How Do You Diagnose a Stone?
Initially, an accurate patient history is important, including the previous history of kidney stones, a history of urinary tract infections, the amount of fluid intake the individual has had, previous surgeries and the use of certain medicines. Patients who come to the emergency room with a possible stone attack need to have their urine examined carefully. More than 80 percent of the time, when a kidney stone is present, there is evidence of blood in the urine. However, the blood is not always visible and needs to be found with a microscope. Careful analysis of the urine can also reveal evidence of small crystals or an associated urinary tract infection.
During this evaluation, radiological tools may be necessary. One type of radiological examination is a KUB, which is an x-ray of the kidney, ureter and bladder. Calcium stones are easily spotted on a simple x-ray. KUB, however, is not effective for spotting non-calcium stones. In order to spot other types of stones on an x-ray, a patient will be injected with an IVP or intravenous pyelogram. This compound is absorbed by the kidney and seen on an x-ray. The x-ray then shows shows an outline of the kidney and its drainage into the bladder, so any region of blockage appears.
An ultrasound may be performed instead of an x-ray, which can quickly find determine an obstruction but cannot differentiate between the various types of stones. In difficult cases, a CAT scan is performed, which can show evidence of a stone in the kidney or in the tube from the kidney to the bladder.
