Retroperitoneal hematoma-an unexpected complication of anticoagulant therapy in COVID-19 patients

Introduction Coronavirus disease 2019 (COVID-19) is associated with high inflammatory response, hemostatic disturbances, and high thrombotic risk. Despite thromboprophylaxis, a high incidence of thromboembolic events has been reported with a consequent increase in anticoagulant therapy from standard to intermediate or even therapeutic doses. However, published evidence on the incidence and outcome of the hemorrhagic complications of applied therapy is still limited.Outlines of cases We present two female COVID-19 patients, treated with anticoagulant therapy who suffered from major spontaneous bleeding and retroperitoneal hematoma. The first, a 64-year-old pa-tient, treated with non-invasive ventilation protocol in the Intensive Care Unit due to respiratory failure received a therapeutic dose of anticoagulant therapy adjusted to the anti-Xa assay. The cumulative dose of nadroparin was 150 IU/kg body weight/day. The second, a 60-year-old patient with the moderate clinical presentation on low flow oxygen support was treated with therapeutic doses of anticoagulant therapy calculated according to the body weight. Emergency open surgery was performed due to massive bleeding. No active surgical bleeding was detected, and retroperitoneal hematomas were assumed to be complications of the applied anticoagulant therapy. Both patients were discharged and fully recovered.Conclusion Although rare, severe hemorrhage requires attention when considering anticoagulant therapy in COVID-19. Uncommon sites of spontaneous bleeding suggest additional evaluation on a case-by-case basis, given that a diagnosis is often delayed due to a lack of specific presenting symptoms. Further studies are needed to verify the risk-benefit ratio of different regiments of anticoagulant therapy in patients with COVID-19.