Intramuscular hematoma in rhabdomyolysis patients treated with low-molecular-weight heparin: Report of two cases

BACKGROUND: Rhabdomyolysis is a serious complication of heat stroke. Unlike that in acute kidney injury, the risk of muscle bleeding in rhabdomyolysis is often ignored and can substantially increase via the widespread use of anticoagulants, leading to the formation of intramuscular hematoma. CASE SUMMARY: During the summer, a middle-aged man and an elderly man were diagnosed with heat stroke, rhabdomyolysis, and acute renal impairment. Low-dose enoxaparin sodium was initiated for prophylaxis of deep vein thrombosis after the disease was stabilized with continuous renal replacement therapy. After that, the patients' hemoglobin decreased progressively, and no obvious intracranial, thoracic, digestive, or skin bleeding tendency was found. However, one of the patients had hip muscle pain, and computed tomography and color ultrasound confirmed that the patients separately had lumbar back and hip intermuscular hematoma. After discontinuation of anticoagulant drugs and monitoring of the steady increase in hemoglobin, the intermuscular hematomas were gradually absorbed. Following the use of prophylactic anticoagulation therapy, the patients' hemoglobin showed a progressive downward trend. Hematoma formation in the lumbosacral and buttock muscles was confirmed after excluding bleeding in typical regions (such as the digestive tract, thoracic cavity, and abdominal cavity). Anticoagulant drugs were discontinued immediately, and nutritional support was increased. Subsequently, the hemoglobin levels gradually increased, and the hematoma volumes gradually decreased. CONCLUSION: Patients with rhabdomyolysis have a risk of muscle bleeding, and inappropriate use of anticoagulants may lead to an increased risk or even to the formation of an intermuscular hematoma. When continuous blood loss is found in the body, the possibility of bleeding in the muscles and more typical sites should be considered.