Hemothorax due to warfarin overdose

Resumo

The vitamin K antagonists are the most widely used oral anticoagulant. Although bleedings are common side effect, development of hemothorax is rare. Most cases are associated with impairment in pleura or parenchyma structural alteration in the presence of INR values outside therapeutic range. We report the case of a patient with rheumatoid arthritis presenting with massive hemothorax under anticoagulation with warfarin and present an overview of the main aspects related to warfarin overdose.A 58-year-old woman was evaluated due to transvaginal bleeding and dry cough. In her past medical history, rheumatoid arthritis, smoking and deep venous thrombosis was reported. She had clinical signs of anemia and pulmonary auscultation revealed no lung sounds in the lower third of the right hemithorax. The hemoglobin was 7,2g/dL and the international normalized ratio (INR) was greater than 9. The tomographic study showed pleural effusion and pulmonary embolism in the left pulmonary artery with chronic characteristics, but was negative for pulmonary infarct. The patient received crystalloids, vitamin K and transfusions of blood products. Thoracentesis demonstrated presence of hemothorax. After recovery and hospital discharge, an elective pleural biopsy reveals pleural tissue without histological changes and no signs of malignancy. Despite the fact that hemothorax is a rare complication in patients on oral anticoagulants, this occurrence can be life threatening. The evidence of pleural effusion in these patients should always raise the suspicion of hemothorax. Comorbidities that may affect the lung may be predisposing factors for the occurrence of hemothorax, but the roll of pleural and parenchymal diseases of the lung is not fully clarified and investigation of such conditions should be encouraged.