Kidney Stones

Kidney stones occur when the urine has a high level of minerals that form stones. Most kidney stones are made from calcium. Minerals such as uric acid and oxalate may also form stones. These stones can irritate kidney tissue and block urine flow.

Some stones can grow to be very large without causing symptoms. Severe flank pain is a common symptom of kidney stones. Flank pain occurs on one side of the back near the lower ribs.

If stones have passed into the ureter, the person may have groin pain. Pain may also radiate down the lower side of the abdomen. A kidney stone may also cause blood in the urine, nausea, and vomiting.

Kidney stones are caused by an accumulation of mineral salts, most commonly calcium. People with kidney stones may first have dysfunction or damage to some of the collecting tubes in the kidney.

Factors that increase the risk of stone formation include:

• abnormalities in metabolism of a mineral, such as uric acid
• diet high in a mineral, such as calcium
• hereditary factors
• inadequate fluid intake
• lack of kidney stone inhibitors, such as magnesium, in the urine
• living in a hot, dry climate

Maintaining a high fluid intake is the most important step an individual can take to avoid this problem. People with a history of kidney stones should drink enough fluid to produce at least 2 liters (about 2 quarts) of urine each day.

Diagnosis of kidney stones begins with a medical history and physical exam. The healthcare professional may order tests, including:

• an abdominal X-ray known as a KUB, which examines the kidneys, ureter, and bladder
• a complete blood count (CBC) to look for infection or chronic disease
• a CT scan to look for tumors or other anatomic abnormalities
• an intravenous pyelogram to detect stones in the urinary system
• kidney function tests, to look for signs of kidney disease
• an ultrasound of the urinary system
• a urinalysis to check for blood or signs of infection in the urine

Serious complications are unusual. Most urinary stones require treatment simply because of the intense pain that they cause. Some of the serious complications of kidney stones include:

• kidney damage due to blockage over a long period of time
• kidney infection
• systemic or whole body infection
• a urinary fistula, which is an abnormal connection between the urinary system and some other organ in the body

Kidney stones are not contagious and pose no risk to others.

There are medical and surgical components to the treatment of kidney stones. Medical care is first directed toward managing pain or infection. Afterward, treatment is directed at preventing more stones from forming. Mineral levels in the urine are sometimes measured by analysis of a 24-hour collection of urine. This information is used to determine the steps needed to prevent future stones. These may include dietary changes or medication.

Many stones will pass out of the body on their own during urination. People are often given pain medication and told to drink a lot of fluids. They are then observed for a day or two to see if the stone passes. If the stone is very large on X-ray or will not pass, further treatment is needed.

Some types of stones can be dissolved with oral medications. Stones containing calcium cannot be dissolved using medication. If this type of stone does not exit the body on its own, further steps are required. One type of treatment is lithotripsy, which uses shock waves aimed at the kidney stones from outside the body. The shock waves often break up the stones into small pieces. The small pieces can then be passed out of the body in the urine.

Surgery may be needed to remove the stone or stones. There are several surgery options. One method involves removing stones through a small, lighted tube called an endoscope. The endoscope can be passed through the urethra into the body. The urethra is the tube that carries urine out of the body. The endoscope can then be advanced into the bladder or ureters to see the stone. The stone can then be removed through the endoscope.

Another type of endoscope is larger. It is inserted directly into the kidney through the skin of the abdomen. Larger stones can be removed this way. The majority of stones can be treated with one of these methods. If not, traditional open surgery may be needed.

Pain medications may cause drowsiness, constipation, or allergic reactions. Surgery can be complicated by bleeding, infection, or reactions to anesthesia. Several of the medications used to prevent further stone formation may cause stomach or bowel upset.

If stones pass on their own or are removed, a person can usually return to normal activities. Prevention of future stones is stressed. The person will be advised to drink plenty of fluids every day. Medications are helpful in some cases to prevent further stones.

People may be checked periodically with regular or special X-ray tests to see if stones are forming again. If a surgical procedure was difficult or complicated, additional X-ray tests may be used to check for urinary tract blockage. Any new or worsening symptoms should be reported to the healthcare professional.