Abstract

Objective: Miller Fisher syndrome (MFS) is a well-recognized but rare variant of Guillain-Barre syndrome (GBS) and is typically characterized by the classic triad of ophthalmoplegia, ataxia, and areflexia. Here, we report a case with an atypical presentation of Miller Fisher syndrome that presented with an incomplete triad of ataxia and areflexia without ophthalmologia accompanied by mild proximal limb weakness and distal sensory involvement.

Clinical presentation: A 65-year-old Arab man presented with a 2-week history of acute onset progressive unsteadiness of gait, associated with headache and numbness in all four extremities. He had a history of a recent upper respiratory tract infection 2 weeks before the onset of his symptoms. He also had been vaccinated for influenza one month back. Clinical examination showed intact higher mental functions, normal cranial nerves including extra-ocular movements and optic fundi, and mild proximal muscle weakness in the lower limbs. It graded distal sensory impairment for pinprick and joint position sense. There was generalized areflexia. There was mild appendicular ataxia and definite gait ataxia. CSF analysis showed albumin cytological dissociation. A nerve conduction study revealed mixed (axonal and demyelinating) motor polyneuropathy severely affecting lower limb and cranial nerves. The Ganglioside Profile was negative for GM1 and GQ1b antibodies. He improved entirely after being treated with five sessions of plasma exchange.

Conclusion: Miller Fischer syndrome should be considered in all patients with acute-onset progressive ataxia, given its excellent response to treatment. However, a complete triad of ataxia, areflexia, and ophthalmoplegia may not be present in all patients. A high index of suspicion at presentation helps ensure proper evaluation and early treatment initiation, which can lead to excellent outcomes.