Reports on the treatment of bleeding associated with emicizumab administration are scarce. Herein, we report the case of an eight-year-old boy with moderate hemophilia A with an inhibitor who experienced tonsillar hemorrhage while undergoing emicizumab treatment. He visited our hospital for postprandial bloody vomiting. The activated partial thromboplastin time was 20.8 s; only a small amount of hemorrhage was observed in the retropharyngeal space, and tranexamic acid was administered. He experienced hematemesis on Day 2 of hospitalization, and fiberoptic laryngoscopy confirmed hemorrhage from the posterior tonsil. Varicose vessels were observed at the soft palate, and considering thrombosis, an emergency cauterization was performed instead of bypass therapy. In small children, observing the tonsils is difficult, and the coagulation ability of the patient with hemophilia A is inferior to that of healthy people, even under emicizumab administration. Thus, active hemorrhage assessment and appropriate hemostatic control are necessary.
Keywords: activated partial thromboplastin time; emicizumab; hemophilia A; hemostasis; tonsil.