Polycystic Kidney Disease (PKD) & Other Types of Kidney Cysts

Kidney cysts are not common, but left untreated, they can cause damage that leads to eventual renal failure. Kidney cysts are usually caused by inherited genetic disorders. They require lifelong treatment: Cures for the disorders are currently unavailable.
Polycystic Kidney Disease
Polycystic kidney disease, or PKD, affects over 500,000 Americans, and is the fourth leading cause of renal failure. It is an inherited disorder that causes a gradual deterioration in renal function. The organs slowly enlarge as fluid-filled cysts build up. The enlarged organs cause discomfort and pain along the sides of the body.

The severity of PKD varies among individuals. Some cases are mild, but more than half eventually require dialysis or kidney transplant. PKD complications include a heightened risk of hernias, kidney stones, and infection. In rare cases, the disorder can cause brain aneurysms. Because no cure for PKD exists, treatment concentrates on slowing the progression of the disease and providing relief from symptoms.

Polycystic kidney disease pain can be traced to the pressure caused by the enlarged kidney. Infections of the fluid in the cysts and the presence of kidney stones can also cause pain. Over-the-counter medication may provide relief. Surgery to shrink the cysts is available. Surgical pain relief is temporary, however, as cysts eventually grow back.

Symptoms of polycystic kidney disease include:

  • diverticulosis (the formation of small sacs in the colon)
  • headaches
  • heart valve deformities
  • hematuria (blood in the urine)
  • hypertension
  • liver and/or pancreatic cysts
  • pain in the back or sides
  • renal stones
  • urinary tract infections.

Medullary Cystic Kidney Disease (MCK)

Medullary cystic kidney disease, like PKD, is a hereditary disorder. The genetic information responsible for MCK is carried on the X-chromosome. Men may inherit the disorder from their mothers. Women can potentially develop medullary kidney cysts only if both parents carry the MCK genes.

Medullary kidney cysts develop in the medulla, the center of each organ. Kidney function gradually diminishes, and can eventually result in complete renal failure. MCK is characterized by an inability to concentrate urine. As a result, excessive fluid and sodium loss occur. Treatment usually includes increased fluid intake and a low protein, high carbohydrate diet.

Possible signs of medullary kidney cysts include:

  • excessive urine production
  • pale-colored urine
  • nocturia (nighttime urination)
  • nausea and vomiting
  • weight loss
  • frequent attacks of hiccups
  • easy bleeding and/or bruising
  • loss of mental alertness
  • yellow-brown tone to the skin.

Medullary Sponge Kidney (MSK)

Medullary sponge kidney (MSK) is a rare congenital disorder — a condition that is present at birth as a result of environmental influences or hereditary factors. One out of every hundred people has some degree of MSK.

MSK usually produces no symptoms until adulthood. The small tubes that drain urine into the ureters are dilated. The kidney's tubes fill with liquid or solid cysts. This causes urine to pool throughout the kidney, leading to heightened risk of infections and kidney stones. MSK can be inherited, but more often the cause is unknown.

Kidney infection or the development of kidney stones cause fever and flank pain. Treatment of symptoms is required to avoid kidney damage and possible loss of function. Antibiotics are used to control infection, and surgery removes large stones.

Symptoms of medullary sponge kidney include:

  • fever
  • back and side pain
  • frequent urination
  • pain while urinating
  • cloudy urine
  • hematuria.

Resources

National Kidney and Urologic Diseases Information Clearinghouse. (2002). Polycystic kidney disease [NIH Publication No. 02-4008].

Polsdorfer, J.R. (2001). Medullary sponge kidney. Gale Encyclopedia of Medicine.

Turner, N. & Watson, M. (updated 2002). Polycystic kidney disease. Renal Unit of the Royal Infirmary of Edinburgh.

U.S. National Library of Medicine. (updated 2004). Medullary cystic kidney disease. MedlinePlus Medical Encyclopedia.