Acute disseminated encephalomyelitis: an acute hit against the brain

In this review, the possible etiology, clinical characteristics, diagnosis, and treatment of acute disseminated encephalomyelitis (ADEM) are discussed. ADEM is a para- or postinfectious autoimmune demyelinating disease of the central nervous system and has been considered a monophasic disease. The highest incidence of ADEM is observed during childhood.

Over the last decade, many cases of multiphasic ADEM have been reported. The occurrence of relapses potentially poses a diagnostic dilemma for the treating physician, as it may be difficult to distinguish multiphasic ADEM from multiple sclerosis (MS). Many retrospective patient studies have thus focused on the clinical and paraclinical features of ADEM and have attempted to define specific diagnostic criteria. Additionally, several experimental models have provided insight with respect to the pathogenic relation of an infectious event and subsequent demyelinating autoimmunity.

Capitalizing on experience based on a large body of well characterized patient data collected both cross-sectionally and longitudinally, pharmacotherapy has been improved and mortality and comorbidities due to ADEM have been reduced. Unfortunately, the pathogenic events that trigger the initial clinical attack, and possibly pave the way for ongoing relapsing disease, remain unknown. Clinically applicable diagnostic criteria are still lacking.