.