What is acute disseminated encephalomyelitis?
Acute disseminated encephalomyelitis (ADEM) involves a brief but intense attack of inflammation (swelling) in the brain and spinal cord that damages the brain's myelin. Myelin is the protective covering of nerve fibers. Myelin is also called white matter due to its color. Because ADEM affects myelin, it is a type of a "demyelinating" disorder.
ADEM is an "autoimmune" condition that often occurs after a child has an infection, such as a cold. The immune system protects the body from invaders, like bacteria and viruses. Autoimmune diseases confuse the body's immune system. Instead of fighting against bacteria or viruses, it attacks healthy cells and tissues.
Although ADEM can occur at any age, children are more likely than adults to have it. Most children make a complete or nearly complete recovery. The main medication for treating ADEM is a type of steroid. Most children tolerate the medication very well.
In approximately 80 percent of children, ADEM occurs only once. In some patients, it can reoccur. When it does, symptoms can be identical to the child's initial episode, but they can also be different.
It is not known why children develop ADEM with certain infections at certain times. If you notice symptoms during an infection that you think are unusual, such as confusion, changes in vision, weakness, numbness or imbalance, it is important to notify your child's doctor immediately.
How we care for ADEM
Boston Children's Hospital treats ADEM at the Pediatric Multiple Sclerosis and Related Disorders Program. Our program includes a pediatric neuropsychologist, a nurse and a social worker.
Acute Disseminated Encephalomyelitis (ADEM) | Symptoms & Causes
What are the symptoms of acute disseminated encephalomyelitis?
The symptoms of acute disseminated encephalomyelitis (ADEM) come on quickly. Your child may feel tired or irritable at first. It is also common to have a viral illness with fever a few days to a few weeks before the beginning of the symptoms. Other symptoms may include:
- nausea and vomiting
- ataxia (unsteady walk)
- sensory changes, including numbness or tingling
- optic neuritis (trouble with vision)
The location of the inflammation (swelling) within the brain and spinal cord determines what symptoms occur.
What causes ADEM?
In ADEM, the immune system reacts against the brain and spinal cord. Autoimmunity is not contagious, but may be genetic (inherited from parents). ADEM may also follow a vaccination, although this is rare. In some cases of ADEM, a specific trigger/cause cannot be identified.
Is ADEM similar to multiple sclerosis (MS)?
Both ADEM and MS involve autoimmune responses to myelin in the brain and spinal cord. They are both "demyelinating" disorders. Symptoms common to both disorders include loss of vision, weakness, numbness and loss of balance. Corticosteroids are used to treat attacks of ADEM and MS.
In most cases, ADEM occurs only once, while patients with MS have further, repeated attacks of inflammation in their brains and spinal cords. Although children can develop MS, it is much more common in adults, whereas ADEM is more common in children. Typical symptoms of ADEM such as fever, headache and confusion, are not usually seen in people with MS. MRIs are helpful when distinguishing ADEM from MS. Most children with MS are treated with ongoing medication to prevent attacks. Patients with ADEM do not require such medication.
Although it is uncommon, children who have ADEM can later develop MS. Therefore, it is important to have ongoing follow up with your our team. Let your doctor know immediately if you notice new symptoms in your child, such as:
- visual loss
- loss of balance
Acute Disseminated Encephalomyelitis (ADEM) | Diagnosis & Treatments
How is acute disseminated encephalomyelitis diagnosed?
There is not one specific test that is used to diagnose acute disseminated encephalomyelitis (ADEM). There are several exams and tests that the doctor must look at including:
- your child's medical history
- a neurological examination
- brain MRI scans
- a lumbar puncture (spinal tap) to make sure there is not an infection in the spinal fluid, such as meningitis or encephalitis
- an EEG if seizures are suspected
- blood tests to look for infectious triggers and for other conditions that can be confused with ADEM
What are the treatment options for acute disseminated encephalomyelitis?
Medications are used to reduce the inflammation (swelling) in your child's brain and spinal cord. The main medication that is used for acute disseminated encephalomyelitis (ADEM) is called methylprednisolone (Solu-medrol®), which is a corticosteroid given by IV once a day for three to five days. This medication is completely different from the illegal steroids that some athletes use.
Most children with ADEM improve with high doses of methylprednisolone. If methylprednisolone does not work, there are other treatments we use, such as plasmapheresis or intravenous immunoglobulin therapy.
Most children tolerate the steroids (the medication) very well. But in some children there are side effects such as:
- temporary moodiness or other behavioral changes
- increases in blood pressure and blood sugar, which your child's doctor or nurse will be monitoring and can treat if necessary
- irritated stomach lining
Some children will be placed on a steroid called prednisone for a short period of time. Your child may also be prescribed a medication to prevent stomach irritation.
What is the long-term outlook for a child with ADEM?
Steroid treatment can reduce some symptoms and stop new symptoms from developing. Although the long-term prognosis for children with ADEM varies, most children make a complete or nearly complete recovery, including those children with initially severe symptoms.
For most children, recovery begins within days and continues for up to one year. Some children can have residual symptoms such as blurred vision, weakness or numbness.