Researchers from China identified independent risk factors for myasthenic crisis in patients with myasthenia gravis in a single-center study that they conducted in the Department of Thoracic Surgery of Beijing Hospital. They published their findings in the Journal of Cardiothoracic Surgery

A poor Osserman classification score, a previous history of myasthenic crisis, a higher dose of pyridostigmine before surgery, and higher American Society of Anesthesiologists (ASA) scores are associated with a higher risk of myasthenic crisis following surgery.

Read more about the complications of myasthenia gravis

The researchers concluded that patients with these characteristics “should be highly alert to the occurrence of postoperative myasthenic crisis.”

To assess the effect of different factors on the occurrence of myasthenic crisis in patients with myasthenia gravis, the team led by Hongfeng Tong retrospectively analyzed 387 patients with the disease who had extended thymoma resection for the treatment of their disease.

The researchers analyzed the patients’ Osserman classification, preoperative course, pyridostigmine dosage, the method used during surgery, the duration of surgery, and the amount of blood loss during surgery. They then analyzed the factors associated with the occurrence of myasthenic crisis after the surgery.

They identified Osserman classification 2B + 3 + 4, a previous history of myasthenic crisis, a pyridostigmine dosage of more than 240, and an ASA score of 2 or 3 as independent risk factors for myasthenic crisis.

“Therefore, non-thymoma [myasthenia gravis] patients should be highly vigilant if combined with the above conditions, take countermeasures in advance, and timely deal with the [myasthenic crisis] that may occur at any time to ensure the safety of patients,” they wrote.

Myasthenic crisis is a complication of myasthenia gravis that can be life-threatening. It is characterized by worsening of muscle weakness, which can result in respiratory failure. Patients who have a myasthenic crisis require intubation and mechanical ventilation.


Jiao P, Wu F, Liu Y, et al. Analysis of influencing factors of perioperative myasthenic crisis in 387 myasthenia gravis patients without thymoma in a single center. J Cardiothorac Surg. Published online January 12, 2023. doi:10.1186/s13019-023-02136-1