Retroperitoneal Hematoma and Enoxaparin

TO THE EDITOR: Spontaneous retroperitoneal hematoma associated with the use of enoxaparin is not widely reported. A MEDLINE search of the literature from 1966 to April 1999 revealed no cases associated with the current recommended therapeutic dose of 1 mg/kg of body weight every 12 hours (1). We describe a patient who developed a fatal hematoma after use of enoxaparin for acute deep venous thrombosis. A 69-year-old man was transferred to our facility for management of a urinary tract infection. His medical history included ischemic cardiomyopathy, chronic renal insufficiency, localized prostate cancer, and chronic anemia. He had no history of coagulopathy, renal tumors, liver disease, or abdominal aortic aneurysm. He took no antiplatelet agents or anticoagulant agents. No adverse drug reactions were reported. He had no family history of coagulopathy and reported no long-term alcohol use. The initial physical examination revealed no peritoneal signs, abdominal bruising, or scrotal hematoma. Laboratory data showed a hemoglobin level of 9.3 g/dL, a normal platelet count, and a creatinine concentration of 300.6 mol/L (3.4 mg/dL). Vancomycin and piperacillin-tazobactam therapies were continued for the infection. Aspirin treatment was started for a complicating non-Q-wave myocardial infarction. The patient developed acute deep venous thrombosis of the right common femoral vein, which was diagnosed by lower-extremity Doppler examination. The patient began receiving 80 mg of enoxaparin subcutaneously every 12 hours. Four days later, he became hypotensive. Abdominal examination revealed new periumbilical bruising, and the patient's hemoglobin level decreased to 6.9 g/dL. Abdominal computed tomography (Figure on page 796) showed a left retroperitoneal hematoma measuring 7.5 15 cm. No aortic aneurysm was noted. The patient died despite supportive care. Figure. Computed tomographic scan of the abdomen. Enoxaparin has advantages over unfractionated heparin (2, 3), but clinicians must be wary of potential complications. Reports of associated spinal hematoma have already been noted, and synergism between aspirin and enoxaparin has been described (3, 4). Finally, retroperitoneal hematoma has been reported with dalteparin, another type of low-molecular-weight heparin (5).