Multiphasic disseminated encephalomyelitis (MDEM): a case report

*Correspondence: [e-mail].

Abstract

Case Presentation: A 17-year-old girl, caucasian, previously healthy, presented with several episodes of neurological deficits: August/2009: fever, headache and complete left hemiparesis, October/2009: dysarthria and impairment of extrinsic ocular motricity, August/2010: gait disorder, February/2011: headache, September/2018: seizure and dysarthria, November/2018: dysphagia, sialorrhea and slurred speech. In all events, she underwent treatment with intravenous Methylprednisolone 1g for 7 days with good recovery, and prescription of maintenance oral corticosteroid therapy. Neuroimaging exams showed lesions suggestive of a demyelinating substrate affecting the cerebral white matter, thalamus, brainstem and conus medullary. She was refferred to our center after the last episode. MOG-IgG antibody against myelin oligodendrocyte glycoprotein (MOG) was detected in serum. Intravenous immunoglobulin (IVIG) was prescribed from December/2018 to June/2019. She had no further attacks after this treatment. At last follow-up, there was a cognitive impairment (infantilized speech and school difficulties).

Discussion: MOG constitutes a quantitatively minor component of central nervous system myelin and is expressed on the outer lamella of the myelin sheath. MOG-IgG has been identified in an expanding spectrum of demyelinating syndromes specially in pediatric patients presenting with monophasic or multiphasic acute disseminated encephalomyelitis (ADEM), and optic neuritis. ADEM is the most frequent phenotype of paediatric MOG associated disease, and is characterized by encephalopathy in addition to polyfocal neurological signs. Neuroimaging exams show widespread involvement of different anatomical areas including the brainstem and spinal cord, often with longitudinally extensive transverse myelitis.

Final Comments: Although ADEM patients generally have a favorable long-term prognosis, and typically have a monophasic disease course, relapses can occur, known as multiphasic disseminated encephalomyelitis (MDEM). A relapsing course is more common in patients with persistent seropostivity and older age at onset. The second demyelinating event generally occurs in the following 12 months, but the time interval and frequency of attacks vary considerably. Every new relapse with new brain demyelination might increase the risk of secondary neuroaxonal injury, long-term cognitive impairment and post-ADEM epilepsy. Therapy for recurrent MOG-Ab-associated diseases remains a challenge, although IVIG can reduce relapse frequency.

Publication History

Article published online:
12 May 2025