[Weak respiratory muscles as a first sign of ALS: symptoms may put the physician on the wrong track].

Background: Patients with decreased exercise tolerance and orthopnoea are often referred to an internist, a cardiologist or a pulmonologist. These symptoms can also be caused by weakness of the respiratory muscles, as an indication of a neuromuscular disease. If these symptoms are not recognized as such, this may result in a delay in timely diagnosis.