Objectives To evaluate the management of myasthenic crisis (MC) and to analyse the risk factors for prolonged mechanical ventilation.

Methods Retrospective review of consecutive patients admitted for MC between January 1994 and December 2011 in the First Affiliated Hospital of Sun Yat-sen University. Risk factors for prolonged mechanical ventilation were analysed retrospectively by age, gender, autoimmune disease, ischemic heart disease, disease duration, precipitating factor, thymoma, pneumonia, atelectasis, high-dose corticosteroid therapy and bacteremia.

Results We identified 53 episodes of MC in 38 patients. Five patients died during hospitalisation, the success rate was 90.6%. In the univariate analysis, age (P = 0.024), infectious causes (P = 0.007), concurrent atelectasis (P = 0.011), pneumonia (P = 0.027) and bacteremia (P = 0.046) were significantly related to prolonged mechanical ventilation, while age (P = 0.035), concurrent atelectasis (P = 0.042) and pneumonia (P = 0.025)were statistically significantly linked with prolonged mechanical ventilation in the multivariate analysis.

Conclusions Timely opening the airway and applying appropriate mechanical ventilation is the key to successful emergency treatment for MC; plasma exchanges or intravenous immunoglobulin can markedly improve the outcome of MC; elder, concurrent atelectasis and pneumonia are the risk factors for prolonged mechanical ventilation.