Emergency Conditions in the Patients with Myasthenia Gravis. Clinical Case of Complicated Course of Generalized Myasthenia Gravis after Thymthymomectomy

Abstract

Myasthenic crisis may be defined as respiratory failure or delayed extubation after surgical treatment for more than 24 hours resulting from myasthenic weakness. Myasthenic crisis results from weakness of upper airway muscles leading to obstruction and aspiration, weakness of respiratory muscles leading to reduced tidal volumes, or weakness of both muscle groups. About 1/5 of patients with myasthenia gravis experience crisis, usually within the first year of illness. Over the last four decades, prognosis from myasthenic crisis has dramatically improved from a mortality rate of 75 % to the current rate of less than 5 %. Myasthenic crisis should not be fatal, as long as patients receive timely respiratory support and appropriate immunotherapy to reduce myasthenic weakness of the respiratory muscles. In the last years there are more reports about the development of urgent conditions in patients with myasthenia gravis in the early postoperative period after thymectomy. Long-term follow-up monitoring for the study effects of thymectomy in patients with myasthenia gravis, conducted in the department of thoracic surgery of State Institution «Institute of General and Emergency Surgery named after V.T. Zaitsev of National Academy of Medical Sciences of Ukraine» showed that the incidence of early postoperative myasthenic crisis amounted 9.2–12.3 % of cases and was associated with the degree of compensation of bulbar and respiratory disorders before the surgery. This reflects the importance of an adequate selection of the dose of anticholinesterase drugs in the preoperative stage for effective compensation neurosomatic disorders and favorable postoperative prognosis. As an example, the complicated course of generalized myasthenia gravis after thymthymomectomy was described.