From Dr. Samir Patel: George, I was wondering if I could get some input from you or any of the other readers regarding a patient in my clinic. This is a 52 year old woman with history of multiple surgeries (dental, orthopedic) and with mixed history of intraoperative bleeding, late bleeding, and no bleeding. She was sent due to history and a prolonged aPTT (PTT). I have performed an extensive workup but have not been able to identify the cause of the prolongation and am not sure what to recommend regarding further workup and future surgery.
- PT/INR, normal
- PTT 46.2s; mixing studies: 1:1 mix 38.1s; 1:1 at 60 minutes 39.0s
- Lupus AC profile: PTT 45.8s, PTT–LA 51.5s, hexagonal phase phospholipid, 7.2s, DRVVT 28.2s. Comment: no lupus anticoagulant was detected. Results are consistent with presence of one or more factor specific inhibitors. Since DRVVT was within the normal limits, the factors in question are VIII, IX, XI, XII and the contact factors.
- Thrombin time, 14.3s
- Fibrinogen, 342 mg/dL
- Factor II, 102%; factor V, 109%; factor VIII, 193%; factor IX, 487%, 436%; factor X, 112%; factor XI, 94%; factor XII, 90%, prekallikrien 141%, 76%; high molecular weight kininogen, 75%
- Euglobulin lysis, normal
- Reptilase time, 17.7s
- Antiphosphatidyl serine antibodies negative, anticardiolipin antibodies negative
Unless I’m misinterpreting these results, lupus anticoagulant testing is negative but none of the factor assays show any abnormalities or presence of an inhibitor that would explain the prolongation of the PTT. Please help, thanks. Samir
Hello, Dr. Patel, and thank you for your interesting case. Though your PTT mixing studies appear to indicate an inhibitor, the results are somewhat borderline positive, and may bear repeating. While we await comments from our participants, may I suggest you also consider a factor XIII assay, as factor XIII deficiency associates with intermittent and delayed bleeding? Also, though perhaps less likely, you may wish to check on platelet function. Looking forward to additional comments!