Myasthenic crisis: Clinical features, complications and mortality

BACKGROUND AND OBJECTIVE: Myasthenic crisis is a life-threatening complication of myasthenia gravis (MG) and when treated aggressively is associated with good outcome.
MATERIALS AND METHODS: Retrospective study of case records of patients with episodes of myasthenic crisis.
RESULTS: Twenty-one (22%) of the 95 patients with MG (9 with thymoma), experienced 23 episodes of myasthenic crisis, 3 (33%) in patients with thymoma. The crisis episodes occurred within 2 years of disease onset in 11 (52%) patients. Infection was the most common primary precipitant of the crisis occurring in 65%. The median duration of the crisis episode was 11 days (7-39 days), and the median neurological intensive care unit stay was 15 days (range 9-47 days). Fifteen (65%) episodes were treated with small volume plasma exchange (PE) and 8 (35%) episodes received intravenous immunoglobulin (IVIg). The time taken for disease stabilization, the median number of days for extubation, was 8 days (range 7-12) in the PE group and 10 days (range 7-39) in the IVIg group. Disease stabilization could not be achieved in one patient in the IVIg group. Ventilator-associated pneumonia (VAP) was the commonest complication, seen in 30%. Two (8%) of the 23 episodes of crisis were fatal, one resulting from VAP and septicemia, and the other due to crisis itself. All the 19 patients who survived to discharge had complete resolution of admission symptoms.
CONCLUSIONS: In patients with myasthenic crisis, both therapeutic options, PE and IVIg, are equally effective in disease stabilization. To achieve good outcomes all efforts should be directed at decreasing the duration of intubation and also aggressively treating the associated medical complications.

Keywords
Myasthenic crisis, plasma exchange, intravenous immunoglobulins, mechanical ventilation