ABSTRACT
Acute Disseminated Encephalomyelitis (ADEM) is a demyelinating disease of Central Nervous System (CNS). It usually is followed by infection and vaccinations. It commonly occurs in the paediatric age group. Its occurrence in adults is rare. When present in adults, a diagnostic dilemma always occurs between ADEM and Multiple Sclerosis (MS), because of overlapping clinical, and neuroimaging features. We present a case of a 46 year old female who presented to us with variable neurologic manifestations and later was diagnosed with ADEM. This case tries to embark on arguments so as to differentiate ADEM from MS while dealing with such cases.Acute Disseminated Encephalomyelitis (ADEM) and Multiple Sclerosis (MS) are both considered as immune mediated inflammatory demyelinating diseases of the central nervous system.1,2 Although considered as different conditions, the clinical presentation of both these conditions may overlap. The only gold standard differentiation is pathologically determined. Perivenous demyelination is a feature of ADEM and discrete confluent demyelination (plaque) is signature of MS. Still hybrid cases showing pathological features of both ADEM and MS may co-exist.ADEM, typically though not always is preceded by some infection or vaccination. The course of ADEM is usually monophasic and prognosis is better than MS which commonly presents with a relapsing and remitting course. Each exacerbating event worsens the clinical course in MS. Different clinical and/or radiological criteria to differentiate between the two spectrums of diseases have been proposed, but none of those unequivocally differentiate them.Hartung and Grossmann hypothesized that ADEM may be a part of the MS spectrum, rather than a different entity.3 The characteristic demyelination in ADEM is perivenous as opposed to MS where the demyelination is confluent. 4Acute Disseminated Encephalomyelitis (ADEM) is a demyelinating disease associated with inflammation and demyelination of the Central Nervous System (CNS) in a monophasic pattern. ADEM occurs commonly in paediatric age group often following viral infections, bacterial infections, or vaccinations.[5,6] The clinical characteristics include a sub-acute development of focal neurologic deficits, accompanied by encephalopathy. 5,6 It can rarely occur in middle-aged or elderly adults. The course is usually fulminant, but typically there is recovery in 50–75% of cases, with progression to multiple sclerosis in up to 20% of cases.[5,6]