What is acute disseminated encephalomyelitis (ADEM)?
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.
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.
What are the symptoms of ADEM?
The symptoms of 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.
- 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.
How is ADEM different from 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 patients with MS are treated with ongoing medication to prevent attacks. Patients with ADEM do not require such medication.
Can a child with ADEM ever develop MS in the future?
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
What is the prognosis of 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 patients can have residual symptoms such as blurred vision, weakness or numbness.
Will ADEM affect my child's school performance?
After treatment, most children with ADEM perform as well as they ever did at school. However, some children fall behind in their school work. This could be the result of missed school days during the illness, but lingering symptoms could also be a factor.
If you notice changes in your child's school performance, it is important to let your doctors and nurses know so that they can work with the school to develop an educational plan.
Will my child get ADEM every time she has an infection?
No. In approximately 80 percent of patients, ADEM occurs only once. In some patients, it can re-occur. When it does, symptoms can be identical to the child's initial episode, but they can also be different.
It is not known why patients 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.
What will the follow-up be after my child is discharged from the hospital?
After your child is discharged from the hospital, she may need to have rehabilitation to improve her strength and balance. Some children go home and work with a physical therapist.
Your child's neurologist will check your child's brain function and perform a follow-up MRI.
Will the abnormalities on the MRI go away?
In most children, abnormalities on the MRI will significantly improve, but will not go away completely. Thus, some areas will have a small "scar." Your child's doctor will use the follow-up MRI to make sure that she doesn't develop any new abnormalities.