Dear Dr. B: I have a granddaughter, 20 years old, who had kidney stones at age17and is still periodically in discomfort because of them. It would be helpful to know foods to avoid for possible prevention, writes Mrs. M.
Dear Mrs. M: Pain due to kidney stone is a very unpleasant experience. I have seen patients roll in pain on the floor of emergency department. The pain may last minutes or hours. After a pain killer or sometimes spontaneously the pain goes away and everything is back to normal. As if nothing had ever gone wrong!
One out of ten Canadians will have a kidney stone at some point in their life. It is more common in men than in women. It is not that common in teenagers. Usually it affects people in middle age.
The urinary system is made up of the kidneys, the ureters, the bladder, and urethra. The systems main function is to eliminate waste products in the form of urine. The urine contains many chemicals. When the chemicals form crystals, they tend to stick together. These crystals can grow into a stone ranging in size from a grain to a golf ball. The stones cause pain when they get stuck or pass through the urinary system.
Most stones contain calcium oxalate crystals. Some are uric acid stones or cystine stones. Some people seem to be more prone to kidney stones than others. This is due to several reasons: recurrent urinary tract infections, drinking too little fluid, blockage of the urinary tract, confinement to chair or bed for prolonged periods, consuming diet rich in calcium oxalate or uric acid, too much of vitamin C or D, certain medications and metabolic illnesses.
The stone, when passed or removed, should be sent for chemical analyses. This will help in planning diet and preventive measures. About 20 percent of patients have no definite cause for stones and the best treatment for them appears to be high fluid intake. The majority of patients with kidney stones have treatable metabolic disorder that can be detected by blood and urine tests.
Certain medications can help dissolve kidney stones except the ones with calcium. Unfortunately these are the commonest type. Small ones pass spontaneously. The ones that do not pass are blasted by high energy shock waves (Lithotripsy). Stones larger than 2 cm require surgery.
How can we prevent kidney stones?
Kidney stones recur in about 50 percent of cases. Therefore it is important to take preventive measures to avoid some very painful moments and prevent permanent damage to the kidneys.
Drink plenty of water during the day and at night. Drink plenty after meals and exercise. Patients with calcium oxalate stones should avoid large amount of dairy products and foods high in oxalate content (tea or chocolate). Avoid large doses of vitamin C (4 grams or more daily) and avoid heavy use of antacids.
If you have uric acid stones then cut down on the amount of red meat you eat.
This is just an over view of preventive measures. You should see a urologist for definitive answers to a specific problem.
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