How can respiratory dysfunction develop in ALS?

In ALS, respiratory dysfunction can be caused by various factors. The most common factor is muscle weakness of the respiratory muscles (diaphragm, rib muscles, abdominal muscles), which leads to respiratory weakness (hypoventilation) and a reduction in coughing (coughing weakness). Hypoventilation results in an accumulation of carbon dioxide in the blood (“carbon dioxide retention”) and associated symptoms (sleep disturbance, daytime tiredness, respiratory effort).

In addition to weakness of the respiratory muscles, weakness of the tongue and pharyngeal muscles can be another factor in ALS-related respiratory dysfunction. It can be caused by a narrowing or obstruction of the upper airways (slackening or stiffness of the tongue and pharynx) or by an accumulation of saliva in the mouth, throat or pharynx (sialorrhea). There are various treatment options for respiratory dysfunction (non-invasive ventilation therapy, cough assistance, invasive ventilation).