Review Question - QID 108441

The most likely diagnosis in this case is hemophilia (types A and B are clinically indistinguishable). Hemophilia treatment involves replacement of the missing coagulation factor. In hemophilia A, the missing factor is factor VIII. In hemophilia B, the missing factor is factor IX.

The history of bruising and bleeding suggests that this patient has a bleeding disorder, which is supported by the warm and swollen joint (hemarthrosis). Bleeding disorders can be divided into platelet disorders, coagulation cascade disorders, and mixed disorders. This patient's deep bleeding is characteristic of coagulation disorders (hemearthrosis/bruising), but does not have any superficial bleeding (such as petechiae) that would indicate a platelet activity disorder. The lack of platelet involvement is further supported by a normal bleeding time. An elevated PTT with a normal PT suggests an isolated defect in the intrinsic coagulation cascade. Early onset intrinsic coagulation deficiencies are often caused by hemophilia. The diagnosis of hemophilia is further supported by the patient's family history of an affected maternal uncle since these disorders are X-linked recessive. Distinguishing the type of hemophilia and evaluating for presence of autoantibodies cannot be established clinically, but may be further assessed with mixing studies to see whether prolonged PTT normalizes upon administration of coagulation factors.

Incorrect Answers:
Answer 2: IVIG can be used to treat idiopathic thrombocytopenic purpura by inhibiting autoimmune mediated destruction of platelets. The normal bleeding time as well as the lack of superficial (platelet type) bleeding excludes this diagnosis.

Answer 3: Platelet administration can be used in patients who are thrombocytopenic. The normal bleeding time as well as the lack of petechiae suggest that the level of platelets is normal in this patient.

Answer 4: Vitamin K can be provided in patients who are deficient in vitamin K or on warfarin. Warfarin inhibits factors X, IX, VII, and II, affecting both arms of the coagulation cascade to cause mixed PT/PTT prolongation, which is not seen in this case.

Answer 5: von Willibrand disease (vWD) can lead to deep bleeding and prolonged PTT by destabilizing factor VIII. However, unlike this case, vWD presents also with prolonged bleeding time and superficial bleeding since von Willebrand factor is needed for platelet adhesion.

Bullet Summary:
Bleeding disorders should be evaluated in the context of platelet disorders or coagulation disorders. Inherited coagulation factor deficiencies are called hemophilias and present with an isolated elevation in PTT without affecting PT or bleeding time. Prevent further bleeding episodes by providing factor replacement therapy.