docnikki
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A 28-year-old female develops severe uterine bleeding with coagulation profile abnormalities eight hours after a successful delivery. She does not have any prior medical history, and the pregnancy was uncomplicated. She does not take any medications at home, except for multivitamins. The family history is unremarkable for any bleeding disorders. She has had tooth extractions in the past with no increase in bleeding.
On physical examination the patient presents as an anxious, nervous female, that looks her stated age. Her temperature is 97.8 F, blood pressure is 110/50 mm Hg, heart rate is 90/min, and the respiratory rate is 16/min. Her skin is pale. The uterus is enlarged, soft, and mildly painful on palpation. There are no external tears on vaginal exam. The amount of bleeding increases during palpation of the uterus.
Laboratory studies show the following results:
WBC 5,800/mm3; hemoglobin 9.8 g/dL; hematocrit 32.1 %, platelets 188,000/mm3; PT 12.4 seconds, INR 0.9, PTT 56 seconds. Bleeding time is normal. Fibrinogen 330 mg/mL; factor VIII: C level 22%.
The bleeding started three hours ago. During this time, the patient has received two units of packed red blood cells and six units of fresh frozen plasma (FFP), but the PTT remains elevated, and the bleeding still continues. Which test would be most useful in this situation?
(A) Von Willebrand's factor level
(B) Antiphospholipid antibody
(C) Russell viper venom (RVV) time
(D) PTT 1:1 mixing test
[font size="2"](E) Fibrin degradation products[/font]
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| farnsworth
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D
the patient has an acquired coagulation disorder: autoantibodies against FVIII (not uncommon postpartum women)
This affects the PTT only. Since the PTT is prolonged > 48 secs, a PTT 1:1 mixing test should be done
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| Korotkoff
Forum Senior
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What is PTT 1:1 mixing test? .....I gotta run.
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| doc_clotaire
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Agree with D .. 
PTT 1:1 mixing test can help with the diagnosis of an abnormal PTT. The mixing test takes patient plasma and mixes it—usually 1:1—with control plasma, and then the PTT of the mixture is determined. A correction of the PTT in the mixture identifies a deficiency of one or more factors of the intrinsic pathway.
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| docnikki
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Very good!
Answer:
([font size="2"]D) PTT 1:1 mixing test[/font]
Explanation:
This patient developed factor VIII antibodies, which may happen postpartum or even sometimes without an obvious underlying cause. This can also occur in 15% of patients with factor VIII hemophilia, who have received infusions of fresh frozen plasma (FFP) or factor VIII replacement. In this disorder, the bleeding is usually severe, there is a decreased factor VIII level, and the PTT is prolonged. The fibrinogen level, PTT, and platelet count are not affected.
A plasma mixing test will show the presence of an inhibitor by the failure of normal plasma to correct the prolonged PTT. This test may require incubation for 2 to 4 hours. Factor VIII coagulant levels are low, which should not happen in von Willebrand's disease.
Hemophilia A is extremely unlikely in a woman because she would have to be homozygous recessive for the X-linked disorder. Factor VIII antibodies should be suspected in any patient with acquired severe bleeding and a prolonged PTT. The diagnosis is confirmed by mixing tests and by a failure of factor VIII concentrates to raise factor VIII:C levels.
Von Willebrand's disease is associated with mild mucosal bleeding. The measurement of von Willebrand's factor level will help you to distinguish between hemophilia A and von Willebrand's disease but won't explain why the coagulation profile was not corrected by transfusions of FFP.
Lupus anticoagulant is not associated with bleeding, unless a second disorder, such as thrombocytopenia or hypothrombinemia is present. Most commonly, it presents with thrombosis. Lupus anticoagulant also gives a prolonged PTT, and the mixing study will also fail to correct.
The Russell venom viper test is a more sensitive assay to demonstrate the presence of a lupus anticoagulant.
An antiphospholipid antibody is usually positive. Anticardiolipins are a related antiphospholipid antibody that can be detected by a separate assay.
Fibrin degradation products are elevated in DIC, which also presents with hypofibrinogenemia. D-dimer is the most sensitive of the fibrin-degradation products. The patient is usually seriously ill and has a low platelet count and elevation of the PT, as well as PTT. Bleeding may occur at any site, but spontaneous bleeding and oozing at venipuncture sites are important clues to the diagnosis.
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| sherry39
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b......coz leukocytes n hb is low as well
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