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Prekallikrein Deficiency and Nosebleeds

From Kim Kinney at Clarian in Indianapolis:

We have a case of a 2-year-old girl with spontaneous nose bleeds and 80-100 second partial thromboplastin times (PTTs).  Normal von Willebrand factor VWF test results, normal platelet studies, but less than 1% prekallikrein (PK, Fletcher factor).  She is on Amicar as needed. Very few cases listed in the literature–not sure if the bleeding episodes are truly spontaneous–they seem to always happen at night.  Mother denies digital exploration.

Kim and I discussed this case when I was at Indiana University/Purdue University Medical School on September 16 for grand rounds, and I thank her for reminding me so we could post it. At the time I expressed skepticism that the child’s PK deficiency could account for her nosebleeds, as there is no reported bleeding association. I still maintain this skepticism, and also suggest that despite the VWF and platelet studies, chronic spontaneous nosebleeds more likely arise from a primary coagulation deficiency such as a platelet function disorder, not a coagulopathy. We didn’t know if the girl had other indications of bleeding such as easy bruising, but suggested this could be related to her vasculature or to unreported habitual “digital exploration.”

I’ll also take this opportunity to mention again the “poor man’s” PK assay: ten-minute (instead of 3-minute) incubation with kaolin or Celite-activated PTT reagent (but not ellagic acid) corrects the PTT. The reference for this is Hattersley PG, Hayse D: The effect of increased contact activation time on the activated partial thromboplastin time. Am J Clin Pathol 1976; 66:479. We once used this approach at UAB to establish a PK deficiency and eliminate the need for a send-out.

I’m sure this is a pure coincidence, but we’ve had three discussions on PK in the past week and a half, and I just posted a Stago STAR-based PK protocol on October 2. Has anyone on the list seen a bleeding-related PK deficiency? Please send my your details. Geo.

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