Neuromuscular disease, respiratory failure and cor pulmonale

Respiratory muscle weakness is an uncommon cause of chronic respiratory failure and a rare cause of cor pulmonale. The problem may not be apparent unless specific physical signs are sought or appropriate investigations performed. We present three patients who presented diagnostic difficulty for prolonged periods until the presence of respiratory muscle weakness was considered. Once the diagnosis was established treatment with nocturnal nasal intermittent positive pressure ventilation produced a dramatic improvement in symptoms and allowed a return to a near normal lifestyle.