Acute Disseminated Encephalomyelitis (ADEM)
Understanding Acute Disseminated Encephalomyelitis (ADEM)
- In ADEM, as in MS, the body’s immune system mistakenly identifies its own healthy cells and tissues as foreign and attacks them. This attack causes inflammation, which damages the myelin that protects the nerves within the brain and spinal cord. Auto-antibodies directed against a component of myelin called myelin oligodendrocyte glycoprotein (MOG) are found in 36-64% of children with ADEM. Auto-antibodies are evidence of this immune attack.
- Symptoms of ADEM can come on rapidly, even within a few days. The location of the inflammation within the brain, spinal cord and optic nerves determines what symptoms may occur, including:
- Fever
- Headache (can be prolonged and severe in children)
- Nausea and vomiting
- Neurological changes including:
- Confusion, drowsiness or coma
- Numbness or tingling (sensory changes)
- Seizures
- Trouble swallowing
- Trouble with vision, often in both eyes (optic neuritis)
- Unsteady walk (ataxia)
- Weakness in the arms or legs
neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody disease (MOGAD). The process of diagnosis will include: - A medical history, including recent history of infection or vaccination
- A neurological examination of some of the above symptoms
- Brain and spinal cord magnetic resonance imaging (MRI) scans
- A lumbar puncture (spinal tap) to make sure there is no infection in the spinal fluid such as meningitis or encephalitis
- Blood tests to look for conditions such as NMOSD or MOGAD
Diagnosis requires evaluation over several months, including ruling out similar conditions like neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody disease (MOGAD). The process of diagnosis will include:- A medical history, including recent history of infection or vaccination
- A neurological examination of some of the above symptoms
- Brain and spinal cord magnetic resonance imaging (MRI) scans
- A lumbar puncture (spinal tap) to make sure there is no infection in the spinal fluid such as meningitis or encephalitis
- Blood tests to look for conditions such as NMOSD or MOGAD
- Although ADEM can appear at any age, children are more likely than adults to develop it. More than 80% of childhood cases occur in patients younger than 10 years old with the remaining cases occurring between the ages of 10 and 20. In rare cases, ADEM is diagnosed in adults. ADEM is thought to affect 1 in every 125,000 to 250,000 individuals each year. ADEM appears slightly more frequently in those assigned male at birth than those assigned female, with a male to female ratio of 1.3:1. ADEM occurs in all parts of the world and in all ethnic groups and appears more often in winter and spring.
pediatric MS onset especially in patients younger than 11 years old. - The pattern of damage seen on MRI can be different for ADEM than MS.
- Most patients with MS are treated with ongoing medications to prevent attacks. Patients with ADEM generally do not need ongoing medication.
- ADEM occurs more frequently in males. MS occurs more frequently in females.
- ADEM is more common in children. MS is more common in adults.
There are several differences between ADEM and MS:
- In most but not all cases, ADEM occurs only once. Patients with MS have further, repeated attacks of inflammation in their brain and spinal cord.
- In most cases, ADEM patients do not develop new damage on a repeat MRI scan whereas MS patients more often experience new damage on their follow-up MRI scans.
- Typical symptoms of ADEM such as fever, headache and confusion, vomiting, and seizures are not usually seen in people with MS although they can be seen in pediatric MS onset especially in patients younger than 11 years old.
- The pattern of damage seen on MRI can be different for ADEM than MS.
- Most patients with MS are treated with ongoing medications to prevent attacks. Patients with ADEM generally do not need ongoing medication.
- ADEM occurs more frequently in males. MS occurs more frequently in females.
- ADEM is more common in children. MS is more common in adults.
ADEM is a rare disease and no medications have been specifically approved by the U.S. Food and Drug Administration (FDA) to treat it. Intravenous (delivered through the vein), high-dose steroids are the standard treatment for ADEM. They are given over several days to reduce the inflammation of the brain, optic nerve(s) and spinal cord.If this therapy does not improve symptoms, the following therapies may be tried:
- Plasma exchange (PLEX) for severe attacks or if no improvement occurs with high-dose steroids.
- PLEX involves removing blood from the body through a needle and tubing.
- Through a series of steps, the plasma (the liquid part of the blood) is separated from blood cells and replaced with an artificial plasma substitute. The plasma substitute and blood cells are combined and returned to the body intravenously.
- The procedure lasts several hours and may be repeated multiple times over several days.
- Intravenous immunoglobulin (IVIG) is a treatment made from purified antibodies from healthy blood plasma donations.
- Plasma is the liquid part of the blood. The medication is given through a drip infusion through a vein in your arm and takes several hours to complete.
- IVIG has been shown to reduce the activity in certain immune diseases by decreasing inflammation.
Most children, including those with severe symptoms, make a complete or nearly complete recovery from ADEM. Most begin to feel better within days though it can take up to one year for symptoms to resolve. Some patients have minor, ongoing symptoms such as blurred vision, weakness, numbness and/or incoordination.