[Two cases of acute respiratory failure associated with pneumonia requiring mechanical ventilation before diagnosis of amyotrophic lateral sclerosis].

We present two cases of acute respiratory failure requiring mechanical ventilation before diagnosis of amyotrophic lateral sclerosis (ALS). The patients were men of 60 (patient 1) and 74-years old (patient 2), both of whom exhibited acute respiratory failure requiring mechanical ventilation. Diagnoses of ALS were made because of continuous aspiration caused by bulbar palsy in patient 1, and, in patient 2, because of the progressive muscle atrophy that occurred during unsuccessful attempts to wean the patient from ventilatory support. Physicians should be aware of the possibility of ALS in cases of acute respiratory failure, CO2 narcosis, continuous aspiration, and difficulty of weaning from mechanical ventilation.