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Disease Profile

Acute disseminated encephalomyelitis

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset

All ages





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)



Nervous System Diseases


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]


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]


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]


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]


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

      Learn more

      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.


          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. https://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; https://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/.

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