Familial juvenile nephrophthisis; Senior-Loken syndrome
Medullary cystic disease is a hereditary disorder where the kidneys gradually lose their ability to function because of cysts in the medulla (center) of each kidney.
Causes, incidence, and risk factors Return to top
Medullary cystic kidney disease (MCKD) is very similar to the childhood disease juvenile nephronopthesis (NPH). Both lead to scarring of the kidney and formation of fluid-filled cavities in the deeper parts of the kidney (medullary cysts).
However, NPH occurs in young children and is usually due to autosomal recessive inheritance. MCKD occurs in older patients and is transmitted in an autosomal dominant pattern.
In these conditions, the kidneys don't concentrate the urine enough, leading to excessive urine production and loss of sodium. Salt supplementation may be required. Additional kidney problems follow. Most MCKD patients reach end-stage kidney disease between the ages of 30 and 50. NPH patients are about 4 years of age when it begins.
NPH may be associated with non-kidney features (like abnormalities in the eyes), while MCKD is limited to the kidneys only.
Early in the course of the disease, the symptoms include:
Need to urinate at night (nocturia)
Excessive urination (polyuria)
Low blood pressure
Need for excessive salt intake
Late in the disease, the symptoms of kidney failure may develop:
Unintentional weight loss
General ill feeling
Easy bruising or bleeding (such as vomiting blood or blood in the stool)
Decreased alertness, drowsiness, lethargy, confusion, delirium, coma
Muscle twitching or muscle cramps
Increased skin pigmentation (skin may appear yellow or brown)
Reduced sensation in the hands, feet, or other areas
Signs and tests
Early in the course, the physician may identify:
The patient is passing large amounts of diluted urine, with salt wasting.
The urine specific gravity is low and fixed.
Blood pressure may be low and require salt supplements.
The diagnosis can be established with:
Abdominal ultrasound or abdominal CT scan - these may show small kidneys or multiple cysts on the kidneys
Renal biopsy -- this may show tubulo-interstitial nephropathy and medullary cysts.
As the disease progresses, kidney failure follows:
Increasing creatinine levels
Increasing BUN (blood urea nitrogen)
Decreasing creatinine clearance
Elevated blood pressure
Anemia (shown on complete blood count)
Small, shrunken kidneys (shown on ultrasound)
Treatment Return to top
There is no cure for this disease. At first, treatment focuses on controlling symptoms, minimizing complications, and slowing the progression of the disease. Because of the loss of water and salt, the patient will need a liberal intake of both to avoid dehydration.
As the disease progresses, kidney failure develops and appropriate changes will be made:
If high blood pressure develops, anti-hypertensive medications may be needed.
Anemia may require erythopoeitin treatment to build red blood cells.
Diet will be modified to limit phosphorous- and potassium-containing foods.
Once end-stage kidney disease approaches, dialysis may be started. If a suitable donor becomes available, a kidney transplant may be performed.
There is no cure for chronic kidney failure resulting from medullary cystic disease. Untreated, it usually progresses to end-stage kidney disease. Lifelong treatment may control the symptoms of chronic kidney failure.
Hyponatremia, a disorder of fluid and electrolyte imbalance
End-stage kidney disease
Pericarditis, cardiac tamponade
Gastrointestinal bleeding, ulcers
Weakening of the bones, fractures, joint disorders
Permanent skin pigmentation changes
Changes in glucose metabolism
Changes in electrolyte levels, electrolyte abnormalities including hyperkalemia
Miscarriage, menstrual irregularities, infertility
Congestive heart failure
Calling your health care provider Return to top
Call for an appointment with your health care provider if you have any symptoms of medullary cystic disease.
This is an inherited disorder, but the way it is inherited varies. Prevention may not be possible.
Update Date: 2/11/2004
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Page last updated: 06 July 2004