**Question:** An 18-month-old boy slipped and hurt his right knee while walking. He presents with a tender, swollen, warm knee with significant hemarthrosis. His PT is 12 (normal, 13 seconds), PTT is over 100 (normal, 25 seconds), platelet count is 300,000/mm3, and bleeding time is normal. Initial management should consist of which of the following?

A. Conservative management (rest, ice, compression, elevation)
B. Blood transfusion
C. Platelet transfusion
D. Factor VIII concentrates

**Correct Answer:**

**Core Concept:** Hemarthrosis (bleeding into a joint) in children is usually due to coagulation defects or platelet dysfunction.

**Why the Correct Answer is Right:** In this case, the child has a prolonged PTT (partly normal PT) and normal platelet count and bleeding time. These findings suggest a hemostatic defect, specifically a deficiency in factor VIII, which is a coagulation factor involved in the intrinsic pathway of blood coagulation. Therefore, the correct management is to administer Factor VIII concentrates to correct the coagulation defect and prevent further bleeding.

**Why Each Wrong Option is Incorrect:**

A. Conservative management (rest, ice, compression, elevation) would be suitable for treating joint swelling and pain but does not address the underlying coagulation defect causing hemarthrosis.

B. Blood transfusion is irrelevant as the child has normal platelet count and bleeding time.

C. Platelet transfusion is not the correct treatment for hemarthrosis due to factor VIII deficiency. Increasing platelet count will not address the intrinsic pathway defect causing bleeding.

**Clinical Pearl:** A prolonged PTT and normal PT with normal bleeding time and platelet count should prompt the suspicion of a hemostatic defect, particularly factor VIII deficiency. Appropriate management involves administering Factor VIII concentrates to correct the coagulation defect and prevent further joint bleeding.