[Exertional dyspnea as the initial manifestation of amyotrophic lateral sclerosis]

In amyotrophic lateral sclerosis (ALS), respiratory problems are usually late complications. However, ALS may occasionally present with exertional dyspnea as the primary symptom, as was the case in the patient reported here. On the basis of this case and the literature, the diagnostic and therapeutic aspects of the neurologic causes of dyspnea are discussed. Where there is a discrepancy between severity of blood gas alterations, changes in lung volume determinations and severity of dyspnea, a neuromuscular disorder must be considered in differential diagnosis.