Navigating Anxiety Management in Myasthenia Gravis Crisis With Prolonged Corrected QT (QTc): A Case Report.

Myasthenia gravis (MG) crisis presents significant challenges in medication management, as treatment must balance risks of respiratory depression, worsening neuromuscular transmission, and QT interval prolongation when psychiatric symptoms such as anxiety coexist with medical instability. Concurrent corrected QT (QTc) prolongation further constrains treatment selection by limiting the use of many commonly prescribed anxiolytic and psychotropic agents. We present the case of a 75-year-old male with MG crisis and a markedly prolonged QTc interval of 563 ms, requiring careful balancing of neuromuscular, respiratory, and cardiac risks. Sertraline was selected due to its relatively favorable cardiac profile and established efficacy in anxiety disorders. The patient tolerated treatment without worsening of neuromuscular symptoms, and improvement in anxiety symptoms and QTc interval was observed during hospitalization. These changes occurred in a closely monitored, multifactorial clinical setting that included discontinuation of QT-prolonging medications and overall medical stabilization; therefore, the observed improvements should be interpreted as temporal associations rather than evidence of a direct causal effect of sertraline.