The Spectrum of Acute Disseminated Encephalomyelitis and Mild Encephalopathy with Reversible Splenial Lesion

Abstract

Background: Acute disseminated encephalomyelitis and mild encephalopathy with reversible splenial lesion are autoimmune demyelinating disorders of central nervous system. Diagnosis remains clinical, aided by neuroimaging confirmation and excluding other causes. In the absence of a biological marker, the diagnosis of these entities based on clinical and imaging criteria could overlap.

Methods: We describe a 22-year-old woman developing mild neurological signs after an upper tract infection, a brain magnetic resonance image revealed confluent, symmetrical white matter lesions with corpus callosum involvement; after extensive ancillary testing that ruled out secondary causes we concluded that this subject had a post infectious encephalitis sharing clinical and imaging criteria for acute disseminated encephalomyelitis. However, mild encephalopathy with reversible splenial lesion could be an alternate diagnosis for this subject. Treatment with methylprednisolone completely solved both the clinical and image abnormalities without relapsing for more than 3 years of follow-up.

Conclusion: Both acute disseminated encephalomyelitis and mild encephalopathy with reversible splenial lesion share clinical and radiological features. A biological marker is needed to differentiate among these entities, since overlap is seen according to current criteria.

Figure 1

(a) Axial FLAIR showed hyperintense signal in supratentorial white matter. (b) Axial T2 showed hyperintense signal in supratentorial white matter. (c) Axial Diffusion showed restricted diffusion at the entire corpus callosum and at the white matter. (d) Sagittal T2 showed hyperintense signal in supratentorial white matter and also in the brainstem. (e) Axial T2 showed hyperintense signal at the mesencephalon. (f) Axial T2 showed hyperintense signal at the pons.

Figure 2

Axial FLAIR showed absence of abnormalities at follow up.