Myasthenic crisis treated in a neurological intensive care unit: clinical features, mortality, outcomes, and predictors of survival

Background Myasthenic crisis (MC) often requires admission to an intensive care unit (ICU). Methods We retrospectively investigated 115 consecutive patients with first MC admitted to the neurological ICU. Patients’ demographic, clinical and other characteristics were examined, as well as therapeutic interventions; mortality and functional outcome. Results MC patients admitted to neurological ICU had a mortality rate of 24.34%. PCO2 level before intubation and score on Myasthenia Gravis–Activities of Daily Living (MG-ADL) scale at MC onset correlated with duration of ventilation and length of ICU stay. Compared with patients with good functional outcome, patients with intermediate or poor functional outcome were older at first MC onset, had lower pH and PO2, and had higher PCO2 before intubation. Multivariate logistic analysis identified pre-intubation PCO2 level as an independent predictor of survival. Cox regression showed that age at first MC onset requiring ICU management was the factor which significantly influenced the mortality. Conclusions: Our results suggest that PCO2 before intubation and MG-ADL score at MC onset may be useful indicators of more severe disease likely to require extensive respiratory support and ICU management. Higher pre-intubation PCO2 indicates chronic respiratory acidosis that can increase risk of severe disability and death, especially in patients with older age at first MC onset.