The Greater Manchester Neuroscience Centre serves a population of 3.5 million. Between 1998 and 2009, 25 patients were admitted to the ITU with exacerbations of myasthenia gravis (MG), excluding those relating to thymectomy. We reviewed these patients to identify changes in MG treatment prior to admission that might explain these findings. No patient admitted to ITU was receiving azathioprine, methotrexate or mycophenolate, except for one patient with metastatic malignant thymoma. This is in spite of the commonplace use of these agents in patients in the regional MG clinic. A previous audit has confirmed the increasing use of immunosuppressive agents in MG patients within the regional clinic. Triggers for MG relapse were identified in 21 (84%) of patients. Two patients had steroid-induced deterioration in their MG. Seven had thymoma. Six were new presentations of MG. Serology was available in 20 patients, of whom 19 were seropositive. In ten patients (40%) admission to ITU was triggered by infection, however infection uncomplicated by other factors appeared to be associated with ITU admission in six of the 10 patients admitted to ITU between 1998 and 2002, but only four of the 15 admitted between 2003 and 2009. Longer duration of MG was associated with admission to ITU in the late 1990s, before the more widespread use of immunosuppressive agents. We postulate that administration of immunosuppressive agents may prevent ITU admission due to infection associated deterioration in MG.