Kidney stones are small, hard mineral deposits that form in the kidney. They may stay in the kidney or travel down the urinary tract.
The medical term for kidney stones is nephrolithiasis. The medical term for stones occurring in the urinary tract is urolithiasis.
Each year, more than 500,000 people visit emergency rooms for kidney stone problems. Kidney stone disease is one of the oldest and most common problems of the urinary system.
There are four main types of kidney stones:
Calcium-oxalate stones (the most common type) can be caused by foods with salt or oxalates, some medicines, genetics and other kidney problems
Struvite stones affect women more than men and can grow very large
Uric acid stones may be caused by eating too much animal protein or by genetics
Cystine stones are very rare, caused by a genetic kidney disease called cystinuria
Stones in the kidney often do not cause any symptoms and can go undiagnosed. When a stone leaves the kidney, it travels to the bladder through the ureter. Sometimes, the stone can become lodged in the ureter.
When the stone blocks the flow of urine out of the kidney, it can cause the kidney to swell, often causing a lot of pain. Kidney stones come in virtually any color; but most are yellow or brown.
If you've had a kidney stone and want to avoid another one:
Drink water throughout the day. Remember to drink more to replace fluids you've lost when you sweat from exercise or are in hot weather
Avoid foods high in oxalates, such as blackberries, concord grapes, eggplant, nuts and soy cheese
Reduce the amount of animal protein (red meat, pork, etc.) in your diet
Kidney stones vary in size. They can be as small as a grain of sand or as large as a pearl. Some stones are even the size of a golf ball!