Acute disseminated encephalomyelitis (ADEM) is a rare inflammatory condition treated at Great Ormond Street Hospital (GOSH), that affects the brain and spinal cord. It often follows on from a minor infection such as a cold and is a result of the immune system becoming mis-programmed and activating immune cells to attack the healthy myelin covering the nerves.
What are the signs and symptoms of ADEM?
ADEM usually comes on quite quickly over hours to days. Symptoms may include nausea and vomiting, headache irritability and sleepiness, unsteadiness or inability to walk, problems with vision, weakness or tingling in certain areas of the body. In severe cases seizures can result. The symptoms depend on where in the brain or spinal cord the inflammation and swelling is occurring.
How is ADEM diagnosed?
ADEM can be difficult to diagnose and often needs specialist tests. It is also important for the doctors to consider other possible causes of inflammation and infection. To exclude these, bloods tests and a lumbar puncture may need to be carried out. A lumbar puncture involves taking a tiny amount of cerebrospinal fluid (the fluid which surrounds the brain and spine) from the bottom of your spine. This is to check for the presence of particular proteins that might indicate inflammation.
An MRI scan of the brain (and sometimes the spine) will be the most helpful in making the diagnosis. An MRI scan uses a magnetic field to take pictures of the brain and spine. It will enable the doctor to see whether the myelin around the brain and spinal cord has been damaged. Sometimes a dye (contrast) will need to be given intravenously (into a vein using a needle) during the scan, to help see the areas involved more clearly. Treatment for other causes, such as brain infection (encephalitis), may be started before this is done.
How is ADEM treated?
Steroid treatment can reduce some symptoms and stop new symptoms from developing. Once the diagnosis is made, they are usually given into a vein once a day for the next three to five days. Most young people start to get better quickly, and make a full recovery. If though there is no sign of improvement within a few days, other treatments may need to be considered.
What is the prognosis of ADEM?
For most children, recovery begins within days and continues for up to one year. Some patients continue to have symptoms such as blurred vision, weakness or numbness.
Will my child get ADEM again?
ADEM usually only occurs once, sometimes twice. Multiple attacks are very rare so may require further tests and discussion to confirm the diagnosis.
Will my child go on to develop multiple sclerosis (MS)?
ADEM and MS are both conditions being caused by the body’s immune system becoming mis-programmed and attacking the myelin covering of the central nervous system. A small number of children with ADEM will go on and develop further attacks and possibly MS. However, the typical features seen in ADEM of sleepiness, irritability and fever are uncommon in a first attack of MS. Your doctor will be able to discuss this with you based on your child’s specific symptoms and MRI findings. You may also be asked to help in research to enable us in time to answer these questions better.
What happens next?
Once the team looking after your child feels that the time is right, you will be discharged either to your local hospital or home. If there are no new concerns, your local paediatrician will continue to care for your child. If there are any new concerns, we would be happy to see you back in a clinic at GOSH.
We suggest any routine vaccination is delayed if possible for at least six months after the ADEM attack, but clearly this needs to be balanced against the risks of being unvaccinated.