Most common congenital bleeding disorder?
Correct Answer: Von Willebrand disease
Description: Ans. A. von Willebrand disease. (Ref. H - 17th / pg. 723)Harrison's 17th / pg. 723............ vWD is the most common inherited bleeding disorder.VON WILLEBRAND DISEASE# vWF serves two roles: (1) as the major adhesion mole- cule that tethers the platelet to the exposed subendothelium; and (2) as the binding protein for FVIII, resulting in significant prolongation of the FVIII half-life in circulation.# The platelet-adhesive function of vWF is critically dependent on the presence of large vWF multimers, while FVIII binding is not. Most of the symptoms of vWD are "platelet-like" except in more severe vWD when the FVIII is low enough to produce symptoms similar to those found in Factor VIII deficiency (hemophilia A).# vWD has been classified into three major types:TypeaPTTvWF AntigenvWF ActivityFVIII ActivityMultimer1NI or ||||Normal distribution, decreased in quantity2ANI or |||||Loss of high and intermediate MW multimers2B (with Decreased platelets)NI or |||||Loss of high MW multimers2MNI or |||||Normal distribution, decreased in quantity2N ||NI or |NI or |||Normal distribution3||||||||Absent# Acquired vWD is a rare disorder, most commonly seen in patients with underlying lymphoproliferative disorders, including monoclonal gammopathies of undetermined significance (MGUS), multiple myeloma, and Waldenstrom's macroglobulinemia. It is seen most commonly in the setting of MGUS and should be suspected in patients, particularly elderly patients, with a new onset of severe mucosal bleeding symptoms. Heyde's syndrome (aortic stenosis with GI bleeding) is attributed to the presence of angiodysplasia of the GI tract in patients with aortic stenosis. Acquired type 2 vWD noted in it, but return when the stenotic valve is replaced.von Willebrand diseasePcBtPtPttmecHanism and comments-|--s|Intrinsic pathway coagulation defect : |vWF -normal or | PTT (depends on severity; vWF acts to carry/protect factor VIII).Defect in platelet plug formation: |vWF -defect in platelet-to-vWF adhesion.Mild but most common inherited bleeding disorder. Autosomal dominant. Diagnosed in most cases by ristocetin cofactor assay (|agglutination is diagnostic). Treatment: DDAVP, which releases vWF stored in endothelium.# Rx:- The mainstay of Rx for type 1 vWD is DDAVP, or desmopressin, which results in release of vWF and FVIII from endothelial stores.6 DDAVP can be given intravenously or by an intra-nasal spray (1.5 mg/mL). The peak activity when given IVly is 30 min, while it is 2 h when given intranasally.- Antifibrinolytic therapy, using either epsilon-aminocaproic acid or tranexamic acid, is an important therapy, either alone or in an adjunctive capacity, particularly for the prevention or Rx of mucosal bleeding. These agents are particularly useful in prophylaxis for dental procedures, with DDAVP for dental extractions and tonsillectomy, menorrhagia, and prostate procedures. It is contraindicated in the setting of upper urinary tract bleeding, due to the risk of ureteral obstruction.
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