Clotting factor deficiency, which is asymptomatic?
Ans. c (XII) (Ref. H - 18th/ch. 61)FACTOR XII DEFICIENCYIt cause laboratory abnormalities but no clinical bleeding. Despite dramatic prolongation of the PTT often to greater than 100 s, deficient individuals have normal hemostasis and can undergo major surgery without plasma replacement therapy. Direct activation of factor IX by the tissue factor-Vlla complex may bypass this defective step in coagulation.0DEFICIENCIES IN FACTORS V, VII, X, AND PROTHROMBIN (FACTOR H)Deficiencies in factors V, VII, X, and prothrombin (factor II) are exceedingly rare autosomal recessive disorders. Spontaneous or posttraumatic musculoskeletal bleeding or menorrhagia* can occur with these deficiencies, but hemarthroses are uncommon. FFP is the appropriate therapy.Factor XI DeficiencyInherited as an autosomal recessive trait and is especially common in Ashkenazi Jews. In contrast to deficiency in factors VIII and IX, the correlation between factor level and propensity to bleed is not as precise, spontaneous bleeding is less, and hemarthroses are rare. Many patients with factor XI deficiency present with posttraumatic bleeding or with bleeding in the perioperative period, and occasional factor Xl-deficient women have menorrhagia. Daily infusions of FFP are sufficient, since the half-life of factor XI is approx 24 h.FACTOR XIH DEFICIENCY (extremely rare)Factor XIII is a transglutaminase that stabilizes fibrin clots by forming e-amino-y-glutamyl cross-links between adjacent a and alpha chains of fibrin. Patients usually bleed in the neonatal period from their umbilical stump or circumcision.In addition to hemorrhage, these patients may have poor wound healing, a high incidence of infertility among males and abortion among affected females, and a high incidence of intracerebral hemorrhage. Several drugs, including isoniazid, may bind to cross-linking sites on fibrinogen and mimic factor XIII deficiency by blocking enzyme activity. Normal hemostasis requires only 1% of normal enzyme activity; a single infusion of FFP or a purified factor XHI-rich product derived from human placenta called Fibrogammin is effective. Factor XIII has a 14-day half-life.Hemorrhagic disordersDisorderPlatelet countBleeding timePTcPTTQualitative platelet defects-|--Thrombocytopenia||--Hemophilia A or B---|von Willebrand's disease-|-|DIC||||
II
V
XII
XI
Blood