UNASSIGNED: Thymectomy is an efficient and standard treatment strategy for patients with myasthenia gravis (MG), postoperative myasthenic crisis (POMC) is the major complication related to thymectomy and has a strongly life-threatening effect. As a biomarker, whether the bilirubin level is a risk factor for MG progression remains unclear. This study aimed to investigate the association between the preoperative bilirubin level and postoperative myasthenic crisis (POMC).
UNASSIGNED: We analyzed 375 patients with MG who underwent thymectomy at Tangdu Hospital between January 2012 and September 2021. The primary outcome measurement was POMC. The association between POMC and bilirubin level was analyzed by restricted cubic spline (RCS). Indirect bilirubin (IBIL) was divided into two subgroups based on the normal upper limit of IBIL, 14 μmol/L.
UNASSIGNED: Compared with non-POMC group, IBIL levels were significantly higher in patients with POMC. Elevated IBIL levels were closely associated with an increased risk of POMC (p for trend = 0.002). There was a dose-response curve relationship between IBIL levels and POMC incidence (p for non-linearity = 0.93). However, DBIL levels showed a U-shaped association with POMC incidence. High IBIL level (≥14 μmol/L) was an independent predictive factor for POMC [odds ratio = 3.47, 95% confidence interval (CI): 1.56-7.8, p = 0.002]. The addition of high IBIL levels improved the prediction model performance (net reclassification index = 0.186, 95% CI: 0.039-0.334; integrated discrimination improvement = 0.0345, 95% CI: 0.005-0.065).
UNASSIGNED: High preoperative IBIL levels, especially those exceeding the normal upper limit, could independently predict the incidence of POMC.

The objective of this study is to characterize postoperative myasthenic crisis (POMC), after extended thymectomy and discuss the treatment options for this condition.
Clinical data from patients with generalized myasthenia gravis (MG) who underwent extended thymectomy at Xuanwu Hospital of the Capital Medical University from 2016 to 2018 were reviewed retrospectively. Patients were divided into two groups-POMC and non-POMC. Variables that could potentially predict POMC were analyzed. In the POMC group, the aforementioned variables were compared between patients with and without pneumonia.
Ninety-seven patients were enrolled. Thirty-eight (39.2%) patients developed POMC. The mean duration of mechanical ventilation (MV), length of intensive care unit stay, and duration of hospital stay were significantly longer in the POMC group (P < 0.001). Multivariate logistic regression analysis showed that disease severity, symptom duration longer than 12 mo, and transsternal thymectomy were independent risk factors for POMC. Postoperative pneumonia significantly prolonged the MV period (P = 0.012) and weaning from MV after intravenous immunoglobin (IVIg) treatment (P = 0.005) in POMC patients. Twenty-four (24.7%) POMC patients who received IVIg were successfully weaned from MV and were discharged.
Disease severity, symptom duration longer than 12 mo, and transsternal thymectomy were independent risk factors for POMC. Postoperative pneumonia worsens the prognosis of POMC.

OBJECTIVE: Postoperative myasthenic crisis (POMC) is one of the serious complications after extended thymectomy for patients with myasthenia gravis (MG). This study aims to clarify the risk factors of POMC occurrence.
METHODS: The clinical data of 55 MG patients (25 male, 30 female; median age, 51 years) who underwent extended thymectomy at Kyoto University from 2000 to 2013 were retrospectively reviewed. Surgical outcomes and pre- and perioperative predictive factors of POMC were analysed.
RESULTS: The preoperative Myasthenia Gravis Foundation of America stage was I, II, III and IV in 24, 22, 8 and 1 patients, respectively. Ten patients (18.2%) developed POMC; 6 required prolonged intubation over 24 h and 4 required reventilatory support. All patients were weaned after 5.6 (2-26) days of ventilator support, and were discharged. Univariate analysis revealed a correlation with a high preoperative anti-acetylcholine receptor antibody titre (P = 0.009), history of myasthenic crisis (MC) (P = 0.0004) and unstable MG after preoperative medical therapy (P = 0.003). Multivariate logistic regression analysis showed history of MC (odds ratio, 11.84; 95% confidential interval, 1.05-372; P = 0.045) and unstable MG (odds ratio, 29.45; 95% confidential interval, 2.00-1063; P = 0.013) independently predicted POMC. The surgical response rate was not significantly different between the two groups (66.7% with POMC, 85.4% without POMC; P = 0.334).
CONCLUSIONS: POMC occurred more frequently in unstable MG before surgery or in patients with a history of MC. Adequate preoperative medical therapy and perioperative care should be provided to these patients.