Lipoid nephrosis

Alternative names

Minimal change nephrotic syndrome; Nil disease; Minimal change disease; Idiopathic nephrotic syndrome of childhood

Definition

Minimal change disease is a kidney disorder. Each kidney is made of more than a million units called nephrons. Each nephron has a tuft of blood vessels called a glomerulus, which is surrounded by a Bowman's Capsule.

Together, these structures filter blood and form urine.

Minimal change disease is one cause of nephrotic syndrome. It is named "minimal change" because the nephrons appear totally normal under a light microscope. The condition is only seen using an electron microscope, which reveals changes in the Bowman's Capsule in the nephrons. Urine tests also show high protein levels.

Causes, incidence, and risk factors

Minimal change disease is the most common cause of nephrotic syndrome in children. It is also frequently seen in adults. The cause is unknown, but the disease may be preceded by viral infection, allergic reactions, or recent immunizations.

Minimal change disease does not reduce the amount of urine produced. It rarely progresses to kidney failure.

Symptoms

There may be symptoms of nephrotic syndrome:

• swelling - especially around the eyes, feet and ankles, and in the abdomen
  
• foamy appearance of the urine
  
• weight gain (from fluid retention)
  
• poor appetite
  

Signs and tests

A physical examination would not reveal much except swelling. Blood tests and urinalysis reveal results typical of nephrotic syndrome, including high levels of urine protein, low blood albumin levels, and high cholesterol.

A kidney biopsy and examination of the tissue with an electron microscope would show the classic changes of minimal change disease. An immunofluorescence exam of biopsied kidney tissue is negative.

Treatment

Swelling may be treated with diuretics, blood pressure control, and ACE inhibitor medicines. You may receive instructions on how much salt to allow in your diet.

Corticosteroids can cure minimal change disease in a vast majority of children. Some patients may require maintenance on steroids to sustain the remission.

A minority of children may relapse after they stop taking steroids. If that happens, they usually respond well to a repeat course of the steroids. Adults do not respond to steroids quite as well as children, but a majority still do find steroids effective. The frequency of relapses and steroid dependence may be greater in adults.