Mucous plug syndrome. A pulmonary embolism mimic

Reported are ten instances of major bronchial obstruction by mucous plugs in eight patients during which the clinical features resembled pulmonary embolism. Perfusion lung studies showed significantly diminished perfusion of the involved portions of the lungs. The chest radiographs generally did not, however, reflect the severity of the airway obstruction and in some instances were completely normal. The ventilation studies indicated the extent and severity of the obstruction and matched with the perfusion scans. Pulmonary arteriograms were performed in three patients and gave direct evidence of focally diminished lung perfusion without embolism. The physiologic mechanisms underlying the condition are discussed