From Dr. Jasmina in India: Hello George. I need some thoughts on a case with bleeding. An 8 month old female child was referred for workup for a bleeding disorder. The mother noticed ecchymotic patches over the arms, legs and back over the previous two weeks and a single episode of epistaxis. The platelet count was 565 X 10E9/L. An elder male sib is fine and the parents are asymptomatic.
The PT is 12 s ( n=13–16 s), aPTT is 26 s (n= 26–32 s), Fib is 2.67 (n=2–4).The urea clot solubility test was normal, blood group was B pos.
The VWF antigen assay on 2 occasions a month apart was 184.3 & 133% (n=66–176%, using the kit cuttoffs, since pediatric norms are not available for our population). Done by LIA on the ACL TOP 500 using the Hemosil VWF antigen kit.
The VWF:RCo assay on 2 occasions a month apart gave results of 47.8 & 44.2%. (n=61–240%, using the kit cuttoffs, since pediatric norms are not available for our population). Done by LIA on the ACL TOP 500 using the Hemosil RiCoF kit. Factor VIII level is 131.6% (n=60–160%). Collagen binding, multimer and mutation analysis are not available, and the parents are to still be screened.
1) Is it all right to label this child as VWD Type 2, since neither VWF antigen nor RiCof is <30?
2) When the VWF antigen is not less than 30, but the VWF:RCo is less than the reference range, is it even possible to just say that this child is bleeding with low VWF? I find it hard to reconcile the normal antigen levels, since I understand that low VWF should go as a differential for type 1 VWD.
3) Could acquired VWD be a possibility? Do these kind of cases need to be retested after a couple of years to exclude an acquired VWD?
4) What kind of reference ranges are labs using for the diagnosis of VWD in children, especially if the test are not done on a Stago machine?
Hello, Dr. Jasmina, and thank you for your question and your interesting case. Given the child’s symptoms; slightly elevated or high normal VWF:Ag levels and consistently low VWF:RCo levels, It seems appropriate to reach a presumptive diagnosis of VWD type 2. Acquired VWD is relatively rare and usually secondary to various conditions, however given the nature of VWD, it is appropriate to retest the patient at regular intervals. While you may not have access to confirmatory multimeric analysis, IL offers an immunoassay measuring VWF activity that is separate from the VWF:RCo that may help you confirm the child’s condition. Finally, you can find reference to Dr. Maureen Andrews’ 1990 pediatric reference ranges on the University of Alabama at Birmingham special coag lab web sith at www.uabcoag.net. In the case of an 8-month-old child, the range is similar to the adult range.