Neurocritical care of myasthenic crisis

Myasthenic crisis (MC) is the most severe clinical manifestation of myasthenia gravis (MG). MC is defined as worsening MG symptoms which lead to respiratory failure and institutions of mechanical ventilation. MC is most commonly precipitated by infections (30-40% of cases). MC may occur in patients previously diagnosed but also may be the presenting event of MG. Therefore, it should be considered in every patient with respiratory failure of unknown cause particularly those with difficulty weaning off the mechanical ventilator. It is common practice to initiate a trial of noninvasive positive ventilation as a temporizing measure in patients with MG exacerbation who are expected to recover quickly and in whom immunotherapy can be instituted promptly. Once mechanical ventilation is started, patients should be treated with lung-protective ventilation (low tidal volumes, PEEP, and plateau pressures <30 cm H2O). Plasma exchange is the preferred initial treatment in the ICU to improve muscle strength and respiratory status.