Question

A 2-year-old boy fell from a backyard gym set. His shoulder and upper arm became very swollen shortly after the fall. The boy’s mother took him to the emergency department a few hours after th incident because he was complaining of pain. On physical examination, the physician noted that large hematoma had formed in the upper part of the boy’s right arm. There was no history of surgery (he had not been circumcised), injury, or illness.

The boy was receiving no medication. Emergency department treatment consisted of aspirating the hematoma Subsequent to this treatment, the boy began to bleed extensively. He was admitted to the hospital. The following laboratory tests were ordered: a hemoglobin and hematocrit, platelet count, and bleeding time. Because the bleeding continued, a type and crossmatch for two units of fresh blood were ordered on a standby basis. Additional information from the mother revealed that the boy’s cousin had “bleeding problem.”
Laboratory Data
Hemoglobin 8.0 g/L
Hematocrit 26%
Platelet count 200 × 109/L (normal, 150 to 450 × 109/L)
Bleeding time 5 minutes (normal, 3 to 8 minutes)
Subsequent coagulation profile tests were ordered before the transfusion of two units of fresh whole blood.
The results of these tests were as follows:
PT 12 seconds (normal, 11 to 15 seconds)
aPTT 60 seconds (normal, 28 to 35 seconds)
Thrombin time–reptilase method 20 seconds (normal, 18 to 22 seconds)


Questions
1. Do the laboratory data support a diagnosis of a disorder of hemostasis? Which disorder if applicable is to be suspected above
2. What types of disorders can be preliminarily identified by the tests that were performed?
3. What is Mixing test, and how relevant will it be in this patient’s diagnosis?
4. What confirmatory tests must be done in this case?
5. How could the presence of a Lupus anticoagulant affect the patients results if present?
6. What is a lupus anticoagulant?

Answer 1

1. Yes the results of Partial thromboplastin time indicates that there is a coagulation defect in the child's bleeding.

2. If we look closely into this case, we will find that the platelet count of the patient is normal. In fact the bleeding time indicates that the platelets are not responsible for this bleeding disorder. There is no malformation of fibrinogen or other anticoagulant. However, the presence of increased APTT while normal PT indicates deficiency of VIII, IX, XI or XII (any of them)

3. If either the PT or PTT are abnormal or prolonged, then the normal question arises whether the abnormal test result is due to a clotting factor deficiency or due to an inhibitor. In a mixing test, plasma of the patient is mixed with normal plasma and then the mixture is incubated. After that, aPTT is repeated on the mixture. PT measures the integrity of extrinsic and the common pathway while PTT measures the integrity of the intrinsic (VIII, IX, XI or XII) and common pathway. When the PTT is prolonged, it is done twice. If the PTT normalizes with mixing we are dealing with factors deficiency which are factor VIII, IX, XI or XII (any of them). If PTT does not normalizes, then it can be a case of lupus anticoagulant.

4. Screening test, factor assay and factor substitution test can be vital for this patient to understand the actual factor deficiency.

5. If there is a presence of a Lupus anticoagulant, then the patients result of anticoagulation monitoring test is undependable and other alternative testing must be performed for monitoring.

6. Lupus anticoagulant are immunoglobulins that are neither an anticoagulant nor an indication of having a Lupus. Lupus anticoagulant is procoagulant and not an anticoagulant. It's presence in the blood increases the risk of thrombosis and antiphospholipid antibody syndrome that can result in organ failure, pregnancy complications and blood clot formation.