Miller-Fisher Syndrome Presenting With Severe Headache and Transient Loss of Consciousness: A Case Report From Yemen.

Background: Miller-Fisher syndrome (MFS) is a rare variant of Guillain-Barré syndrome (GBS), characterized by the classic triad of ataxia, areflexia, and ophthalmoplegia. Atypical presentations involving severe headache and transient loss of consciousness (LOC) are extremely rare, posing a significant diagnostic challenge. Case presentation: We present a 38-year-old Yemeni female with hypertension, type II diabetes mellitus, and recurrent deep vein thrombosis, with no history of recent infection. She presented with an acute, severe headache lasting three days, followed by transient LOC. By the fourth day, the classic MFS triad emerged. In a resource-limited setting, diagnosis was based on the clinical triad and evidence of demyelinating polyneuropathy on nerve conduction studies (NCS), in the absence of anti-GQ1b antibody testing and normal brain neuroimaging. After receiving intravenous immunoglobulin (IVIG), the headache resolved significantly by the third dose. The patient showed improvement in ophthalmoplegia and ptosis, achieving complete neurological recovery within two months. Conclusion: Acute severe headache and transient LOC can be an early, atypical manifestation of MFS. The clinical triad and electrophysiology findings remain the cornerstones of diagnosis when antibody testing is unavailable. Early intervention with IVIG led to a successful outcome.