What is the primary cause of mortality in patients with Duchenne muscular dystrophy?

The primary cause of mortality in patients with Duchenne muscular dystrophy (DMD) is indeed respiratory failure, which typically occurs due to progressive weakness of the respiratory muscles that leads to inadequate ventilation and impaired gas exchange. Patients with DMD experience degeneration of muscle fibers, including those involved in respiration, which means over time, they become increasingly unable to effectively breathe on their own.

As DMD progresses, the intercostal muscles and diaphragm weaken, resulting in hypoventilation, atelectasis, and ultimately respiratory failure. This condition may be exacerbated by scoliosis and other musculoskeletal deformities that further impair lung function. The onset of respiratory complications usually occurs in the teenage years or early adulthood, leading to increased reliance on assisted ventilation and, without intervention, significant morbidity or mortality.

While high-output cardiac failure can also occur in DMD due to cardiomyopathy, respiratory failure remains the most direct and common cause of death as patients age. Therefore, understanding the progression of respiratory muscle involvement is crucial in managing the health of individuals with DMD.