APCU25CR10 Spontaneous retroperitoneal hemorrhage during anticoagulation for pulmonary embolism: a concealed catastrophe

Introduction Spontaneous retroperitoneal hemorrhage (SRH) is a rare but life-threatening complication, most often associated with anticoagulant or antiplatelet therapy. It occurs in the absence of trauma or invasive procedures, and delayed recognition can be fatal.Case Presentation A 76-year-old former heavy smoker with diabetes mellitus, hypertension, benign prostatic hyperplasia, bilateral blindness and chronic lung disease was recently diagnosed with pulmonary embolism. Computed tomography pulmonary angiography (CTPA) revealed a central filling defect in the posterior segment of the right lower lobe, with features of pulmonary edema on a background of emphysema and bullous disease. His simplified pulmonary embolism severity index score was 2, indicating intermediate risk. He was initially anticoagulated with oral dabigatran 150 mg twice daily. He was later readmitted with hypercapnic respiratory failure, during which his anticoagulation was switched to therapeutic dose of subcutaneous fondaparinux. During the course of admission, he developed acute abdominal pain with right flank ecchymosis and a haemoglobin drop from 12 g/dL to 6 g/dL. CT abdomen revealed a large retroperitoneal hematoma in the right lumbar region, measuring 9.6 × 9.9 × 13.3 cm, with contrast blush within the iliacus muscle. Mass effect was observed, compressing the right common and external iliac veins, along with a filling defect in the right common iliac vein consistent with thrombosis. Given his comorbidities and poor prognosis, surgical intervention was not pursued. He was managed conservatively with blood transfusion, analgesia, and oxygen supplementation. Anticoagulation was discontinued after a risk–benefit discussion. The patient stabilized with supportive measures and was discharged home.Discussion Retroperitoneal hemorrhage is often underrecognized until patients develop hemodynamic compromise, as its presentation may be subtle and nonspecific. Anticoagulation, particularly with heparin, remains a major risk factor. In the absence of standardized management guidelines, decisions must be individualized, ranging from supportive care to urgent intervention. Early imaging and heightened vigilance in patients on anticoagulation are critical, as timely recognition can prevent progression of shock and organ compression.Conclusion Retroperitoneal hemorrhage should be considered in any anticoagulated patient presenting with unexplained anaemia, flank pain, or hypovolemia. Early detection and proactive management may reduce morbidity by limiting hematoma expansion and tissue compression.