Cysts (spherical, thin-walled fluid-filled sacs) may develop within the tissues of the kidneys singly or in groups. Single kidney cysts are not a health risk and are common after age 50. While cancer or infection may develop within one cyst, such complications are very rare. However, polycystic kidney disease, a common inherited disorder, may lead to the formation of hundreds of cysts, abnormally enlarged kidneys, and eventual kidney failure. (The disease may also cause cysts to develop in other organs, especially the liver.) Some children are born with the full-fledged disorder and others develop it early in life. More often, however, symptoms of polycystic kidney disease begin by ages 30 to 40. Major complications include kidney failure, high blood pressure, and bleeding around the brain from a ruptured aneurysm. There is yet no cure; goals of treatment are to preserve kidney function as long as possible, to prevent or treat complications, and to alleviate symptoms. Renal failure rarely occurs before age 40, and normal kidney function is maintained in about half of patients who reach age 70.
WHAT CAUSES KIDNEY CYSTS?
- The cause of single kidney cysts is unknown.
- In most adults, polycystic kidney disease is inherited and, in fact, is the most common hereditary disease in the United States. Occasionally, it occurs without a family history of the disease.
- In certain cases, urinary tract infection may cause kidney cysts.
SYMPTOMS OF KIDNEY CYSTS
- Pain or tenderness in the back or abdomen
- Blood in the urine
- Decreased kidney function
- High blood pressure
- Frequent need to urinate at night (nocturia)
- In infants, abdominal or flank masses
- Burning on urination and abdominal pain due to associated urinary tract infections
- Frequent urination, fatigue, swollen ankles, shortness of breath, and itching skin due to end-stage renal disease
- There is no known way to prevent either kidney cysts or polycystic kidney disease.
- If you have a family history of polycystic kidney disease, be sure to get regular checkups to aid in early detection.
- Patient and family history and physical examination. The doctor will press on the flanks and abdomen to detect any solid, abnormal masses.
- Blood and urine tests.
- Ultrasound or CT (computed tomography) or MRI (magnetic resonance imaging) scans of the kidneys and abdomen.
- Gene linkage analysis can detect the genetic abnormality responsible for polycystic kidney disease, but the test is expensive and rarely necessary.
HOW TO TREAT KIDNEY CYSTS
- Asymptomatic cases may benefit from modest dietary changes as well as prescription medications, in particular ACE inhibitors or ARBs (angiotensin receptor blockers).
- Antibiotics may be prescribed to treat associated urinary tract infections.
- Antihypertensive drugs are prescribed to treat associated high blood pressure.
- Rarely, needle aspiration, in which the doctor inserts a needle into the kidney to drain an enlarged or painful cyst, may be done.
- Dialysis is necessary should kidney failure occur. This procedure filters the blood artificially, removing waste products and excess fluid when the kidney can no longer perform these functions.
- A kidney transplant is an alternative to dialysis in cases of kidney failure.
WHEN TO CALL A DOCTOR
- Call a doctor if you develop symptoms of kidney cysts or polycystic kidney disease.
- Make an appointment with a doctor if you have a family history of polycystic kidney disease. Genetic counseling may be advised for those considering having children.
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media