BACKGROUND: Miller Fisher syndrome (MFS) is a rare variant of Guillain-Barré syndrome characterized by the classic triad of ophthalmoplegia, ataxia, and areflexia following a recent infection. Early recognition is particularly challenging due to the rarity of the condition and its tendency to mimic other common neurological and non-neurological disorders. We report a case highlighting the diagnostic and referral challenges encountered in the primary care setting.

CASE REPORT: A 38-year-old woman with no significant comorbidity presented to a primary care clinic with acute diplopia, right eye pain, headache, and perioral numbness following an upper respiratory tract infection 2 weeks earlier. Initial neurological examination was unremarkable. She was referred to the ophthalmology and emergency departments to exclude ocular pathology and posterior circulation stroke. Laboratory investigation and computed tomography of the brain were unremarkable and she was managed as a case of migraine. Meanwhile, ophthalmological review subsequently demonstrated ophthalmoplegia and the following day she developed bulbar symptoms prompting urgent neurological consultation. Repeated neurological examination revealed the classic triad of MFS. She received plasma exchange therapy following her clinical deterioration. Her neurological symptoms gradually improved with complete recovery, with residual diplopia resolving 8 weeks after symptom onset.

CONCLUSIONS: MFS remains a predominantly clinical diagnosis with subtle and evolving features that may delay recognition in the primary care setting. This case underscores the crucial role of primary care physicians in maintaining a high index of suspicion, recognizing atypical presentation, and providing appropriate safety-netting and timely specialist referral to facilitate early diagnosis and improve clinical outcomes.

Keywords: Ataxia, Guillain-Barré syndrome, Miller Fisher Syndrome, Ophthalmoplegia, Primary Health Care, Safety-net Providers