Learning About Minimal Change Disease (MCD)

Minimal change disease (MCD) is a kidney condition. It damages the tiny filters inside the kidneys, called glomeruli. These filters keep protein in your blood. When they are damaged, protein leaks out into the urine.

The name "minimal change" comes from how the kidneys look under a regular microscope. They look nearly normal. The damage can only be seen with a more powerful electron microscope.

MCD is one of the most common causes of nephrotic syndrome. This is a group of signs that happen when the kidneys lose too much protein. MCD most often affects young children of ages 1 to 8. But it can happen in adults too.

In most cases, the cause of MCD is not known. When no cause can be found, it's called idiopathic MCD. Researchers think that the immune system may play a role, possibly attacking the kidney filters by mistake.

In some people, MCD may be triggered by a respiratory infection, allergies, or certain medicines such as nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen. Or it could be triggered by certain cancers such as Hodgkin lymphoma.

Symptoms of MCD may include:

• Swelling (edema). This is the most common symptom. It often appears around the eyes, in the ankles and feet, and in the belly.
• Foamy or frothy urine from too much protein.
• Sudden weight gain from fluid buildup.
• Fatigue or low energy.
• Urinating less than usual.
• High cholesterol.

Your doctor will start with blood and urine tests. These check for protein in the urine and see how well the kidneys are working. Adults usually need a kidney biopsy to confirm that they have MCD. But in many cases, children don't need a biopsy. During a biopsy, a small sample of kidney tissue is removed. It's then looked at under a microscope.

Under a standard microscope, the tissue looks close to normal. Under an electron microscope, the cells covering the kidney filters appear flattened. This flattening is the main sign of MCD.

Most people with MCD respond well to treatment. Corticosteroids (steroids) are the main medicine used. They help calm the immune system and allow the kidneys to heal. In children, about 8 or 9 out of 10 cases go into full remission with steroids.

Some people have relapses. This means that symptoms return after treatment ends. A second round of steroids usually works. For people who relapse often or who don't respond to steroids, medicines that suppress the immune system maybe used. Other medicines to reduce swelling, lower protein loss, and manage high cholesterol may also be used if needed.

Most people with MCD go into complete remission with treatment and don't have long-term kidney damage. Relapses are common but usually respond well to steroids again. Adults tend to relapse more often than children.

Regular follow-up with your doctor can help track kidney function and catch any relapses before they become serious.