Acquired hemophilia A and deep vein thrombosis attributable to the Pfizer-BioNTech SARS-CoV-2 mRNA vaccine—case report

Background: Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder that occurs in a sporadic, nonhereditary pattern. It is caused by circulating autoantibodies against clotting factor VIII that are triggered by several conditions. Moreover, AHA is clinically distinct from the inherited form of hemophilia A, with a different natural history and management approach, necessitating a high-index of suspicion in at-risk patients. Coronavirus disease 2019 (COVID-19) has emerged as a multisystemic disease whose manifestations are continuously being evaluated. There are few case reports of AHA associated with COVID-19 infection, while one case of AHA has been associated with COVID-19 vaccination. Similarly, deep venous thrombosis (DVT) frequently complicates COVID-19 infection, but two cases of DVT have been reported following COVID-19 vaccination. We report the occurrence of both AHA and DVT in a 63-year-old male patient within one week of receiving his first dose of the Pfizer-BioNTech SARS-CoV-2 mRNA vaccine. Case Discussion: Patient is a 63-year-old male who presented with a 3-day history of left lower extremity (LLE) swelling and pain. He was hemodynamically stable, but examination showed exquisite tenderness, ecchymosis, and pitting edema at the calf of the LLE. He had normal platelet counts at presentation but had mild anemia (11.9 g/dL) and elevated activated partial thromboplastin time (APTT) of 68.0 seconds. Venous Doppler ultrasound showed acute DVT in the left popliteal vein, necessitating commencement on heparin drip. He developed progressively worsening hematomas, symptomatic anemia that required red cell transfusions, and persistently elevated APTT despite stopping the heparin drip. Work up for pulmonary embolism, malignancy, and disseminated intravascular coagulopathy (DIC) were negative. Antiphospholipid antibodies and lupus anticoagulant were also negative. He had low factor VIII levels, tested positive for factor VIII inhibitor, and PTT mixing studies were consistent with acquired factor inhibitor. Treatment involved administration of Factor Eight Inhibitor Bypassing Activity (FEIBA) as well as intravenous methylprednisolone and cyclophosphamide. Following resolution of active bleeding with evidence of stable hemoglobin concentration, he was discharged home on oral prednisone and cyclophosphamide. Conclusions: This case report highlights the possibility of AHA and DVT as rare, potentially lifethreatening adverse events that could occur following COVID-19 vaccination, which is currently the most effective tool employed in controlling the COVID-19 pandemic.