Kidney cysts are abnormal, round bags filled with fluid and are present in and on the kidneys. These cysts can impair the kidney function if they grow large. However, most of the cysts are considered as simple kidney cysts which are non-cancerous and may rarely cause any complications.
These simple kidney cysts are different from the cysts that result in polycystic kidney disease (PKD). Simple kidney cysts do not cause structural changes in the kidneys as seen with PKD.
Person with simple kidney cysts does not show any symptoms. The symptoms mentioned below usually develop after these cysts grow large in size:
- Mild pain in the sides and back
- Upper abdominal pain
The exact cause for the formation of kidney cysts is not yet clear. However, it is believed to develop in the weakened portions of the kidney surfaces. This converts into a pouch which gets filled with fluid and detaches itself from the surface to form a cyst.
Also, the cysts may develop due to the obstruction of tubules within the kidneys or if the blood supply to the kidneys is not adequate. Simple kidney cysts do not have a genetic origin.
The risk of developing kidney cysts is more in men when compared to women.
It can occur at any age but is relatively more commonly seen in old age. Nearly 25% of people aged above 40 years and about 50% of people aged above 50 years are detected with simple kidney cysts.
The following are the tests performed for the diagnosis of kidney cysts:
Tests which create the images of the kidneys such as a computerized tomography (CT) scan, an ultrasound or a magnetic resonance imaging (MRI) are most commonly used. These tests help the physician to differentiate a cyst from a kidney mass or tumor.
Blood tests may be carried out to know if the kidney function is normal or impaired due to the presence of cysts.
Occasionally, kidney cysts are detected when the above tests are carried out for some other reasons.
The treatment for simple kidney cysts is based on the severity of the cysts. If they are small and do not produce any signs or symptoms and do not interfere with the kidney function, then treatment is not required. However, the doctor will suggest the patient for regular follow up visits to check for changes in the size of the cysts.
If the cysts grow large and the person starts showing the signs and symptoms, then treatment is needed. Treatment options for kidney cysts are:
- Cyst puncture and refilling – after giving local anesthesia, the doctor inserts a thin, needle through the skin into the cyst wall to puncture it. The fluid from the punctured cyst is drained, which is later filled with alcohol to prevent the formation in future. In general, this procedure is performed on an outpatient basis.
- Surgical removal – if the size of the cyst is too large, then it can be drained only by surgical approach. The surgeon makes small incisions on the skin to insert the video camera and the required surgical tools. While watching the inside of the kidneys, the surgeon guides certain specialized tools to empty the fluid from the cysts. These empty cysts are then burned away to prevent reformation. Recovery after this surgery does not take too long as the incisions are small in size.
Occasionally, if the kidney cysts are left untreated, it can lead to the following complications;
- Infection of the cyst which causes pain and fever
- Bursting of the cyst which causes severe pain on the sides or on the back
- Obstruction of the urine flow which can result in swelling of the kidneys