ADEM

A 19 yo male, history of hospital admission since 2weeks for headache and generalized weakness, diagnosed and treated as viral illness. CT brain normal. Csf shows raised wbc count and protein. 

Now brought to us with altered sensorium and recent onset bilateral lower limb weakness. 

On admission MRI Brain and spine for cord:

Findings:
In Brain, bilateral asymmetric multifocal T2 hyperintensities in cerebral as well as cerebellar white matter.
In spine, spinal cord show multisegemental contiguous T2 hyper intensity involving upper dorsal cord extending from C6-7 to D3-4 with focal cord swelling.

Imagingwise : Acute Disseminated Encephalomyelitis (ADEM)

Differential dignosis:
Multiple sclerosis: Lesions are relatively smaller, involves sub cortical white matter, commonly involves posterior fossa. Lesions are more symmetric. Relapsing and remetting course.
Auto immune mediated vasculitis.

ADEM is a auto immune mediated demyelination.
Age group affected is children more than adults. More common in males than female.
Variable symptoms ranging from headache fever drowsiness, CN palsy, hemi paresis, loss of consciousness and behavior changes.
5 to 15years after specific - non specific viral illness or vaccination.
Csf show leukocytosis and raised proteins, absent oligoclonal bands.
Natural histroy of disease is  usually monophasic self limitted with variable prognosis ranging from complete recovery in few weeks to a mortality of approximately 25%. Relapses are rare.