A cyst is a closed pocket or pouch of tissue that can form anywhere in the body. Cysts can be filled with air or fluid. Cysts that form on the kidneys usually contain fluid. One or more cysts may develop on small tubes in the kidneys. The simple kidney cyst is different from the cysts that develop when a person has polycystic kidney disease, which is a genetic disease. Although its cause is not fully understood, the simple cyst is not an inherited condition. Simple kidney cysts become more common as people age. Nearly 30 percent of people over the age of 70 have at least one simple kidney cyst.
Most often, simple cysts do not cause symptoms or harm the kidney. In some cases, however, pain can occur when cysts enlarge and press on other organs. Sometimes cysts become infected or suddenly start to bleed. Less often the cysts impair kidney function. People with simple cysts are often found to have high blood pressure, although the cause-and-effect relationship is not well understood.
Kidney cysts are found by taking pictures of the kidneys using computerized tomography (CT) scans and ultrasonography. When simple cysts are found but no complications are present, no treatment is needed.
If cysts cause symptoms, treatment may be needed. One procedure involves puncturing the cyst using a long needle inserted through the skin. The doctor uses ultrasonography to guide the needle to the cyst. The cyst is drained and then filled with a solution containing alcohol to make the tissue harder.
If the cyst is large, surgery may be needed. Most procedures can be performed using a laparoscope, which allows for a smaller incision and quicker recovery. The surgeon drains the cyst then removes or burns away its outer tissue. Most patients stay in the hospital 1 or 2 days.
National Kidney and Urologic Diseases Information Clearinghouse
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The National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health of the U.S. Department of Health and Human Services.
Established in 1987, the Clearinghouse provides information about diseases of the kidneys and urologic system to people with kidney and urologic disorders and to their families, health care professionals, and the public. The NKUDIC answers inquiries, develops and distributes publications, and works closely with professional and patient organizations and Government agencies to coordinate resources about kidney and urologic diseases.
Publications produced by the Clearinghouse are carefully reviewed by both NIDDK scientists and outside experts.
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NIH Publication No. 07–4618