Causes and Symptoms of Kidney Cyst

A simple kidney cyst is a round pouch of smooth, thin-walled tissue or a closed pocket that is usually filled with fluid. One or more may form within the kidneys. Simple cysts are the most common type of kidney cyst. They are not the same thing as polycystic kidney disease, which is a progressive disease that can lead to kidney failure. Simple kidney cysts most often do not cause harm.

Simple Kidney Cyst Causes

The cause of simple kidney cysts is not fully understood, but they do not appear to be inherited. Being male is a risk factor, however, as is age: Almost half of all people age 50 or older have one or more simple cysts in the kidneys. The size of these cysts may also increase with age and may double over 10 years.

Simple Kidney Cyst Symptoms

Simple kidney cysts usually do not cause symptoms. In most cases, a doctor finds them during an ultrasound or computerized tomography (CT) scan done for another reason. However, simple kidney cysts may:

- Cause pain in your side, back, or upper abdomen if they enlarge and press on other organs

- Bleed

- Become infected, causing fever, chills, or other signs of infection

- Impair kidney function (rare)

Simple kidney cysts have been associated with high blood pressure, but it is unclear what the relationship is between the two.