Alternative Names nephrolithiasis, urolithiasis, urinary calculi
Definition The deposit of mineral salts in the kidneys, called calculi, can form kidney "stones." Most of the time, these are made out of calcium. These stones can pass into the tube that connects the kidneys to the bladder, which is called the ureter.
What is going on in the body? Kidney stones are a common condition. Stones develop when there is an excess of stone-forming minerals in the urine. They can cause a great deal of pain.
What are the signs and symptoms of the condition? Pain on one side of the back near the lower ribs, or flank, is a common symptom of stones in the kidneys. Stones that have passed into the ureter also cause flank pain, and can cause pain in other parts of the body, as well. These areas include the groin and the scrotum in men or the labia, which are the skin folds around the vagina, in women. Pain can also radiate down the lower side of the abdomen.
Another symptom is blood in the urine. Some stones can grow to be very large without causing symptoms. When symptoms finally occur, they can include large amounts of blood in the urine or infection.
What are the causes and risks of the condition? The following factors can cause urinary stones:
elevated urinary levels of certain minerals, such as calcium, oxalate, and uric acid. This may occur because of a person's diet. Abnormalities in metabolism also play a role.
lack of kidney stone inhibitors in the urine. Citrate and magnesium, which naturally occur in urine, provide this function. A decreased level of one of these substances leads to stone formation.
inadequate fluid intake. This results in concentrated urine. This is a major factor in stone formation.
What can be done to prevent the condition? Maintaining a high fluid intake is the most important step an individual can take to avoid this problem. People with urinary stone disease should drink enough fluid to produce at least 2 litres of urine each day.
How is the condition diagnosed? The history and physical examination usually make a doctor suspect kidney stones. Analysis of the urine in affected people usually reveals the presence of blood. Blood tests may show evidence of an infection or problems with kidney function in some cases.
Most of the time, kidney stones show up on abdominal x-rays. Other special x-ray tests are also frequently used to diagnose kidney stones.
What are the long-term effects of the condition? Serious complications of kidney stone disease include:
kidney infection
systemic or whole body infection
formation of a urinary fistula, which is an abnormal connection between the kidney, bladder, or ureter and some other organ in the body
kidney damage due to blockage over a long period of time
Serious complications are unusual. Most urinary stones require treatment simply because of the intense pain that the stones cause.
What are the risks to others? This condition is not contagious and poses no risk to others.
What are the treatments for the condition? There are medical and surgical components to the treatment of urinary stones. Medical care is first directed toward managing any pain or infection if present. 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 on their own. People are often given pain medication, told to drink a lot of fluids, and observed for a day or two to see if the stone passes. If the stone is very large on x-ray or doesn't pass, further treatment is needed.
Some types of stones can be dissolved with oral medications. Stones containing calcium, which is the most common type of stone, cannot be dissolved using medication. If this type of stone does not exit the body on its own, some other treatment is 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 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 or open surgery may be needed, which is rare.
What are the side effects of the treatments? Tubes and catheters are usually placed temporarily following many of the surgical treatments. These may cause discomfort, frequent urination, or a urine infection. There are very few complications associated with shock waves. Using an endoscope is also fairly safe. However, bleeding, infection, or damage to the urine system may occur with any type of surgery or use of an endoscope.
Several of the medications used to prevent further stone formation may cause stomach or bowel upset.
What happens after treatment for the condition? If stones pass on their own or are removed, a person is "cured," and can usually return to normal activities. Prevention of future stones is stressed. This is primarily done by drinking large amounts of fluids to avoid dehydration. Medications are helpful in some cases to prevent further stones.
How is the condition monitored? After stones have been removed, the individual is sometimes given a course of medications to prevent stones from returning. 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.
Author: Stuart Wolf, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
