Pulmonary Hemorrhage - Etiology and Pathogenesis

Etiology and Pathogenesis

Infant prematurity is the factor most commonly associated with Pulmonary Hemorrhage. Other associated factors are those that predispose to perinatal asphyxia or bleeding disorders, including toxemia of pregnancy, maternal cocaine use, erythroblastosis fetalis, breech delivery, hypothermia, infection, Infant respiratory distress syndrome (IRDS), administration of exogenous surfactants (in some studies) and Extracorporeal membrane oxygenation (ECMO).

Although the pathogenesis is uncertain, it is probable that the symptoms are a consequence of hemorrhagic pulmonary edema, as the hematocrit is lower than normal blood (usually 15-20% less) and the concentration of small proteins is higher than in plasma. It is postulated that the infant suffers from asphyxia with resultant heart attack; this increases pulmonary microvascular pressure, resulting in pulmonary edema. Contributing factors include factors that favor increased filtration of fluid from pulmonary capillaries (e.g., low concentration of plasma proteins, high alveolar surface tension, lung damage, hypervolemia).