Acute Disseminated Encephalomyelitis (ADEM)

ADEM is a rare kind of inflammation that affects the brain and spinal cord. It damages the protective coating of nerve fibers, called myelin. Most often, children under age 10 will get it.

While symptoms can be severe, they can be treated. Most people make a full recovery and don't have another attack.

Symptoms

ADEM comes on suddenly and gets worse fast.

When their myelin is damaged, nerves can't pass signals correctly. That can cause muscle weakness and problems with balance and moving smoothly. You may have trouble seeing if ADEM attacks the myelin on the optic nerve, which sends signals from your eyes to your brain.

Other symptoms include:

Causes

ADEM seems to be an autoimmune disease. That means your immune system attacks your body's own cells and tissues as if they were outside bacteria or viruses.

Experts don't know exactly what triggers it, but it could be an overreaction to an infection. Most of the time, the attack happens when a child is getting over some common illness, like a cold or stomach bug.

ADEM sometimes follows an immunization, particularly certain rabies shots and the vaccine for measles, mumps, and rubella. No direct connection has been made though.

Other times, nothing out of the ordinary happens before symptoms appear.

Diagnosis and Tests

No one test proves you have ADEM, but doctors most often use MRI (pictures of the brain made with a large magnet and radio waves) and a lumbar puncture (fluid drawn from around the spinal cord and then tested) to help diagnose it.

The condition has a lot in common with multiple sclerosis and other diseases that damage myelin. They share some symptoms, like muscle weakness, numbness, loss of vision, and loss of balance.

But MS is rare in children. Other differences can also help your doctor make the right diagnosis.

  • Kids with ADEM may have a fever, a headache, seizures, or trouble thinking clearly.
  • The disease usually appears soon after a viral illness. There's no such link with MS.
  • An ADEM attack usually happens once, while multiple sclerosis involves many episodes over time.
  • Tests of spinal fluid usually show certain proteins when you have MS, but not ADEM.
  • With ADEM, spinal fluid usually has more white blood cells than normal.
  • Damage to the brain from ADEM and damage caused by multiple sclerosis look different on an MRI. It's more widespread with ADEM.

The doctor has to rule out other illnesses with similar symptoms, too, like infections of the brain and spinal cord such as meningitis.

Continued

Treatment

The goal is to get the inflammation down quickly and stop the immune system attack. This will likely take a week or two in the hospital.

Most people start with high doses of a powerful corticosteroid by IV for a few days. Your child may feel better within hours. They'll continue to take a steroid (as a pill or a liquid) for several weeks, in smaller and smaller doses.

If your child can't have steroids or if they don't work, some procedures can calm the immune system. The doctor may filter their blood through a machine to remove the antibodies that their immune system is sending to attack the brain. This is called plasmapheresis. Or they could get shots of antibodies from a healthy person, which is called intravenous immunoglobulin treatment.

After the hospital, they may need some combination of physical, occupational, and speech therapy. They may have to stay in a rehab hospital for a while, or maybe they can go home and work with a therapist.

Your child's doctor will probably want a follow-up MRI to make sure the inflammation is gone and no new scars have formed.

Outlook

Most of the time, a child who gets ADEM will recover completely. It will be a slow process, over 4 to 6 weeks. But it could be 6 months or up to a year before they're fully well.

In some cases, kids don't get over all of their symptoms. They may have lasting vision damage or muscle weakness. They might have trouble in school if they've missed a lot of time, or perhaps as a lingering effect of the attack.

About 8 times out of 10, ADEM happens only once. But sometimes you can get it again within a few months, especially if you don't take steroids for long enough.

Your child might get MS later, but it's unlikely.

In very rare cases, ADEM can be fatal.

WebMD Medical Reference Reviewed by Neil Lava, MD on May 27, 2016

Sources

SOURCES:

National Institute of Neurological Disorders and Stroke: "NINDS Acute Disseminated Encephalomyelitis Information Page."

Medscape: "Acute Disseminated Encephalomyelitis."

The Transverse Myelitis Association: "Disease Information."

National Multiple Sclerosis Society: "Acute Disseminated Encephalomyelitis (ADEM)."

Children's Healthcare of Atlanta: "Acute Disseminated Encephalomyelitis (ADEM): Patient and Family Education."

National Organization for Rare Disorders: "Acute Disseminated Encephalomyelitis."

Cleveland Clinic: "Acute Disseminated Encephalomyelitis (ADEM)."

Boston Children's Hospital: "Acute Disseminated Encephalomyelitis (ADEM) Testing and Diagnosis," "Pediatric Multiple Sclerosis And Related Disorders Program at Boston Children's Hospital," "Treatments for Acute Disseminated Encephalomyelitis (ADEM) in Children," "Acute disseminated encephalomyelitis (ADEM) symptoms & causes in children."

UpToDate: "Acute disseminated encephalomyelitis in children: Treatment and prognosis."

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