Kidney Stones | A Simple Patient Guide

What is a kidney stone?

The kidneys filter the blood and form urine. Kidney stones are deposits that form from mineral and acid salts in the kidney. They vary in size from the size of a grain of sand to large stones that can block drainage from the kidneys. Kidney stones form when there is an excess of a crystal–forming substance such as calcium or uric acid in the blood. A common cause is dehydration, sometimes as a result of failing to drink enough water and sometimes as a result of fluid loss in very hot weather among people who work out of doors. In conditions of excess crystal-forming substances, your kidneys cannot adequately dilute the urine, and stones will precipitate. If you have a kidney stone, you will be diagnosed with nephrolithiasis.

Symptoms of kidney stones

Kidney stones travel throughout the urinary tract, from the kidneys through the ureters to the bladder. The primary symptom is sudden severe pain, frequently in the back and radiating to the groin. The pain occurs when the kidney stone moves through the urinary system, so you may develop kidney stones that are painless until they leave the kidney. Other symptoms are blood in the urine, nausea, and vomiting. If you have a kidney stone, you should contact a physician or visit the emergency department as soon as possible.

Diagnosis of a kidney stone

When you visit the doctor with a possible kidney stone, your doctor will determine if your history and physical examination suggests that is the diagnosis. A urinalysis will usually be obtained to look for blood that may not be visible to the naked eye. The diagnosis of a kidney stone is often made by CT scan, ultrasound, or by injecting dye into your vein and taking x-rays that show the dye as it filters through the urinary system This test is known as an intravenous pyelogram, or IVP. Your doctor may ask you to collect or to strain your urine in order to determine the cause of the kidney stone. Blood tests can also be helpful.

Treatment of kidney stones

In most cases, the treatment for kidney stones is hydration and pain medication. You may receive some intravenous (IV) fluid, if you visit the emergency department. You will have to drink an adequate amount of water to allow the stone to pass. If the stone does not pass with conservative treatment, then you may need a treatment of extracorporeal shockwave lithotripsy, which uses shock waves to break the kidney stone into small pieces that are easy to pass in the urine. Sometimes, a urologist may need to retrieve the stone using special instruments that can retrieve a stone from the urinary tract. Some patients will require a stent to keep the ureter open so stones can pass easily.