A 15-year-old boy is admitted to the hospital for management of right elbow pain and swelling. The symptoms began 5 days ago while he was watching television at home. The patient has factor VIII deficiency and has been receiving prophylactic recombinant factor VIII infusions through a subcutaneous port 3 times weekly since he was 11 months old. When this episode began, the frequency of his infusions was increased to daily, but the swelling and pain remain. Temperature is 37.6 C (99.7 F). The right elbow has edema, is tender to palpation, and has limited range of motion relative to the left elbow. Laboratory results are as follows: Which of the following is the most likely cause of this patient's symptoms?

Question

A 15-year-old boy is admitted to the hospital for management of right elbow pain and swelling.  The symptoms began 5 days ago while he was watching television at home.  The patient has factor VIII deficiency and has been receiving prophylactic recombinant factor VIII infusions through a subcutaneous port 3 times weekly since he was 11 months old.  When this episode began, the frequency of his infusions was increased to daily, but the swelling and pain remain.  Temperature is 37.6 C (99.7 F).  The right elbow has edema, is tender to palpation, and has limited range of motion relative to the left elbow.  Laboratory results are as follows:  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d6a0_5018_bc81_f976f70274a8_MD0003_00 Factor VIII deficiency (hemophilia A) is an X-linked recessive bleeding disorder associated with recurrent hemarthrosis (bleeding into joints), as seen in this patient. Treatment is factor VIII replacement therapy (eg, recombinant factor VIII infusions through a port). However, inhibitor development occurs in approximately 25% of patients with severe hemophilia A (ie, frequent, spontaneous bleeds) as a complication of treatment. The immune system recognizes the infused factor as foreign, forming antibodies that interfere with factor function. Therefore, an inhibitor should be suspected when a patient with hemophilia A on factor replacement therapy develops increased bleeding frequency or has hemorrhage refractory to treatment. In addition, because factor VIII belongs to the intrinsic coagulation pathway, prolonged PTT, but normal PT, occurs if factor VIII is inhibited. Regular screening for inhibitor development is performed when patients with severe hemophilia receive factor infusions as well as when an inhibitor is clinically suspected. Treatment of an acute bleed in a patient with inhibitor development often involves bypassing products (eg, recombinant activated factor VII, activated prothrombin complex concentrates); such agents work downstream in the coagulation cascade to promote clotting without the need for factor VIII. (Choices A and E) Acquired von Willebrand disease and disorders of platelet function present with bruising and mucosal bleeding rather than with hemarthrosis. (Choice B) Fibrinogen (factor I) is in the common final coagulation pathway, and dysfunction causes prolonged PT and PTT. This patient's PT is normal. (Choice C) Heparin-induced thrombocytopenia is due to an autoantibody against heparin and typically presents with thrombosis and decreased platelet count, which are not seen in this patient. Educational objective: Inhibitor development occurs in 25% of patients with severe factor VIII deficiency. It should be considered in a patient with bleeding refractory to replacement therapy or with increased bleeding frequency. References: A close insight to factor VIII inhibitor in the congenital hemophilia A. (http://www.ncbi.nlm.nih.gov/pubmed/27367203)

A 15-Year-Old Boy Is Admitted to the Hospital for Management