Kidney cysts, also called renal cysts, form when fluid collects on or near the kidneys. These round pouches of fluid are usually not harmful and do not lead to other complications. Simple kidney cysts are non-cancerous, though the growths can cause some serious health disorders that weaken kidney function. These cysts differ from the cysts that form with polycystic kidney disease, an inherited disorder that enlarges the kidneys and damages them over time.
What Causes Kidney Cysts?
Doctors are not sure how or why simple kidney cysts occur. Researchers theorize the cysts develop when the surface layer of the kidney weakens and forms a pouch, called a diverticulum. The pouch fills with fluid, which later detaches and forms a cyst. Usually, there are no signs or symptoms; rather, simple kidney cysts often show up on imaging tests performed for other reasons.
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Symptoms of Kidney Cysts
Because simple kidney cysts don’t normally have any signs or symptoms, people only realize the problem when the cyst grows large enough to cause the symptoms to appear. A person with a simple kidney cyst that has grown may start feeling a dull pain in the back or side, moving into the abdomen. The pain might be accompanied by a fever.
PKD is a Serious Kidney Cyst
Polycystic kidney disease or PKD is an inherited disorder that causes clusters of cysts to develop in the kidneys. These noncancerous cysts vary in size but can grow quite large, eventually causing the organs to enlarge, damaging them. PKD is dangerous because the cysts can begin developing in the liver and other organs, and lead to high blood pressure and kidney failure.
PKD Causes Other Complications
PKD can lead to health complications including high blood pressure, extensive pain, bladder or kidney infections, blood in the urine, kidney failure, and aneurysms. Diet and exercise can help control high blood pressure in conjunction with OTC medications. Bladder or kidney infections require antibiotics. Blood in the urine, another possible symptom, may be treated by drinking lots of water to dilute the urine, preventing clots from forming in the urinary tract. In a few rare cases, PKD has caused aneurysms in people with a family history of these weak spots in blood vessels.
Is Treatment for Kidney Cysts Always Required?
Those who show no signs or symptoms may not require treatment as long for simple kidney cysts, as long as the growths do not interfere with kidney function. The cysts often go away on their own, and the doctor may recommend periodic imaging tests such as ultrasounds to catch any potential changes and dictate future treatment.
When a cyst begins to show symptoms, the doctor has several options to consider. He or she may decide to puncture the cyst and drain it. To accomplish this, the doctor inserts a long, thin needle into the skin and through the wall of the cyst. Once drained, the cyst is filled with an alcohol solution to prevent it from reforming.
If a cyst is particularly large or symptomatic, the patient may require surgery to drain or remove the growth. The surgeon will generally undertake a minimally invasive laparoscopic procedure using a tiny video camera and special tools. The walls of the cyst will be cut or burned away.
Risks of a Simple Kidney Cyst
Older adults have a greater chance of developing kidney cysts, and men contract them more often than women. An infected cyst can cause pain and fever. If a cyst bursts, it can result in severe pain in the back or side. On some occasions, kidney cyst may clog the passage of urine, leading to swelling in the kidneys.
People who have polycystic kidney disease may be able to manage their symptoms by lowering high blood pressure with prescribed medications. Blood pressure can also be regulared with good diet — low-salt choices including lots of fruits, vegetables, and whole grains — and exercise to maintain healthy weight. Smoking cessation is vital to lowering blood pressure and limiting PKD symptoms, as is minimal intake of alcoholic beverages.
Can a Kidney Cyst Turn Into Cancer?
Kidney cysts are very common, more so as people age. It is estimated more than 50 percent of people over 50 develop simple kidney cysts. In rare cases, a complex cyst forms that contains irregularities outside or within. Many complex renal cysts have a low risk for becoming kidney cancer. Doctors recommend urologist evaluation for any suspicious cysts.