Kidney Stone 2

What are symptoms of kidney stones?

While some kidney stones may not produce symptoms (known as "silent" stones), people who have kidney stones often report the sudden onset of excruciating, cramping pain in their low back and/or side, groin, or abdomen. Changes in body position do not relieve this pain. The pain typically waxes and wanes in severity, characteristic of colicky pain (the pain is sometimes referred to as renal colic). It may be so severe that it is often accompanied by nausea and vomiting. Kidney stones also characteristically cause blood in the urine. If infection is present in the urinary tract along with the stones, there may be fever and chills.

How are kidney stones diagnosed?

The diagnosis of kidney stones is suspected by the typical pattern of symptoms when other possible causes of the abdominal or flank pain are excluded. Imaging tests are usually done to confirm the diagnosis. A helical CT scan without contrast material is the most common test to detect stones or obstruction within the urinary tract. Formerly, an intravenous pyelogram (IVP; an x-ray of the abdomen along with the administration of contrast dye into the bloodstream) was the test most commonly used to detect urinary tract stones, but this test has a greater risk of complications, takes longer, and involves higher radiation exposure than the non-contrasted helical CT scan. Helical CT scans have been shown to be a significantly more effective diagnostic tool than the IVP in the diagnosis of kidney or urinary tract stones.

In pregnant women or those who should avoid radiation exposure, an ultrasound examination may be done to help establish the diagnosis.

What is the treatment for kidney stones?

Most kidney stones eventually pass through the urinary tract on their own within 48 hours, with ample fluid intake. Pain medications can be prescribed for symptom relief. There are several factors which influence the ability to pass a stone. These include the size of the person, prior stone passage, prostate enlargement, pregnancy, and the size of the stone. A 4 mm stone has an 80% chance of passage while a 5 mm stone has a 20% chance. Stones larger than 9-10 mm rarely pass on their own and usually require treatment.

Some medications have been used to increase the passage rates of kidney stones. These include calcium channel blockers such as nifedipine and alpha blockers such as tamsulosin. These drugs may be prescribed some people who have stones that do not rapidly pass through the urinary tract.

For kidney stones which do not pass on their own, a procedure called lithotripsy is often used. In this procedure, shock waves are used to break up a large stone into smaller pieces that can then pass through the urinary system.

Surgical techniques have also been developed to remove kidney stones. This may be done through a small incision in the skin (percutaneous nephrolithotomy) or through an instrument known as an ureteroscope passed through the urethra and bladder up into the ureter.

How can kidney stones be prevented?

Rather than having to undergo treatment, it is best to avoid kidney stones in the first place. It can be especially helpful to drink more water. (The National Institutes of Health recommend drinking up to 12 full glasses of water a day, if you've already had a kidney stone.) Water helps to flush away the substances that form stones in the kidneys.

Depending on the cause of the kidney stones and an individual's medical history, dietary changes or medications are sometimes recommended to decrease the likelihood of developing further kidney stones. It is particularly helpful, if one has passed a stone, to have it analyzed in a laboratory to determine the precise type of stone so specific prevention measures can be considered.