Myasthenic crisis is a potentially life-threatening complication of MG in which the respiratory muscles become too weak to support adequate breathing or the ability to swallow is lost. This is most commonly brought on by a respiratory infection or a change in medication. Myasthenic crisis is most likely to occur in a person who already has weak oropharyngeal muscles, and may be preceded by increased difficulty swallowing, speaking or coughing. The onset of a crisis is marked by shortness of breath and difficulty breathing or coughing. If patients are adequately treated during the course of MG, myasthenic crisis is rare.
Myasthenic crisis requires emergency medical attention.
Intubation may be needed for one to two weeks or more. Drug treatment is used to rapidly improve weakness, and often includes either plasmapheresis or IVIg treatment. Most people with MG who receive good medical care are able to lead full, productive lives. The maximum degree of weakness occurs in the first year for about two-thirds of patients. Most people are able to effectively control their symptoms, although some residual weakness may occur in the most severely involved muscles.