title: Characteristics of pleural effusions associated with pulmonary embolism.
abstract: Pleural fluid characteristics were analyzed in 26 patients with pulmonary embolism. All determinations were highly variable. A bloody effusion occurred in 65%, while clear fluid was found in 35%. White blood cell counts had a wide distribution of values; polymorphonuclear leukocytes predominated in 61% and lymphocytes in 39%. Less than two thirds of tested specimens were exudates by standard criteria. Only 27% of effusions had the "typical" pattern of bloody appearance, polymorphonuclear predominance, and characteristics of an exudate. Roentgenographically evident infiltrates occurred in 62% and were correlated with bloody pleural fluid (P less than .01), which suggests that infarction is not necessary for effusion to occur, but may account for a bloody appearance. The variability of these results indicates that there are no typical or diagnostic pleural fluid findings in pulmonary embolism.
mesh_terms: D001772:Blood Cell Count; D004912:Erythrocytes; D006801:Humans; D008214:Lymphocytes; D009504:Neutrophils; D010996:Pleural Effusion / Q000166:cytology* / Q000209:etiology; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography