Acute disseminated encephalomyelitis

What causes acute disseminated encephalomyelitis (ADEM)?

The cause of ADEM is not clear. It is thought to be an autoimmune condition in which the body’s immune system mistakenly attacks it's own cells and tissues, resulting in inflammation. It typically develops after a viral or bacterial infection, or less often, after vaccination (immunization). ADEM may occur due to an inflammatory response that is first provoked by the infection or vaccine.

Most cases of ADEM occur about 7 to 14 days after an infection, or up to three months following a vaccination. The most commonly associated infectious agents include cytomegalovirus (CMV), Epstein-Barr virus, herpes simplex virus, human herpes-virus-6, influenza virus, hepatitis A, HIV, and mycoplasma pneumonia. Associated vaccines have included rabies, measles, pertussis, tetanus, influenza, hepatitis B, diphtheria, rubella, pneumococcus, varicella, smallpox, human papillomavirus and poliomyelitis.

In many cases of ADEM, no preceding infection or "trigger" is identified. Susceptibility to having ADEM may exist and is likely due to multiple factors, including complex interactions between genetics and exposure to infections and other environmental factors.

Last updated on 05-01-20

Is acute disseminated encephalomyelitis (ADEM) inherited?

ADEM is not an inherited condition, and we are not aware of any familial cases (reports of ADEM occurring in more than one family member). However, some people may be more susceptible to having ADEM. Susceptibility is likely due to multiple factors, including complex interactions between genetics, exposure to infections, immunization exposure, and other environmental factors. Because there are no specific genes known to increase a person's risk to have ADEM, there is no "susceptibility" test for children who may be at risk, or for parents concerned that current or future children may be at risk. You can read about what is known about possible causes of ADEM here.

Last updated on 05-01-20

What is the long-term outlook for people with acute disseminated encephalomyelitis (ADEM)?

The long-term outlook (prognosis) for people with ADEM varies. Most people begin to recover within days, with total or near-total recovery within a few months. Rarely, there may be some lifelong neurological impairment. Very rarely, ADEM can be fatal.

ADEM may recur in some cases, and if it does, it is usually within months of the initial episode. Recurrences are typically treated by restarting corticosteroids. A small proportion of people initially diagnosed with ADEM will go on to develop multiple sclerosis (MS). Unfortunately, there is no way to predict who will develop MS. The risk for MS appears to be highest in children with ADEM who had no fever, triggering infection, or recent immunization.

Last updated on 05-01-20

What is the prognosis for individuals with acute disseminated encephalomyelitis (ADEM) who do not receive treatment in a timely manner?

Early treatment one of the most important factors to determine the prognosis for individuals with ADEM. However, it is not known whether any available form of treatment effects the time to recovery or the risk for complications.

Last updated on 05-01-20

How might acute disseminated encephalomyelitis (ADEM) be treated?

Treatment for ADEM aims to suppress inflammation in the brain. Treatment is usually comprised of anti-inflammatory medications. Most individuals respond well to intravenous corticosteroids, such as methylprednisolone. When corticosteroids fail to work, plasmapheresis or intravenous immunoglobulin therapy may be utilized.

Last updated on 05-01-20

Is it too late to start proper treatment in order to reverse or stabilize my relative's health?

Although we haven't been able to locate any studies which discuss the usefulness of delayed treatment, corticosteroid therapy has been shown to shorten the duration of neurological symptoms and halt further progression of the disease in general. We recommend that you discuss your concerns with a healthcare provider familiar with the details of your relative's case.

Last updated on 05-01-20

Where To Start

Cleveland Clinic - ADEM

The Cleveland Clinic provides information about acute disseminated encephalomyelitis (ADEM). Click on the above link to access information on this topic.

Last updated on 04-27-20

National Multiple Sclerosis Society - ADEM

The National Multiple Sclerosis Society provides information on acute disseminated encephalomyelitis (ADEM). Click on the above link to access information on this topic.

Last updated on 04-27-20

Siegel Rare Neuroimmune Association

The Transverse Myelitis Association provides information about acute disseminated encephalomyelitis (ADEM).

Last updated on 04-27-20

Name: National Multiple Sclerosis Society 733 Third Avenue, 6th Floor
New York, NY, 10017-3288, United States
Phone: +1-212-986-3240 Toll Free: 1-800-344-4867 Fax : +1-212-986-7981 Email: Url:
Name: United Leukodystrophy Foundation (ULF) 224 North Second Street Suite 2
DeKalb, IL, 60115 , United States
Phone: 815-748-3211 Toll Free: 800-728-5483 Fax : 815-748-0844 Email: Url:
Name: Siegel Rare Neuroimmune Association SRNA 1787 Sutter Parkway
Powell, OH, 43065-8806, United States
Phone: +1-614-317-4884 Toll Free: 1-855-380-3330 (Helpline) Email: Url: (Formerly the Transverse Myelitis Foundation)
Name: American Autoimmune Related Diseases Association (AARDA) 22100 Gratiot Avenue
Eastpointe, MI, 48021, United States
Phone: 586-776-3900 Toll Free: 800-598-4668 Fax : 586-776-3903 Email: Url:
Name: Autoimmune Encephalitis Alliance 920 Urban Avenue
Durham, NC, 27701,
Email: Url:

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