Acute Disseminated Encephalomyelitis (ADEM)

Acute disseminated encephalomyelitis (ADEM) is a disorder in which the immune system causes an intense attack on the brain, and sometimes the spinal cord and the optic nerves. Often ADEM follows viral or bacterial infections, although it is uncommon to find a specific infection.

ADEM is rare, affecting 1 in every 125,000 to 250,000 people worldwide each year. Children under 10 are more likely to be affected than older children and adults. It appears slightly more often in males.

In most cases, ADEM is monophasic, meaning it only occurs once in a lifetime, but in some patients is can be the first attack of a relapsing disease.

The symptoms of ADEM usually develop over the course of one or two days.

The symptoms of ADEM include one or more of the following:

• Fever
• Fatigue
• Headache
• Nausea or vomiting
• Confusion or reduced level of awareness which can be severe (also called encephalopathy, which is a required symptom for diagnosis)
• Impaired coordination
• Unsteady gait (walking difficulties)
• Numbness or tingling
• Weakness
• Bladder involvement (problems with urination)
• Optic neuritis (changes in vision)
• Seizures
• Behavioral changes (irritability or altered consciousness)

ADEM is an autoimmune disease in which the body mistakenly attacks its own brain tissue and sometimes the spinal cord and/or optic nerves as well. ADEM usually occurs following an infection, with symptoms appearing 7 to 14 days after a cough, sore throat, or gastroenteritis.

A diagnosis of ADEM is made in children with encephalopathy (reduced level of consciousness or major changes in behavior, or profound irritability) and neurological deficits (as listed above in signs and symptoms).

Imaging studies (MRI) of the brain and spinal cord typically show multiple areas of inflammation.

A lumbar puncture is typically required to rule out active infection, and many patients receive antibacterial and antiviral therapies until the spinal fluid analysis is completed and found to be negative for infection. 

ADEM is treated using medications that reduce the inflammation. The most common treatment is corticosteroids administered intravenously.

Other treatments for ADEM can include intravenous immune globulin (IVIG), which involves infusions from healthy blood donors, or plasmapheresis, a process in which the blood is filtered through a machine to remove the antibodies causing the autoimmune response.

Most children with ADEM begin to recover rapidly with treatment. The majority recover fully or near fully, typically within a week but almost all within six months of the attack. A few may have lasting mild or moderate impairments, such as cognitive changes, vision damage or muscle weakness.

Rarely, children with ADEM experience another attack of the immune system on the brain (i.e. another ADEM attack, or other symptoms), optic nerves (optic neuritis), or spinal cord (transverse myelitis).

In some children, these recurrences may lead to a new diagnosis, such as multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), or myelin oligodendrocyte glycoprotein (MOG) related demyelination.

At Children’s Hospital Philadelphia (CHOP), your child will see an experienced team of experts who specialize in demyelinating diseases like ADEM. We have been caring for children with ADEM for more than 15 years and have the knowledge, tools, and supports to provide world-class care for your child.

We partner with other specialties within CHOP such as ophthalmology, urology, pain management and neuropsychiatry to coordinate your child’s care as necessary.

At Children’s Hospital of Philadelphia, we are actively engaged in research to better understand the causes and identify more effective treatments for ADEM.

If you or your child are interested in participating in or learning more about our research studies, please email brainresearch@email.chop.edu.