Use this case to answer the following questions:
A 5-year-old boy visits his primary care physician after an accident on his bike.It was his first accident, and he fell on his knees.His mother noticed severe swelling in his knees and elbows, but thought that it was from the accident.She placed an ice pack on the affected areas and put him to rest.After a few days, the swelling had not improved, so she made an appointment to see his pediatrician.The physician asks him a few questions about the accident and then proceeds to perform a physical examination.The physician notes small hematomas on his elbows and knees and also on his upper torso.He draws blood, and the results are shown below. PT: 12.2 sec (RR: 11.3-12.8 sec)
INR: 1.12
APTT: 72 sec (RR: 23-32 sec)
Platelet aggregation studies: normal aggregation with all agonists
The physician admits him to the area hospital.
-What should be his next course of action in investigating these results?

Question

Use this case to answer the following questions: 
A 5-year-old boy visits his primary care physician after an accident on his bike.It was his first accident, and he fell on his knees.His mother noticed severe swelling in his knees and elbows, but thought that it was from the accident.She placed an ice pack on the affected areas and put him to rest.After a few days, the swelling had not improved, so she made an appointment to see his pediatrician.The physician asks him a few questions about the accident and then proceeds to perform a physical examination.The physician notes small hematomas on his elbows and knees and also on his upper torso.He draws blood, and the results are shown below. PT: 12.2 sec (RR: 11.3-12.8 sec)
INR: 1.12
APTT: 72 sec (RR: 23-32 sec)
Platelet aggregation studies: normal aggregation with all agonists
The physician admits him to the area hospital.
-What should be his next course of action in investigating these results?

Quizplus · Accepted Answer

The prolongation of APTT suggests a possible deficiency in the intrinsic pathway factors (factors VIII, IX, XI, and XII). Thus, further testing should be done to confirm this suspicion. Starting the patient on Coumadin, which inhibits vitamin K-dependent clotting factors in the extrinsic pathway, would not be appropriate without further investigation. Repeat aggregation studies would not yield any additional information. Factor assays for the extrinsic and common pathways would not be necessary unless there were other indications for a coagulation disorder.

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