Objective:

To determine the clinicodemographic characteristics of patients with myasthenic crisis or impending myasthenic crisis and their outcomes at 3 months. 

Background:

Myasthenia Gravis (MG) is an autoimmune disorder affecting neuromuscular transmission, with 15-20% of patients experiencing a myasthenic crisis during their lifetime. This study aims to explore the clinical characteristics and outcomes of patients presenting with myasthenic crisis or impending crisis and to assess their outcomes after 3 months.

Design/Methods:

This Ambispective observational study included MG patients in crisis or impending crisis, and a comparison group of generalized MG patients without crisis. The prospective arm included 44 patients with 52 episodes, and the retrospective arm reviewed 46 patients with 47 episodes since January 2016. Clinical profiles were collected, and MG status was assessed using the MGFA staging. Outcomes were evaluated at discharge and 3 months post-discharge using the MG-ADL score.

Results:

The mean age of the 90 patients was 42.98 ± 15.13 years, with 60% male. Generalized MG was the initial presentation in 68.89%, with ocular (16.7%) and bulbar (6.7%) forms being less common. AchR antibodies were positive in 80% of patients, and thymic abnormalities were present in 47.78%, with thymectomy performed in 79.07% of these cases. Patients with thymic abnormalities were more likely to experience three or more crises (33.3% vs. 8.6%, p=0.014). Infection significantly increased the risk of progression from impending to full crisis [OR: 5.368 (1.24, 23.19), p=0.024]. The 3-month mortality rate was 7.78%, primarily due to infection. MuSK antibody positivity was more frequent in crisis patients than in those without a crisis (8.9% vs. 0%, p=0.014).

Conclusions:

Thymic abnormalities increased the risk of recurrent myasthenic crises, while infections played a key role in progressing from impending to full crisis and were the leading cause of mortality. Anti-MuSK antibodies were an independent risk factor for myasthenic crisis in generalized MG patients.