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 structure called the Bowman's Capsule. Together, these structures filter blood and produce urine.

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

Alternative Names

Causes

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

Exams and Tests

The doctor would not be able to see any obvious outward signs of the disease, other than swelling. But blood tests and urinalysis would 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 (water pills), 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 need to stay on steroids to keep the disease in remission.

Some 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.

Frequent relapsers (more than 3 relapses) may need cytotoxic therapy. In most cases, this involves a course of cyclophosphamide. Other medicines that have been used include cyclosporine and chlorambucil.

Outlook (Prognosis)

Minimal change disease usually responds well to corticosteroids, usually within the first month. Relapse may occur but the patient may benefit from prolonged treatment with corticosteroids and immunosuppressive medications.

Possible Complications

• side effects of medications
• nephrotic syndrome

When to Contact a Medical Professional

Call for an appointment with your health care provider if symptoms of minimal change disease occur.

If you have this disorder, call for an appointment with your health care provider if symptoms worsen or new symptoms develop, including side effects of medications used to treat the disorder.

Prevention

There is no known prevention.

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