A 12-year-old boy experiences excessive bleeding following a tooth extraction. His past medical history includes episodes of painful joint swelling from minor trauma. Physical examination shows a soft and nontender abdomen with a liver span of 10 cm. The spleen is not palpable. Laboratory results are as follows: This patient most likely has a deficiency involving which of the following factors?

Question

A 12-year-old boy experiences excessive bleeding following a tooth extraction.  His past medical history includes episodes of painful joint swelling from minor trauma.  Physical examination shows a soft and nontender abdomen with a liver span of 10 cm.  The spleen is not palpable.  Laboratory results are as follows:  This patient most likely has a deficiency involving which of the following factors?

Quizplus · Accepted Answer

11ec160b_3af0_becd_9249_719baa655f2a_MD0001_00 This patient's hemarthroses and excessive bleeding following tooth extraction are suggestive of a coagulopathy (ie, clotting factor deficiency). Coagulopathies generally present with deep-tissue bleeding into joints, muscles, and subcutaneous tissue. In contrast, platelet defects typically manifest with mucocutaneous bleeding (eg, epistaxis, petechiae). The patient's laboratory results show a normal bleeding time, normal activated partial thromboplastin time (aPTT), and a prolonged prothrombin time (PT). The normal bleeding time indicates adequate platelet function, and the normal aPTT indicates an intact intrinsic coagulation system. However, the prolonged PT indicates a defect in the extrinsic coagulation pathway. Therefore, the patient is most likely deficient in factor VII. (Choice B) Factor VIII deficiency results in classic X-linked hemophilia A. Coagulation studies will show a normal bleeding time, normal PT, and prolonged aPTT. (Choice C) Factor XI deficiency results in a rare autosomal recessive disorder called hemophilia C. Spontaneous bleeding is rare in this condition, but affected patients are at increased risk for bleeding following surgery or trauma. Coagulation studies will show a prolonged aPTT and normal PT. (Choice D) Hageman factor (factor XII) deficiency is an autosomal recessive disorder that does not typically cause clinically significant bleeding despite aPTT prolongation. (Choice E) von Willebrand factor (vWF) functions as both a carrier molecule for factor VIII (protecting it from being degraded) and as a mediator of platelet adhesion to the endothelium. It presents with prolonged bleeding time and normal/prolonged aPTT. Educational objective: A normal bleeding time indicates adequate platelet hemostatic function. A normal activated partial thromboplastin time (aPTT) indicates an intact intrinsic coagulation system. Prolonged prothrombin time in the setting of normal aPTT indicates a defect in the extrinsic coagulation system at a step that is not shared with the intrinsic system.

A 12-Year-Old Boy Experiences Excessive Bleeding Following a Tooth Extraction