Question of the week # 297

297) A 64 year old man is seen in the office for pre-operative evaluation of right inguinal hernia repair. His past medical history is significant for diabetes and recurrent right foot cellulitis. His most recent episode of right foot cellulitis was 2 weeks ago for which he received a 2 week course of oral antibiotics. His surgery is scheduled within one week. On examination, he is afebrile. He has reducible right inguinal hernia and bilateral lower extremity stasis dermatitis. His laboratory investigations reveal:

Platelet Count 240k/μl ( Normal 150–400k/μl)

Prothrombin time 22 seconds ( Normal 10 to 13 secs)

Partial Thromboplastin time : 34 sec ( Normal 22 to 37 secs)

Which of the following is the most appropriate action at this time?

A) Obtain PTT mixing studies

B) Administer Oral Vitamin K

C) Intravenous Fresh Frozen Plasma

D) Intravenous Factor VIII

E) Von Willebrand Factor Assay

13 Responses

  1. give ffp

  2. a

  3. C

  4. E

  5. c

  6. An isolated PT prolongation suggests a deficiency or inhibition of the extrinsic pathway (FVII), but mild factor X, V, and II deficiencies are also possible causes. Prolongation of both aPTT and PT suggests a deficiency or inhibition of the common pathway coagulation factors (factor X, V, and II), or a qualitative or quantitative fibrinogen defect.

    When evaluating an unexpected prolonged aPTT and/or PT result, the first step is to rule out preanalytical causes of inaccuracy(1). Anticoagulant contamination due to blood collection from a venous or arterial line flushed with heparin is a common artifact, and although most commercial PT reagents contain a substance capable of neutralizing approximately 2 U/mL of heparin, this capacity can be overwhelmed if blood is collected from heparin-containing catheters. Other preanalytical variables include the use of collection tubes containing a higher sodium citrate anticoagulant concentration (3.8% instead of 3.2%), hemolyzed samples interfering with photo-optical clot detection methods, and a prolonged time lapse between specimen collection and performance of aPTT (>4 hours) and PT (>24 hours) assays. An increase of the citrate:plasma ratio, which decreases the ionized calcium concentration [e.g., in samples from patients with high hematocrit (>55%) or samples collected in underfilled collection tubes] may produce erroneously prolonged PT and aPTT results.

    The second step in evaluating an unexpected prolonged aPTT and/or PT result should be to repeat the aPTT or PT assay, taking care to eliminate potential sources of preanalytical artifact. If the screening coagulation test continues to show prolonged times, the third step is to perform a mixing study on a 50:50 mixture of patient plasma and normal pooled plasma. Correction to within the reference interval is consistent with a deficiency of one or more factors, and no or partial correction is consistent with inhibitor activity due to an anticoagulant, a factor-specific neutralizing antibody, or a nonspecific lupus anticoagulant.

    When FVII replacement is necessary in deficient patients, options include fresh-frozen plasma, prothrombin complex concentrates, and recombinant FVIIa.

    So in this particular case and answers, the answer is C if there is any bleding complication during surgery.

  7. But with the history of antibiotic therapy, an elevation of serum PT and PTT mya found in vitamine K deficiency,. However, it is not uncommon for these patients to have an elevated PT level and normal PTT. So I will like to change the answer and is B,and in one week he will be ready for the surgery.

  8. A…since no option is provided for repeating the test (analytic errors: anticoagulant contamination, long delay from collection to measurement), a mixing study is needed. If PT is corrected in the mixing study, check clotting factor (Factor VII in this case is most likely due to extrinsic pathway abnormality). If PT is not corrected, then it could be due to anticoagulant (including lupus)

  9. bbb

  10. Answer B

    This patient had ORAL AB for 2 weeks . This might lead to mild increased in PT time due to the fact that Vit K production requires certain normal microflora in our gut to synthesize them .

    Patient is old . No history of abnormal bleeding . no family history . We can safely rule out any genetic inheritance like hemophilia or Von willebrand . if he were to have those . He should know them by now . It would not wait until 64 y/o in order to manifest . Well .. in real life you might get acquired form . But here i guessed not . haha

    Surgery is in 1 week time . I think plenty of time for for liver to regenerate the coagulation factor . Vit K is sufficient .

    If it says surgery now . Then FFP is the right answer .

    Just my 2cents. Please do correct me if I’m wrong . thanks

    • This patient has isolated prolong PT without bleeding manifestation and history taking antibiotics. D/Dx – Factors deficiency Factor XII, XI, (if he has hemophilia, he should have bleeding problem in childhood), vit k dependent factors deficiency, lupus anticoagulant. Since Lupus anticoagulant can be acquired in older age and it is associated with thrombosis, we need to exclude it especially in pre op patient. He might need prophylaxis for DVT. Another differential diagnosis is vit k dependent clotting factors deficiency because of recent antibiotics. I dont think it is reasonable to assume factor deficiency because of history of antibiotics. So I will do mixing studies first.if PT is corrected by the mixing studies, he has factor deficiency and plan to give vit K orally. It takes only 24-48 hours to get action of vit k on PT. If mixing studies does not correct the PT, we will do vdrl, russell viper venom screen to confirm lupus antibody. Then this patient will need heparin before surgery.

      • Answer A)

  11. Ooops: A) PTT mixing study…?? PTT is normal. I want to do PT mixing study. If there is no option for PT mixing study, then I will chose oral vit K.
    Answer B

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