Medullary cystic kidney disease

Alternative names

Familial juvenile nephrophthisis; Senior-Loken syndrome

Definition

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

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.

Symptoms

Early in the course of the disease, the symptoms include:

• Need to urinate at night (nocturia)
  
• Excessive urination (polyuria)
  
• Weakness
  
• Low blood pressure
  
• Need for excessive salt intake
  

Late in the disease, the symptoms of kidney failure may develop:

• Pale skin
  
• Weakness
  
• Unintentional weight loss
  
• Nausea, vomiting
  
• General ill feeling
  
• Fatigue
  
• Headache
  
• Frequent hiccups
  
• Generalized itching
  
• 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
  
• Seizures
  
• Increased skin pigmentation (skin may appear yellow or brown)
  
• Reduced sensation in the hands, feet, or other areas