Combined central and peripheral demyelination lies at the interface between Multiple Sclerosis and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), but remains poorly defined without standardized diagnostic criteria. Its presentation during pregnancy is infrequent, warranting special consideration given the naturally altered immune function and therapeutic constraints.

We report a 25-year-old woman, six weeks pregnant, who presented to the clinic with a 3-day history of paresthesia involving both limbs, which progressed to difficulty walking and left-leg buckling. She had experienced similar episodes in the past, including transient diplopia. Examination revealed a predominantly proximal weakness of the left leg with an extensor plantar response, a sign of upper motor neuron involvement. Nerve conduction studies indicated peripheral demyelination with severely reduced conduction velocities, absent SNAPs, and prolonged F waves. MRI of the brain showed several focal T2/FLAIR hyperintense lesions. The cervical and thoracic spines also showed multiple short-segment T2-hyperintense lesions suggestive of central demyelination. Antibody testing was negative for aquaporin-4, anti-MOG, and oligoclonal bands, but ELISA-based assays were positive for Neurofascin-140 and sulfatide IgM antibodies. These findings pointed to an immune process targeting the nodo-paranodal region. She was diagnosed with combined central and peripheral demyelination and received pulse corticosteroids. She showed full clinical recovery and is under follow-up in the clinic, with rituximab planned as maintenance therapy postpartum.