Question

A 16-month-old male is brought to his pediatrician for a check-up. His mom has noticed that he seems to bruise easily and it has become more apparent since he has started walking and climbing. Physical exam reveals a few ecchymoses but is otherwise unremarkable. Questioning revealed that two maternal uncles were “bleeders”. The child is not on any medications. A CBC was ordered—the results were as expected for a child his age. A coagulation screening panel was also ordered. The results are as follows:

Coagulation Screening Panel

PT = 13.4 seconds (reference range 12.0–14.2 seconds)

APTT = 44 seconds (reference range 28.0–35.5 seconds)

TT = 13 seconds (reference range 11.0–16.0 seconds)

Platelet count: 360.0 x 10⁹/L (reference range 150.0–450.0 x 10⁹/L)

Reflex Testing

(1) Mixing Study APTT: 35.0 seconds (normal 28.0–35.5 seconds)

(2) Factor Assays:

   F VIII = 4% (reference 50–150%)

   F IX= 128% (reference 50–150%)

   F XI = 112% (reference 50–150%)

(3) Bleeding Time: 4 minutes (reference range 1–9 minutes)

QUESTIONS

   1. Discuss this patient’s physical exam findings, clinical history, and family history with

   regards to the evaluation for bleeding disorders.

   2. Discuss each of the four tests that are part of the screening panel including (a) why

   each test was included in the panel and (b) how each test is performed. Be specific

   in your answer.

   3. Why was reflex testing performed on this patient?

   4. Mixing Studies

       (a) Discuss the purpose of a mixing study.

       (b) How are mixing studies performed?

       (c) How would you interpret this patient’s mixing study?

   5. Factor Assays

       (a) Describe how factor assays are performed.

       (b) How would you interpret this patient’s factor assay studies?

   6. Bleeding Time

       (a) What is the purpose of performing a bleeding time?

       (b) How is the test performed?

       (c) How would you interpret this patient’s bleeding time?

   7. Based on the history, physical exam, and coagulation testing performed, what is this

   patient’s most likely diagnosis? Justify your answer.

   8. What therapy is typically used for bleeding episodes in individuals with this disorder?

   9. Platelet aggregation studies may be part of the coagulation reflex testing

      protocol.

       (a) Why are platelet aggregation studies performed?

          (b) Describe how platelet aggregation studies are performed.

       (c) Would a platelet aggregation study be needed on this patient? Justify your

          answer.

Answer 1

1. The patient shows genetic link to a coagulation disorder.

The patient is a male and easily susceptible to bruising and have echymoses

The coagulation screening shows high APTT time with normal PT and bleeding time.

Factor Assay shows low levels of factor VIII.

All these are suggestive of Haemophilia A