Aquired hemophilla a after covid-19 infection in an 5-week old infant

Abstract Clinical Summary: We report a case of a 5 week male with acquired Hemophilia A secondary to SARS-CoV-2 infection (COVID 19). He was born at 37 weeks gestation and was admitted to the NICU due to bilious emesis after birth and was found to have jejunal atresia for which he underwent surgical repair. He tolerated his surgery and NICU course for the first 5 weeks of life without any bleeding complications. He contracted COVID 19 infection at 3 weeks old. Two weeks later he developed prolonged bleeding from blood draws and “oozing” around vascular access sites. Hematology was consulted to assess the newly developed coagulopathy. Hemostasis evaluation was significant for elevated activated partial thromboplastin time (aPTT) of 99 seconds. Labs where repeated and demonstrated persistently elevated aPTT of 94 and 88 seconds. The subsequent mixing study was consistent with the presence of an inhibitor. One-stage factor assays for common inhibitor targets were performed. Factor VIII activity was <1% and Factor IX activity was within expected values for age at 64%. Bethesda titers for the inhibitor was 3 BU. Despite plasma administration, he continued to have bleeding. The patient was treated with a bypassing agent over immunosuppression given his age and COVID 19 infection. Emicizumab 3 mg/kg was initiated and his bleeding improved. He received a total of three doses of Emicizumab over a 3 week period, prior to surgical re-anastomosis and has had no additional bleeding concerns.Discussion: Acquired Hemophilia A is an immune-mediated condition in which inhibitors or neutralizing autoantibodies against factor VIII cause decreased activity and precipitate bleeding diaphysis. This can lead to severe bleeding complications, with high mortality and morbidity. Acquired Hemophilia A is very rare in children and rare in adults with estimated 0.2 -1 cases per million annually and mortality rate ranging from 8-22%. It is typically associated with underlying conditions including autoimmune disease, cancer or pregnancy. Acquired Hemophilia A has been described with COVID 19 infection and rarely with vaccination, but previous reported cases have all been in adults. Acquired Hemophilia A is typically treated with immunosuppressive therapy, usually high dose steroids in pediatric patients, in addition to bypassing agents which help with the bleeding complications. Emicizumab is a bispecific antibody that mimics the cofactor function of activated factor (F) VIII. It prevents bleeds in patients with congenital hemophilia A regardless of the inhibitor status. It has been showed to be effective in preventing bleeding in patient with acquired hemophilia A.Conclusion:We report a case of acquired Hemophilia A in a very young infant following COVID 19 infection that caused clinically significant bleeding and responded to Emicizumab without the need for immunosuppression. To our knowledge, this is the youngest patient with acquired Hemophilia A following COVID 19 reported in the literature. This case demonstrates that COVID 19 infection can potentially lead to autoantibody formation even in an infant with a very immature immune system. Thus, periodic assessments of coagulation studies should be considered in any patient with a recent history of COVID 19 and new or worsening bleeding concerns. Additionally, our case demonstrates that Emicizumab alone can be effective in the treatment of acquired Hemophilia A in a pediatric patient with contraindications to immunosuppression.