Then the patient suffers terrible pain until the stone finally passes, or until a physician uses a device to break up the stone or surgically removes it. Stones formed in the bladder tend to be larger than kidney stones and usually are symptoms of such underlying disorders as an enlarged prostate or urinary tract infection. Cause Stones usually begin forming in the kidney when the urine has become too concentrated. Various substances in the urine, such as calcium salts or uric acid, then begin crystallizing into small bits of hard material in the kidney. Over time the crystals grow in size.
New research suggests that most stones start with tiny bacteria that live in urine.
The tendency to form kidney stones has been shown to run in families. A tumor on the parathyroid gland also causes stones to form, but this is a fairly rare circumstance. Incidence Kidney stones are relatively common and affect anywhere from 240,000 to 720,000 people in the United States each year. The pain usually begins in the area near the kidney and gradually moves downward toward the groin. The pain comes in waves and can be very intense.