Cerebral infarction 3 weeks after intravenous immunoglobulin for Miller Fisher syndrome: a case report

Intravenous immunoglobulin is considered generally safe and is used widely as proven, and sometimes empiric, treatment for an expanding list of autoimmune diseases. Thromboembolic complications following intravenous immunoglobulin therapy are rare and there have been only five previous reports of stroke occurring within 2 to 10 days of infusion. This is the first report of cerebral infarction occurring after a longer latency of 3 weeks following intravenous immunoglobulin therapy in a patient presenting with Miller Fisher syndrome.

A previously well, 44-year-old Sri Lankan man progressively developed ophthalmoplegia, facial paralysis, ataxia and areflexia with neurophysiological and cerebrospinal fluid evidence consistent with the Miller Fisher syndrome. He made an unremarkable recovery with intravenous immunoglobulin therapy (0.4g/kg/day for 5 days, total 180g), but developed a cerebral infarct with haemorrhagic transformation 25 days later. He was noted to have a low blood pressure. Extensive investigations ruled out vasculopathic, embolic, thrombophilic and inflammatory aetiologies. Circulating intravenous immunoglobulins combined with a low blood pressure was considered the most probable cause of his stroke.

Cerebral infarction following intravenous immunoglobulin is thought to be secondary to hyperviscosity, thromboemboli, vasculitis, or cerebral vasospasm and reported to occur after a short latency when the immunoglobulin load is highest. Even though the immunoglobulin load is halved by 3 weeks, our case suggests that that the predisposition to thromboembolism persists over a longer period and may result in vascular complications if synergised with other vascular risk factors. It is recommended that intravenous immunoglobulin be infused at a rate of not less than 8 hours per day and that factors predisposing to thromboembolism such as dehydration, immobilisation and low blood pressure be avoided for the duration of at least two half-lives of immunoglobulin (6 weeks).