3. ADEM is an acute inflammatory demyelinating disease of the CNS Is usually a monophasic disease . Onset is acute Neurological dysfunction is either multifocal or focal Most commonly effects young adults and children Prevalence 0.4 – 0.8 / 100,000 / year Sex Distribution – possible male preponderance
4. AHLE Is 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
5. ADEM Uniphasic, para/postinfections or postvaccination inflammatory demyelinating disorder of CNS AHLE Hyperacute from of ADEM, usually occuring after non-specific upper respiratory infections, more tissue destructive.
7. Chronic or recurrent forms of parainfectious or postvaccination encephalomyelitis Combined central and peripheral nervous system inflammatory demyelinating disorder Post vaccination : Rabies, influenza Post infectios : Measles
8. Common Causes of ADEM Postinfectious Viral Measles Varicella Rubella Herpes Zoster Infectious mononucleosis Bacterial Myoplasma Gram- ve organisms Salmonella typhi Protozoal Cerebral malaria
9. Post Vaccination Viral Anti rabies vaccine Influenza vaccine Small pox( vaccina) vaccine Japanese encephalitis vaccine
10. 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
11. 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
12. 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
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15. 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
16. Acute disseminated encephalomyelitis: A low power view of thoracic spinal cord stained for myelin reveals multiple foci of perivascular demyelination, some confluent.
17. CSF May be normal or show an increase in protein and lymphocytes Oligoclonal 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
18. 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
19. 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
20. Prophylaxis With measles vaccine and frequent use human diploid vaccine has drastically reduced the incidence of ADEM in India
21. 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
