Introduction Respiratory failure is an uncommon association with multiple sclerosis. We report on a patient with multiple sclerosis who developed bilateral diaphragmatic weakness and type II respiratory failure requiring mechanical ventilation, who was successfully treated with plasma exchange.

Case Report A 38-year-old woman with multiple sclerosis presented in May 2009 with horizontal diplopia, lower limb stiffness and unsteady gait. Examination revealed a left sixth nerve palsy, bulbar dysarthria, lower limb hypertonia and global hyperreflexia. MRI FLAIR imaging revealed new and extensive increased signal in the pons/medulla compatible with a brainstem relapse. She received 3 days of methylprednisolone. Following completion of steroids her condition deteriorated. She became agitated, tachyapnoeic, tachycardic with paradoxical abdominal wall movements and type II respiratory failure. She had sluggish pupillary responses and vestibulo-ocular reflex, bilateral facial weakness, bulbar dysfunction and spastic tetraparesis. She was intubated and taken to ITU continuing methylprednisolone. Two failed extubations on day 2 and 5 necessitated tracheostomy. On day 6 she commenced plasma exchange in view of ongoing ventilatory support. By day 18 she had returned to the ward. In August, brainstem signs had fully resolved and repeat MRI imaging showed impressive resolution.

Conclusions Respiratory failure is a rare complication of brainstem relapses and may respond to plasma exchange.