Abstract
In amyotrophic lateral sclerosis (ALS) with respiratory onset, no limb weakness at the time of ventilator dependency is rare. A 78-year-old man was transferred to our emergency department with sudden dyspnea and unconsciousness. He was ambulatory and was able to commute the day before. On arrival, his respiration was nearly arrested, with PaCO2 of 138 mmHg. He was intubated and mechanically ventilated. He regained consciousness, along with improvement of hypercapnia. Ultrasonographic study revealed almost complete paralysis of the bilateral diaphragm, and his differential diagnosis included neuromuscular disease. Nevertheless, he remained ambulatory in our ICU after tracheotomy on day 7, while being dependent on a ventilator. The patient insidiously presented limb muscle atrophy and increased deep tendon reflexes. Neurogenic change in needle electromyography led to a final diagnosis of ALS on day 36. While vital capacity remained approximately 600 ml, frequent recurrence of atelectasis due to decreased airway clearance made weaning difficult and resulted in ventilator dependency. The patient remained ambulatory at the time of ICU discharge on day 118. As diagnosis of ALS is often made during an ICU stay, intensivists should include ALS in differential diagnosis of patients with respiratory muscle paralysis, even without evident limb weakness.
