Diaphragmatic crus thickness as a marker of dysfunction and predictor of myasthenic crisis after thymectomy in generalized myasthenia

Abstract

Myasthenia gravis (MG) is an autoimmune disorder characterized by impaired neuromuscular transmission. This can lead to respiratory failure in case of myasthenic crisis. While thymectomy is a recognized treatment, it carries a high risk of postoperative myasthenic crisis (POMC). An important factor is diaphragmatic dysfunction (DD) remaining poorly studied in myasthenic patients. Objective. To assess diaphragmatic crus thickness (DCT) using computed tomography in MG patients before thymectomy, its role as a subclinical marker of DD and predictor of POMC, as well as relationship with anthropometric, spirometry and echocardiography parameters. Material and methods. A retrospective study compared 6 generalized MG patients and 7 patients with thymoma and no MG. Results. We found significant DCT reduction in MG patients, primarily in the left crus. This thinning correlated with moderately impaired respiratory function. Intact echocardiography parameters indicated myogenic nature of respiratory insufficiency. Classification of clinical phenotypes of MG, incorporating these morphometric and functional data, was developed to reflect the risk of POMC. Conclusion. DCT measurement is a valuable diagnostic and prognostic tool for early identification of subclinical DD and risk stratification in MG patients. Integration of diaphragmatic morphometry into preoperative protocols may be valuable to personalize treatment and improve post-thymectomy outcomes. These findings require validation in larger prospective studies.