A kidney stone is a mineral deposit that forms in the urinary tract. They develop when crystals in the urine begin to grow and gradually increase in size to form a rock-like mass. In the U.S. about one in ten will develop a kidney stone in his lifetime. In 2010, kidney stones were responsible for more than 600,000 emergency
Stones form from substances that are normally present in the urine. They include calcium, oxalate, phosphate, uric acid, and other chemicals. When there is an excess of any of these substances, crystallization and stone formation will occur. Dehydration is the number one cause of stones followed by diet, family history, work
environment and climate. There are substances in the urine called inhibitors which can prevent the crystal from forming. When the concentration or amount of these inhibitors are low, then crystals can form.
The number one symptom of kidney stones is pain in the back, abdomen, pelvis. The pain is intense and usually worsens as the stone moves. Most patients will experience nausea, vomiting, blood in the urine and difficulty urinating.
The best way of detecting a kidney or ureteral stone is a CT scan called a CT urogram which does not require an injection of dye and takes only a few minutes. Most patients are diagnosed in the emergency room and then referred to a urologist after the x-ray is performed and pain is managed.
Treatment of the stone depends on two factors. One is the location and the other is the size. Most stones are small and are anywhere from 1-3mm. These are the ones which will usually pass after hydration, pain management but are also the most painful. Pain results when the stones move out of the kidney and lodge into the ureter and cause
blockage of the urinary tract.
Surgery consists of shock wave lithotripsy (SWL) which is an outpatient procedure. Patients are placed on a table which delivers shock waves that are focused on the stone. Live images of the stone are used during the procedure to gauge the location and degree of stone fragmentation.
When stones are too large, too hard or too difficult to manage with SWL, then ureteroscopic stone extraction is then performed. This is a special instrument which is a fiberoptic tube that can be inserted into the ureter and also the kidney. Once the stone is visualized, it can then be fragmented with a laser, trapped with a basket and removed.
Most stones contain calcium and calcium oxalate is the most common stone. Stones can also recur and prevention is critical in this disease. Blood and urine tests are performed to identify risk factors for stone formation. All patients need to increase their fluid intake to make the urine more dilute. Coffee, tea should be limited as well
as carbonated beverages.
Avoid high-dose vitamin C supplements (500mg is the high end). Lemonade is an excellent source of citrate and has been shown to reduce kidney stones. Other substances shown to be helpful in reducing stones are Vitamin B6, magnesium, and potassium. The most common supplement is potassium citrate.
Dietary modification especially lowering consumption of animal protein (meats, eggs, cheese) is critical.
Reduction of sodium (salt) will decrease calcium in the urine. Most believe that sodium should be limited to 2,000 mg per day.
Taking high doses of certain calcium supplements can increase stone formation. Calcium citrate is the ideal supplement to take.
Monitor intake of oxalate (chocolate, cocoa, spinach, dark leafy greens, strawberries, peanuts, peanuts)