Group Provides Best Practices for Preventing Myasthenic Crisis Following Thymectomy

Researchers of a new study are providing a comprehensive look at best practices for preventing myasthenic crisis (MC) following the removal of the thymus gland in patients with myasthenia gravis (MG). The recommendations, published in Gland Surgery, also provide guidance for addressing MC, should it occur.¹

MC, characterized by sudden exacerbation of muscle weakness, leading to respiratory failure requiring intubation and ventilation,² has been estimated to occur in up to 30% of patients after thymectomy.¹

“Summarizing the best evidence for the prevention and management of postoperative MC is an urgent need to guide clinical work,” wrote the researchers. “This study systematically searched for domestic and foreign evidence on the prevention and management of postoperative MC and integrated it to ultimately form the best evidence to provide a reference and guidelines for the formulation and standardization of measures for the prevention and management of postoperative MC.”

Care from a multidisciplinary team was underscored in order to help identify the most appropriate disease management based on patient health status.| Image Credit: MIND AND I-stock.adobe.com

In addition to determining best practices for preventing MC, efforts have also focused on predicting risk of the complication. One group of researchers developed a nomogram to predict the risk of MC. Among over 400 patients, those considered high risk had an 8.7-fold risk of MC following thymectomy.³

To compile evidence on mitigating the risk of MC, the researchers of this new study drew on data from 12 articles comprising clinical guidelines, expert consensus articles, systematic reviews, and a randomized controlled trial.

Proper risk assessment prior to surgery was highlighted by the literature, with recommendations for intervening to address controllable factors and implementing preventive measures for uncontrollable factors. Risk factors cited throughout the literature included long-term use of glucocorticoids, a history of MC, and a preoperative acetylcholine receptor antibody level of 100 nmol/L or higher. Use of neuromuscular blocking agents is not recommended, but if required, should consist of rocuronium bromide or vecuronium bromide followed by reversal with sugammadex.

The impact of a multidisciplinary team, comprising stakeholders ranging from the surgeon to pathologists, was underscored in order to identify the most appropriate management of disease based on the patient’s health status.

To improve lung function and recovery post surgery, as well as reduce the risk of postoperative MC, respiratory muscle training should be practiced prior to surgery. Training can include abdominal breathing and lip breathing, chest physical therapy, and limb muscle strength training. Training the respiratory muscles is also suggested following surgery, with recommendations including the use of a breathing trainer, airway care, and glossopharyngeal breathing.

“The postoperative prevention strategy mainly focuses on early extubation, airway management, and respiratory secretion management,” wrote the researchers. “On the other hand, for patients who are deemed high risk for MC after surgery, delaying extubation appropriately after surgery can effectively reduce both incidence of MC and risk of early re-intubation; a gastric tube can be placed before surgery to facilitate perioperative administration of pyridostigmine. The patient’s respiratory and muscle strength status should be closely monitored, and a clinical physician should determine the risk before removing the tube.”

For patients who do develop MC, several measures should be implemented if expiratory failure occurs, including intubation and positive pressure ventilation. Assessment of sleep quality, leakage, and blood oxygen should continue. Treatment for MC should include intravenous injection of human immunoglobulin or plasma exchange.

References

1. Chen P, Bao F, Pompeo E, Zhang X, Xu T. Summary of the best evidence for the prevention and management of myasthenic crisis after thymectomy. Gland Surg. 2024;13(4):540-551. doi:10.21037/gs-24-90

2.Wendell L, Levine J. Myasthenic crisis. Neurohospitalist. 2011;1(1):16-22. doi:10.1177/1941875210382918

3. Ruan Z, Su Y, Tang Y, et al. Nomogram for predicting the risk of postoperative myasthenic crisis in patients with thymectomy. Ann Clin Transl Neurol.2023;10(4):644-655. doi:10.1002/acn3.51752