On the concept of myasthenic crisis.

This article reviews controversies surrounding the concept of myasthenic crisis. Literature review and our own experience demonstrate that there is disagreement about how a crisis should be defined, what the implications of a crisis are, whether crises are preventable, and how crisis incidence should be calculated. We propose that crisis be defined as weakness from acquired myasthenia gravis that is severe enough to necessitate intubation or delayed extubation following surgery. We argue that crisis need not "doom" a myasthenic patient to a different prognosis or response to therapy compared with myasthenic patients with severe generalized weakness. Finally, we argue that crisis is preventable and that crisis incidence, calculated in a standardized fashion, could be a useful outcome measure.