The kidneys are involved in filtering waste products from the blood, which are excreted in the urine. The kidneys can occasionally develop small fluid-filled sacs called cysts. These cysts are often an incidental finding on a body scan and do not pose any medical risk, though in some cases they can cause a variety of problems in the body, including pain.
Types
There are two main types of kidney cysts, according to the Kidney Cancer Institute. A simple kidney cyst is a small spherical space within the kidney that is filled with liquid. A simple kidney cyst has no irregularities inside or on the lining of the cyst. Complex kidney cysts are defined as cysts within the kidney that have some sort of abnormality, whether it is portions with increased blood supply, small walls known as septa within the cyst or calcium deposits inside the cyst.
Symptoms and Diagnosis
In general, kidney cysts are found during a CT scan, ultrasound or MRI for other conditions, FamilyDoctor explains. Most kidney cysts do not cause any problems. If cysts become too large, however, they can lead to pain in the patient's flank, a fever and frequent urination. In severe cases a kidney cyst can lead to blood appearing in the urine.
Treatment
If a kidney cyst causes problems for the patient, there are a few ways it can be treated, the National Institute of Diabetes and Digestive and Kidney Disorders explains. The cyst can be drained using a long needle that is guided via ultrasound. Kidney cysts can also be surgically removed. The Kidney Cancer Institute explains that complex kidney cysts may need to be monitored to make sure they do not turn into kidney cancer.
Acquired Cystic Kidney Disease
In some cases cysts on a kidney can form as part of acquired cystic kidney disease, the National Institute of Diabetes and Digestive and Kidney Disorders explains. This condition is common in patients with chronic kidney disease. The development of these cysts is especially common in patients who require kidney dialysis, and the incidence increases the longer the patient is on dialysis. In many cases these cysts cause no medical problems and do not require treatment.
Polycystic Kidney Disease
Polycystic kidney disease is a genetic disorder that causes the formation of multiple cysts on the kidneys, Medline explains. This condition runs in families and causes multiple cysts to appear on both kidneys. These cysts can disrupt the kidneys' function, leading to frequent kidney infection and high blood pressure. As the disease progresses, the kidneys may produce too much of a hormone called erythropoietin, which stimulates the creation of red blood cells.
