OBJECTIVE: The aim of this study was to identify the participation of the coagulation system in the differential diagnosis of pleural effusions. INTRODUCTION: Imbalance between immunologic and metabolic factors triggers a sequence of events resulting in pleural reactions and accumulation of fluid. The coagulation system, which is fundamental for the maintenance of homeostasis, contributes to the inflammatory process responsible for pleural effusions, and participates in cellular proliferation and migration as well as in the synthesis of inflammatory mediators. METHODS: We evaluated the laboratory profile of coagulation and fibrinolysis in 54 pleural fluids (15 transudates and 39 exudates). RESULTS: The coagulation system acts according to the pathophysiologic mechanisms involved in the development of pleural effusions. In inflammatory effusions (exudates), there is activation of coagulation with increased levels of fragment 1+2 and thrombin-antithrombin complex in addition to reduction of fibrinogen levels due to fibrinolysis and fibrin tissue incorporation. As a consequence, there is activation of the fibrinolytic system with increased levels of fibrin degradation products, including the D-dimer. These changes are not sufficient for differentiation of different subgroups of exudates. In transudates, these events were observed to a lesser degree. CONCLUSION: The coagulation system plays an important role in the development of pleural diseases. Coagulation tests show differences between transudates and exudates but not among exudate subgroups. Understanding the physiopathological mechanisms of pleural disorders may help to define new diagnostic and therapeutic approaches.

O quilotórax, normalmente secundário a doenças malignas, trauma, doenças congênitas, infecções e trombose da veia cava superior, é uma causa pouco freqüente de derrame pleural. O diagnóstico e tratamento precoces são importantes no sentido de prevenir a mais temida conseqüência do quilotórax, a má nutrição e conseqüente comprometimento do estado imunológico.

Chylothorax, an uncommon cause of pleural effusion, is usually secondary to malignancy, trauma, congenital diseases, infections and superior vena cava thrombosis. The early diagnosis and treatment are important to prevent the most fearful consequence of chylothorax, the malnutrition with a compromised immunological status.

O edema pulmonar de reexpansão é uma entidade rara, mas de notável mortalidade. Sua fisiopatologia ainda não é bem esclarecida, porém envolve fatores conhecidos, como a diminuição do surfactante pulmonar, e outros ainda incertos, como o papel dos mediadores inflamatórios na gênese e manutenção do processo. É imperativo o diagnóstico precoce, uma vez que o desfecho depende da agilidade no reconhecimento e tratamento dessa entidade. Tendo em vista a alta mortalidade, as medidas de prevenção ainda são a melhor estratégia no manuseio dos pacientes com doenças que podem levar ao edema pulmonar de reexpansão. Esta revisão discute os principais aspectos relacionados à fisiopatologia, diagnóstico, tratamento e prevenção do edema pulmonar de reexpansão, com recomendações práticas para o reconhecimento e adequada abordagem dessa entidade.

Reexpansion pulmonary edema (RPE) is a rare, but frequently lethal, clinical condition. The precise pathophysiologic abnormalities associated with this disorder are still unknown, though decreased pulmonary surfactant levels and a pro-inflammatory status are putative mechanisms. Early diagnosis is crucial, since prognosis depends on early recognition and prompt treatment. Considering the high mortality rates related to RPE, preventive measures are still the best available strategy for patient handling. This review provides a brief overview of the pathophysiology, diagnosis, treatment, and prevention of RPE, with practical recommendations for adequate intervention.