This document discusses Acute Disseminated Encephalomyelitis (ADEM), a demyelinating disease of the central nervous system. It is an immune-mediated condition that mostly affects children and can be triggered by viral infections or vaccinations. Patients typically experience an acute neurological deficit with symptoms like encephalopathy, weakness, or vision loss. MRI scans show multifocal white matter lesions that are often large with ill-defined borders. Treatment involves high-dose steroids, and most patients fully recover, though some cases can be multiphasic with recurrence of symptoms. It is important to follow patients over time to distinguish ADEM from other conditions like multiple sclerosis.

1. Acute Disseminated
Encephalomyelitis
presentation by
Dr.Aheed Khan

2. Demyelinating Disorders
• inherent or acquired loss of myelin sheath in both PNS
and CNS
• Causes-genetic, metabolic, infectious or autoimmune
mechanisms.
• Demyelination can result progressively in ionic
disequilibria, energy crisis, conduction block and
eventually neurodegeneration.

3. effects of demyelination
.

4. types
• Inflammatory/Immune-MS, ADEM, Optic Neuritis,SLE
• Infectious- HIV,PML,Lyme’s disease
• Granulomatous-Sarcoidosis, Wegeners
• Myelin-Metachromatic Leukodystrophy,
Adrenoleukodystrophy, Canavan disease,Alexander
disease
• Toxic/Metabolic-B12 deficiency,Cerebral pontine-
myelinolysis,radiation, PRES

5. Acute Disseminated
Encephalomyelitis
• immune mediated self-limiting, inflammatory and
demyelinating disease of CNS
• mostly affects white matter of brain and spinal cord
• acute-onset encephalopathy with neurological deficits,
typically monophasic,
• preceded by viral/bacterial infection or post-vaccination

6. .
Epidemiology
• pre-pubertal children
• winter months
• mean age 5 to 8 years, more fulminant in <2 years
• slightly male predominance
• 0.07-0.4 per 100’00 per year in paediatric population
• mortality rates- <2%, commonly in <2 years
• full recovery- 57-92% patients

7. History
• preceding infection/vaccination- absent in 1/4rth
patients
• documentation of at least 1 fever-free day from
prodromal illness s/o ADEM.
• 1-2 days to several weeks hiatus following illness
• neurological signs-mental status
change/seizure/hemiparesis/weakness in
extremities or bladder/bowel dysfunction/visual
loss/craniopathies
• posterior column abnormalities absent
• age younger than 11-12 years

8. post-vaccination history
• less than 5% follow vaccination
• rabies, hepatitis B, influenza, Japanese B encephalitis,
diphtheria/ pertussis/tetanus, measles, mumps, rubella,
pneumococcus, polio, smallpox, and varicella.
• Currently, measles, mumps, and rubella vaccination are most
often associated with postvaccination ADEM

9. Clinical Features
• fever, headache, vomiting, meningismus
• encephalopathy-characteristic feature with neurological
deficits [alteration in consciousness or behavioural
change unexplained by fever, systemic illness or
postictal symptoms]
• level of consciousness-range from subtle lethargy to frank
coma
• rapid onset encephalopathy- a/w multifocal deficits or
seizures[35% cases]

10. Neurological Symptoms
• Encephalopathy-hallmark of ADEM
• Long tract pyramidal signs like acute hemiparesis
• cerebellar ataxia
• cranial neuropathies, including optic neuritis
• spinal cord dysfunction (transverse myelitis)

11. Pathophysiology
• HPE-perivenular round cell
inflammation
• patchy demyelination with
preservation of axon cylinders
and the prominence of microglial
cells in the inflammatory exudate
• Possible Mechanism-T-helper cell
mediated Molecular mimicry to
auto-Ag
• Serum IgG to Myelin
Oligodendrocyte-
glycoprotein[MGO]- 40%-
a/w favourable outcome*
perivenular round cell inflammation
*Van Haren, K., Tomooka, B. H., Kidd, B. A., Banwell, B., Bar-Or, A., Chitnis, T., … Robinson, W. H. (2013). Serum autoantibodies to myelin peptides distinguish a

12. Examination
• Irritability & Lethargy f/b headache or meningeal signs
• Motor Defects- Weakness[75%]> Sensory Defects.
Combination~localisation
• Cranial Nerve Palsies-e.g visual loss[23-89%]
• Ataxia-appendicular>axial ot gait [28-65%]

13. Diagnosis
• Careful history and examination
• Neuroimaging
• Lab studies

14. Neuroimaging
• MRI
Brain>>CT
Scan
• T2/Flair
Images for
diagnosing
demyelinati
ng
diseases
Potential location for lesions in acquired demyelination

15. Lab findings
• no specific marker for ADEM,
• Basic Workup-CBC- thrombocytosis and Raised ESR
• CSF Examination-non-specific:
• pleocytosis-lymphocytic/monocytic
• mild elevation of CSF WBC/RBC counts
• elevated CSF protein
• Antibodies to myelin oligodendrocyte-glycoprotein, anti-N-methyl-d-aspartate receptor
• oligoclonal bands-10% ADEM; consider alternate diagnosis
• EEG- generalised slowing~encephalopathy; polyregional demyelination-focal slowing

16. MRI Features
• small punctate to tumefactive
lesions-multifocal areas of
hyperintensity on MRI
• supratentorial or infratentorial
white matter
• bilateral, asymmetrical
7 year old ADEM MRI

17. ADEM Features
• centrifugal at the junction of the deep cortical gray and subcortical
white matter
ADEM

18. ADEM Features
• additional lesions-deeper white matter-basal ganglia,cerebellum, spinal
cord
ADEM
FLAIR Image of ADEM
showing lesions
Type to enter a caption.

19. International Paediatric Multiple Sclerosis Study Group
in 2012 Definitions:
• CIS=Clinically Isolated syndrome: A first monofocal or multifocal CNS
Demyelinating event
• Monophasic ADEM:
• first polyfocal CNS event
• Encephalopathy-not explained by fever
• MRI- large,poor margins, >1-2 lesions involving Cerebral white matter
• no new symptoms or signs after 3 months
• Multiphasic ADEM: new episode after 3 months or more from 1st
episode with new or re-emergence or prior findings

20. .

21. Treatment
• Pediatric MS- methylprednisolone[20-30mg/kg/day-max
1g/day] for 3-5 days for relapses, with or without taper;
and for decreasing relapse frequency- Interferon
alpha/beta or injectable DMA-natalizumab
• NMO- Initial episodes and relapses -methylprednisolone
for 3-5 days f/b tapering. Rituximab is effective in relapses
• ADEM-high dose i/v steroids for 5 days, with oral
prednisone taper of 1 month for relapses. Follow up at 3
months for checking signs of demyelination.

22. Follow-up
• VERY IMPORTANT
• first episode-encephalopathy-ADEM-needs follow up after
3 months-complete resolution=>Monophasic ADEM. if
recurrence occurs- Multiphasic ADEM
• first episode-no encephalopathy or signs of ataxia or focal
sensory deficits, u/L loss of vision-> +/- MRI signs of
MS=> label it as CIS; keep on follow up for recurrence.
• if recurrence occurs with MRI findings consistent with MS
with CSF findings=> label it as MS

23. THANK YOU