Acute disseminated encephalomyelitis


00:00 / 00:00



Acute disseminated encephalomyelitis

Nervous system

Central nervous system disorders

Spina bifida

Chiari malformation

Dandy-Walker malformation


Tethered spinal cord syndrome

Aqueductal stenosis

Septo-optic dysplasia

Cerebral palsy

Spinocerebellar ataxia (NORD)

Transient ischemic attack

Ischemic stroke

Intracerebral hemorrhage

Epidural hematoma

Subdural hematoma

Subarachnoid hemorrhage

Saccular aneurysm

Arteriovenous malformation

Broca aphasia

Wernicke aphasia

Wernicke-Korsakoff syndrome

Kluver-Bucy syndrome

Concussion and traumatic brain injury

Shaken baby syndrome


Febrile seizure

Early infantile epileptic encephalopathy (NORD)

Tension headache

Cluster headache


Idiopathic intracranial hypertension

Trigeminal neuralgia

Cavernous sinus thrombosis

Alzheimer disease

Vascular dementia

Frontotemporal dementia

Lewy body dementia

Creutzfeldt-Jakob disease

Normal pressure hydrocephalus


Essential tremor

Restless legs syndrome

Parkinson disease

Huntington disease

Opsoclonus myoclonus syndrome (NORD)

Multiple sclerosis

Central pontine myelinolysis

Acute disseminated encephalomyelitis

Transverse myelitis

JC virus (Progressive multifocal leukoencephalopathy)

Adult brain tumors

Acoustic neuroma (schwannoma)

Pituitary adenoma

Pediatric brain tumors

Brain herniation

Brown-Sequard Syndrome

Cauda equina syndrome

Treponema pallidum (Syphilis)

Vitamin B12 deficiency


Friedreich ataxia

Neurogenic bladder


Neonatal meningitis


Brain abscess

Epidural abscess

Cavernous sinus thrombosis

Creutzfeldt-Jakob disease

Central and peripheral nervous system disorders

Sturge-Weber syndrome

Tuberous sclerosis


von Hippel-Lindau disease

Amyotrophic lateral sclerosis

Peripheral nervous system disorders

Spinal muscular atrophy


Guillain-Barre syndrome

Charcot-Marie-Tooth disease

Trigeminal neuralgia

Bell palsy

Winged scapula

Thoracic outlet syndrome

Carpal tunnel syndrome

Ulnar claw

Erb-Duchenne palsy

Klumpke paralysis


Myasthenia gravis

Lambert-Eaton myasthenic syndrome

Autonomic nervous system disorders

Orthostatic hypotension

Horner syndrome

Nervous system pathology review

Congenital neurological disorders: Pathology review

Headaches: Pathology review

Seizures: Pathology review

Cerebral vascular disease: Pathology review

Traumatic brain injury: Pathology review

Spinal cord disorders: Pathology review

Dementia: Pathology review

Central nervous system infections: Pathology review

Movement disorders: Pathology review

Neuromuscular junction disorders: Pathology review

Demyelinating disorders: Pathology review

Adult brain tumors: Pathology review

Pediatric brain tumors: Pathology review

Neurocutaneous disorders: Pathology review


Acute disseminated encephalomyelitis


0 / 8 complete

USMLE® Step 1 questions

0 / 1 complete

High Yield Notes

8 pages


Acute disseminated encephalomyelitis

of complete


USMLE® Step 1 style questions USMLE

of complete

A 7-year-old boy is brought to the emergency department with 3 days of progressively worsening lethargy, irritability, and confusion. The child’s grandmother noticed the boy had trouble walking earlier in the day. He has no significant past medical history, but he recently returned from a camping trip 7 days ago. The grandmother is unable to provide further details. The patient’s temperature is 39.0°C (102.2°F), pulse is 102/min, respirations are 16/min, and blood pressure is 115/72 mmHg. Physical examination reveals a stuporous child that is arousable with sternal rub. Nuchal rigidity is absent. Ocular examination reveals intense pain with eye movements. Head MRI shows multiple lesions in the subcortical white matter, characteristic of demyelination. The patient receives proper treatment and recovers fully within a week. Which of the following is likely to be found in this patient’s history on further questioning?  


Content Reviewers

Rishi Desai, MD, MPH


Antonella Melani, MD

Tanner Marshall, MS

In acute disseminated encephalomyelitis or ADEM, acute means that the disease evolves rapidly, disseminated refers to the fact that there are multiple sites involved, encephalo- refers to the brain, myelo- refers to the spinal cord, and -itis refers to inflammation.

So acute disseminated encephalomyelitis is an autoimmune disease of the central nervous system, where there’s sudden inflammation and demyelination at multiple sites of the brain and spinal cord.

The central nervous system consists of the brain and the spinal cord.

Grossly, the central nervous system can be divided into two main areas: the grey matter, which is made up of neuron cell bodies, and the white matter, which is made up of projections from the neuron cell bodies known as axons and dendrites.

The dendrites receive electrical impulses from other neurons; the neuron cell body has all of the neuron’s main organelles like the nucleus; and finally the axons transmit electrical impulses to the dendrites of the next neuron in the series.

Some axons are surrounded by a fatty protective sheath called myelin that helps increase the speed at which electrical impulses are sent.

This myelin is produced by oligodendrocytes, which are a group of cells that support neurons.

Now, the brain is protected by harmful things in the blood by the blood brain barrier, which only lets certain molecules and cells through. For immune cells like T and B cells that means having the right ligand or surface molecule to get through the blood brain barrier, this is kind of like having a VIP pass to get into an exclusive club.

Once a T cell makes its way in, it can get activated by something it encounters.

Once the T-cell gets activated, it changes the blood brain barrier cells to express more receptors, and this allows immune cells to more easily bind and get in, kind of like bribing the bouncer to let a lot of people in.


Acute disseminated encephalomyelitis (ADEM), also called post-infectious encephalomyelitis, is a rare but serious neurologic disorder in which nerves in the brain and spinal cord become demyelinated due to an inflammation that takes place after a course of an infection.

The cause of ADEM is not well understood, but it is believed to be autoimmune-related. Symptoms come on suddenly and include headache, fever, difficulty speaking or understanding speech, weakness or paralysis of an arm or leg, double vision, seizures, and coma.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "Acute disseminated encephalomyelitis: A long-term follow-up study of 84 pediatric patients" Neurology (2002)
  5. "Acute disseminated encephalomyelitis following inactivated influenza vaccination in the Brazilian Amazon: a case report" Revista da Sociedade Brasileira de Medicina Tropical (2015)
  6. "Acute disseminated encephalomyelitis with severe neurological outcomes following virosomal seasonal influenza vaccine" Human Vaccines & Immunotherapeutics (2014)

Copyright © 2023 Elsevier, except certain content provided by third parties

Cookies are used by this site.

USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.