A rare association of Guillain-Barré syndrome/Miller-Fisher syndrome overlap syndrome and Herpes Simplex Virus Type 1 infection: trigger or exacerbating factor?

Guillain–Barré syndrome (GBS) and its variants represent a spectrum of acute, immune-mediated polyneuropathies with heterogeneous clinical presentations and underlying etiologies. While infectious triggers are common precursors to these disorders, the association between viral infections and autoimmune neurological conditions remains an area of active investigation. Here, we report a case of GBS/Miller–Fisher syndrome overlap syndrome in an 80-year-old male presenting with dysarthria, dysphonia, ophthalmoplegia, areflexia, and postural instability following an upper respiratory tract infection. Cerebrospinal fluid analysis revealed the unexpected detection of herpes simplex virus type 1 DNA. Treatment with intravenous immunoglobulin therapy and acyclovir resulted in a progressive recovery of neurological symptoms. This case emphasizes the role of viral infections in differential diagnosis or as potential triggers for autoimmune neurological disorders highlighting the efficacy to addressed therapy in such complex cases.