Unsuspected pulmonary emboli in well persons: the incomplete pulmonary infarction syndrome.

Pulmonary embolization from occult venous thrombosis in the lower extremities occurs in previously well individuals of all ages. Incomplete or hemorrhagic pulmonary infarction may result. The incomplete pulmonary infarction syndrome (IPIS) is characterized by sudden onset of pain in the lower chest, knife-like and stabbing in quality and accentuated by breathing, with pathognomonic abnormalities on chest x-rays. The physician should hospitalize the patient, begin heparinization and confirm the diagnosis with daily chest x-rays in multiple views. Failure to promptly diagnose and treat IPIS may lead to catastrophic, massive pulmonary embolism and death, or to recurrent embolism with pulmonary hypertension and chronic cor pulmonale, resulting in incapacitating dyspnea on exertion, and disability.