A retroperitoneal bleed induced by enoxaparin therapy.

Retroperitoneal bleeding is one of the most serious, potentially lethal complications of anticoagulation therapy. Although well documented in fully heparinized and coumadinized patients, there are only few reports of life-threatening hemorrhages in low-molecular-weight heparin (LMWH)-treated patients. We present a case of almost fatal spontaneous retroperitoneal bleeding in a 71-year-old woman with pneumonia and acute coronary syndrome. After receiving combination therapy with Lovenox (enoxaparin), aspirin, and Plavix for 5 days, she developed acute hemorrhagic shock and possible intra-abdominal compartment syndrome. Urgent computed tomography scan of the abdomen and pelvis was performed and showed a left retroperitoneal hematoma. The patient's condition continued to deteriorate, which prompted emergent exploration. After evacuating 3 L of free blood from the peritoneal cavity, we managed to stabilize the patient. Our case of spontaneous retroperitoneal bleeding adds to the growing number of cases in which enoxaparin has been associated with severe bleeding. A high index of suspicion is necessary if the patient displays any of the signs and symptoms that suggest major hemorrhage. It appears that those at highest risk receive doses approaching 1 mg/kg subcutaneously every 12 hours, have renal impairment, are of advanced age, and receive concomitant medications that can affect hemostasis. On average, a retroperitoneal hematoma occurs within 5 days of therapy with enoxaparin. In high-risk patients, enoxaparin activity (anti-factor Xa) should be carefully monitored.