Abstract
Warfarin therapy provides extensive antithrombotic benefits and, thus, is widely used in the general population. However, as with most medications, there are also risks associated with warfarin use. Specifically, because of the narrow therapeutic window of this drug, patients taking it are at a much higher risk of accidental bleeding. Additionally, patients may also present with bleeding complications when infected with illnesses with coughing as a symptom, such as influenza or COVID-19. These patients have the potential to suffer hemorrhagic morbidities related to the increased intra-abdominal and intra-thoracic pressures that are generated from coughing. Moreover, a synergistic effect is seen when patients find themselves in a situation where they are taking anticoagulation therapy and become infected with illnesses such as influenza or COVID-19. We present a case in which an individual on warfarin therapy was infected with Influenza A. This combination of factors eventually led to massive hemorrhage and large abdominal wall hematoma formation. This case brings to light the importance of having a low threshold for considering the prospect of massive hemorrhage in any patient who is anticoagulated and develops a condition that is associated with increased abdominal pressure. Because these bleeding events can have devastating effects, raising awareness of this risk is increasingly important. Early detection of massive hemorrhage will lead to better outcomes and can ultimately be life-saving for these patients.