Hypoventilation, Primary Alveolar

Key Features

• A rare syndrome ("Ondine curse") of unknown cause

• Characterized by inadequate alveolar ventilation despite normal airways, lungs, chest wall, respiratory muscles, and neurologic function

• Patients are usually nonobese males in their 40s and 50s

Clinical Findings

• Lethargy, headache, and somnolence

• Dyspnea is not present

• Cyanosis

• Evidence of pulmonary hypertension and cor pulmonale

• Erythrocytosis may be present

Diagnosis

• Arterial blood gas values show hypoxemia and hypercapnia, which improve with voluntary hyperventilation

Treatment

• Ventilatory stimulants are not effective

• Mechanical augmentation of ventilation via phrenic nerve stimulation, rocking bed, or ventilators may be helpful

• Supplemental oxygen should be given, with the caveat that nocturnal oxygen be given only if a sleep study demonstrates that it is effective and safe