Multiphasic acute disseminated encephalomyelitis (MDEM) in a patient with systemic lupus erythematosus and C4A deficiency: case-based review.

Acute disseminated encephalomyelitis (ADEM) is a fulminant inflammatory demyelinating disorder of the central nervous system, typically triggered by an aberrant immune response to infectious agents or vaccination. While ADEM is primarily observed in the pediatric population, it can also develop in adults; however, the precise host factors that increase susceptibility to ADEM remain poorly understood. Although ADEM has occasionally been reported in association with systemic lupus erythematosus (SLE), we present, to our knowledge, the first documented case of multiphasic ADEM in a patient with monogenic SLE caused by a homozygous frameshift mutation in the C4A gene. Herein, we provide a comprehensive literature review focusing on clinical manifestations and therapeutic approaches for ADEM and its multiphasic variants in SLE. Moreover, we propose a potential pathophysiological link between inherited C4A deficiency and susceptibility to central nervous system demyelination, offering novel insight into mechanisms underlying the development of ADEM in the context of SLE.