Trophoblastic pulmonary embolism.

Trophoblastic embolism is subclinical in normal pregnancy, pronounced in eclampsia, and massive in hydatidiform mole. Self-limited acute respiratory distress arises in 3% to 10% of molar pregnancies at the time of uterine evacuation. Infrequently death occurs; the principal findings are trophoblastic emboli in the pulmonary arterioles, edema of the lungs, and dilatation of the right side of the heart. Hyperthyroidism may develop, and fibrin may line the alveolar walls. Pathogenetic mechanisms include heart failure, hyperthyroidism, dilutional anemia, and pulmonary arteriolar blockage. Infusions of fluid and whole blood tend to cause pulmonary overload, which may precipitate right-sided heart failure. Preferred therapy consists of diuresis and ventilatory support, especially with oxygen under positive end-expiratory pressure.