PowerPoint Presentation By Dr.P.L.John Israel

ACUTE DISSEMINATED

ENCEPHALOMYELITISAcute Disseminated Encephalomyelitis (ADEM and its variants (modified from Francis et al)

ADEM is an acute inflammatory demyelinating

disease of the CNSIs usually a monophasic disease . Onset is acuteNeurological dysfunction is either multifocal

or focal Most commonly effects young adults and

childrenPrevalence 0.4 – 0.8 / 100,000 / year Sex Distribution – possible male

preponderance

AHLEIs a more virulent form of ADEM.Has distinctive pathological features of

tissue necrosis and hemorrhage. Both ADEM & AHLE are due to an

aberrant immune attack on the brain and / or spinal cord triggered by temporally related infections or vaccinations

ADEMUniphasic, para/postinfections or

postvaccination inflammatory demyelinating disorder of CNS

AHLEHyperacute from of ADEM, usually occuring

after non-specific upper respiratory infections, more tissue destructive.

Site restricted uniphasic ADEM (postinfectious.Postvaccination)

Transverse myelitisOptic neuritisCerebellitisBrain stem encephalitis

Chronic or recurrent forms of parainfectious or postvaccination encephalomyelitis

Combined central and peripheral nervous system inflammatory demyelinating disorderPost vaccination : Rabies, influenzaPost infectios : Measles

Common Causes of ADEM Postinfectious

Viral○ Measles○ Varicella○ Rubella○ Herpes Zoster○ Infectious mononucleosis

Bacterial○ Myoplasma○ Gram- ve organisms○ Salmonella typhi

Protozoal○ Cerebral malaria

Post VaccinationViral

○ Anti rabies vaccine○ Influenza vaccine○ Small pox( vaccina) vaccine○ Japanese encephalitis vaccine

PATHOLOGIC FEATURES A the Pathology of ADEM following

infections and vaccines is indistinguishable in each other

Grossly the brain and spinal cord are congested and swollen

They even be normal Sectioned brain on examination may show

prominent vassals in the white matter The Pathological hallmark on histology is

white spread fossae of perivenous demyelination through out the brain and spinal cord

Clinical Features Headache Vomiting Fever Confusion Meningism Focal or multifocal brain and spinal cord

signs may be present Seizures or coma may occur A minority of patients poor recover have

further episodes

Investigations MRI

Shows multiple high signal areas in a pattern similar to that of MS, although often with larger areas of abnormality.

Lesions are confluent an ill defined Usually bilateral gray matter lesions ( in thalumus basal

ganglia)Perifocal edema and mass effect may be seen There should be absence of previous demyelinating activity Follow-up MRI may reveal a status quo lesion or resolution

of lesion Any new lesion on follow up MRI is not compatible with

ADEM

MRI - Transverse myelitis: This 10-year-old girl presented with neck pain and difficulty walking. Examination revealed a C4 sensory level, hyperreflexia and paraparesis. Sagittal T2-weighted MR imaging through the cervical spinal cord shows increased caliber of the cervical cord extending from C2 to C5 and high signal intensity within the cord parenchyma

Acute disseminated encephalomyelitis: A low power view of thoracic spinal cord stained for myelin reveals multiple foci of perivascular demyelination, some confluent.

CSFMay be normal or show an increase in

protein and lymphocytesOligoclonal bands may be found in the acute

episode for do not persist upon recovery unlike in MS

The differential diagnosis from a first severe attack of MS may be difficult

Management The disease may be fatal in the acute stages

but is otherwise self limiting In general treatment should be initiated as early

as possible and as aggressive as neccesary Supportive care is of paraamount importance AHLE is uniformly fatal Treatment with high dose intravenous methyl

prednisolone with a cumulative dose of 3 – 5 gms over a period of 5days followed by a prolonged oral prednisolone tapered overed 3-6weeks

If patient does not respond adequately to steroids, intravenous immunoglobulin 0.4gms/kg body weight over 5days is given

Alternatively plasma pheresis can be considered

In very severe cases immuno suppression with cyclophospamide or mitoxantrone should be attempted

Prophylaxis

With measles vaccine and frequent use human diploid vaccine has drastically reduced the incidence of ADEM in India

Prognosis

Recovery may occur over 1- 6months 60-80% cases fully recover Rest of them may show residual

neurological signs intellectual impairment and behavioral abnormalities

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