National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Acute disseminated encephalomyelitis


Other Names:
ADE; ADEM
Categories:
This disease is grouped under:
Acute disseminated encephalomyelitis (ADEM) is a neurological condition characterized by a brief but intense attack of inflammation in the brain and spinal cord. This may lead to damage of the layer of insulation around the nerves (myelin) within affected areas.[1] ADEM often follows viral infection, or less often, vaccinations for measles, mumps, or rubella (MMR).[2] Symptoms usually appear rapidly, beginning with fever, fatigue, headache, nausea and vomiting.[1] Treatment for ADEM is targeted at suppressing inflammation in the brain using anti-inflammatory drugs.[3] Most people begin to recover within days, with total or near-total recovery within a few months. Some people may have lifelong neurological impairments, and very rarely, severe cases can be fatal.[1]
Last updated: 7/26/2017
The symptoms of ADEM appear quickly, beginning with fever, fatigue, headache, nausea and vomiting, and in severe cases, seizures and coma. Damage to white matter (brain tissue that takes its name from the white color of myelin) may also occur, leading to neurological symptoms such as visual loss, muscle weakness, and difficulty coordinating voluntary muscle movements (such as those used in walking).[1]  

ADEM can be misdiagnosed as a severe first attack of multiple sclerosis (MS), since some of the symptoms of the two disorders are similar. However, ADEM usually has symptoms of encephalitis (such as fever or coma), which are usually not present in MS. In addition, in most cases, ADEM occurs only once, while people with MS have further, repeated attacks of inflammation in their brains and spinal cords.[1][2]
Last updated: 7/26/2017
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.[2][3]

Most cases of ADEM occur about 7 to 14 days after an infection, or up to three months following a vaccination.[2] 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.[4]

In many cases of ADEM, no preceding infection or "trigger" is identified.[3][2] 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.[3]
Last updated: 7/26/2017
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.[3][4] 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: 7/26/2017
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.[1]
Last updated: 8/16/2016
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.[1] 

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.[1] The risk for MS appears to be highest in children with ADEM who had no fever, triggering infection, or recent immunization.[3]
Last updated: 7/26/2017

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
MS is the main differential diagnosis. The differentiation between ADEM and a first episode of MS can be very difficult but has important prognostic and treatment implications. Differential diagnosis also includes infectious encephalitis, Guillain-Barré syndrome, glioblastoma multiforme, Schilder's disease (see these terms), psychotic disorders with acute onset, toxic/metabolic encephalopathy, vasculitis, nonvasculitic autoimmune encephalopathy, meningitis, metastatic tumor.
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Acute disseminated encephalomyelitis. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry

  • The Autoimmune Registry supports research for Acute disseminated encephalomyelitis by collecting information about patients with this and other autoimmune diseases. You can join the registry to share your information with researchers and receive updates about participating in new research studies. Learn more about registries.

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Organizations Providing General Support

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Acute disseminated encephalomyelitis. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • One of my relatives was diagnosed with acute disseminated encephalomyelitis in 1997. Due to poor medical care, he has not received consistent treatment and his health has deteriorated over the years. He is now completely paralyzed. Is it too late for treatment to be effective? What is the prognosis for an individual who has not been treated promptly? See answer


  1. NINDS Acute Disseminated Encephalomyelitis Information Page. National Institute of Neurological Disorders (NINDS). https://www.ninds.nih.gov/Disorders/All-Disorders/Acute-Disseminated-Encephalomyelitis-Information-Page. Accessed 7/26/2017.
  2. Acute Disseminated Encephalomyelitis (ADEM). National Multiple Sclerosis Society. http://www.nationalmssociety.org/What-is-MS/Related-Conditions/Acute-Disseminated-Encephalomyelitis-(ADEM). Accessed 7/26/2017.
  3. Brenton JN. Acute Disseminated Encephalomyelitis. Medscape Reference. Dec 19, 2016; http://emedicine.medscape.com/article/1147044-overview#showall.
  4. Foris L, Dulebohn S. Disseminated Encephalomyelitis, Acute. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; May 15, 2017; https://www.ncbi.nlm.nih.gov/books/NBK430934/.