Comorbidities and Long-Term Outcomes in a Cohort with Myasthenic Crisis: Experiences from a Tertiary Care Center

Introduction: There is scarce literature regarding the clinical course, comorbidities and long-term outcomes after myasthenic crisis (MC). The natural history of myasthenia gravis (MG) in this subset remains uncertain.

Methods: The study included a cohort admitted with MC (2007-2017) in a tertiary care hospital. The comorbidities, outcomes after discharge, and prognostic factors were analyzed.

Results: Sixty-two patients (89 episodes of MC) were included. Demographic data was comparable between the early- (<50 years) and late-onset (≥50 years) groups. Comorbidities included stress cardiomyopathy (14.5%), arrhythmias (6.4%), neuropathy (17.7%), pancytopenia (12.9%), encephalopathy (11.2%), neuromyotonia (4.8%), myelopathy (3.2%), and myositis (3.2%). Pulmonary embolism (P < 0.008), dysautonomia (P < 0.002), sepsis (P < 0.008), neuropathy (P < 0.002), and phrenic dysfunction (P < 0.016) were associated with prolonged ventilation. Majority of the patients (42, 67.7%) had a favorable outcome (disease status) as defined by remission/minimal manifestations at the time of last follow-up (median 36 months, IQR 15-66). Persistent bulbar weakness (P < 0.001), neuropsychiatric illness (P < 0.001), and comorbidities (P < 0.017) were associated with refractory MG. Eighteen patients (29%) had recurrent crisis. Eleven patients succumbed in the cohort. The main predictors of mortality were tumor progression (P < 0.001) and cardiac illness (P < 0.004).

Discussion: A comprehensive treatment approach in MC will translate to good short- and long-term outcomes. The main cornerstones of therapy will include (1) Identification of refractory MG with the implementation of phenotype-based therapy; (2) Addressing comorbidities including cardiac autonomic neuropathy, bulbar weakness, phrenic dysfunction; and (3) Meticulous tumor surveillance.