Hemiparesis and homonymous hemianopia as the presenting sign of multiple sclerosis

Abstract

We report two young patients presenting with acute homonymous hemianopia and acute severe hemiparesis involving the face. The diagnostic work-up led to the diagnosis of multiple sclerosis.Clinically symptomatic retrochiasmal demyelinating lesions are rare even in the long-term course of multiple sclerosis and those affecting the pyramidal tract usually produce only mild partial dysfunction with bilateral symptoms due to brainstem or spinal cord involvement. Acute homonymous hemianopia or motor hemiparesis first suggest another etiology than multiple sclerosis, particularly a vascular lesion. MRI is the investigation of choice in this clinical setting, showing an unusually large lesion in most cases where a demyelination is the cause. Clinical recovery nevertheless is usually excellent, despite persistence of the lesion on repeated imaging. This contrasts with that of an infarction and also with that of acute monophasic demyelinating disease (Marburg, Balo), variants of multiple sclerosis that need to be considered initially.