case report

Abstract Rationale: Spontaneous retroperitoneal hematomas due to anticoagulant therapy rarely occur. Retroperitoneal hematomas can cause severe pain in the groin, quadriceps femoris muscle weakness, hemodynamic instability, and abdominal distension. They rarely cause compressive neuropathy of the femoral nerve transversing the iliacus muscle. Differential diagnosis is not easy because they have similar clinical features to retroperitoneal hematomas. Patient concerns: A 72-year-old female patient whose right arm was stuck in a bookshelf for 5 days developed right cephalic vein thrombosis. After 5 days of intravenous heparin therapy for venous thrombosis, she presented with sudden right groin pain, right leg paresis, hemodynamic instability, and abdominal distension. Diagnosis: Emergency abdominal and pelvic CT showed a large number of hematomas in the bilateral retroperitoneal space with active bleeding of the right lumbar artery. An electrodiagnostic study was performed 2 weeks later to check for neuromuscular damage in the right lower extremity, and right compressive femoral neuropathy was confirmed. Interventions: Heparin therapy was discontinued; emergency embolization of the lumbar artery was performed. After 2 weeks, the patient started receiving physical, occupational, and transcutaneous electrical stimulation therapies. Outcomes: She became hemodynamically stable after arterial embolization; a significant decrease in hematoma and patency of the femoral nerve was confirmed on follow-up pelvic MRI. After 2 months of comprehensive rehabilitation, the muscle strength of the right leg significantly improved, and the pain disappeared. Lessons: Although rare, spontaneous retroperitoneal hematomas may occur in patients receiving anticoagulant medications. They may even occur in patients receiving emergency anticoagulant therapy. Compressive femoral neuropathy due to retroperitoneal hematomas should be considered if muscle weakness and groin pain are observed. Early diagnosis and appropriate treatment plan of compressive femoral neuropathy due to retroperitoneal hematoma are helpful for a good prognosis.