An unusual case of Miller Fisher syndrome with unilateral 3rd nerve palsy and rapid recovery following intravenous immunoglobulin

Miller Fisher syndrome (MFS) is an immune mediated neuropathy commonly triggered by an infection. It is considered as a variant of Guillain-Barre syndrome. Although bilateral ophthalmoplegia is the commonest ocular involvement in MFS, there are reported cases of unilateral ophthalmoplegia. MFS has a benign course and treatment is not required in majority of cases unless there is a life threatening complication.

We report an unusual case of MFS, presented with isolated right sided oculomotor nerve palsy with pupillary involvement, ataxia and areflexia. Patient was treated with intravenous immunoglobulin (IVIG) achieving a remarkable recovery by five days of treatment. We believe this is a treatment effect rather than the natural course of her illness. Although it is rare, MFS should be included in the differential diagnosis of unilateral 3^rd nerve palsy with pupillary involvement, especially when associated with ataxia or areflexia. Having a low threshold to initiate IVIG in MFS may accelerate the recovery with a positive impact on patient’s functional status.