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vitamin K deficiency

Etiology: 1) absent intake of vitamin K with or without antibiotics 2) malabsorption syndromes 3) warfarin 4) ingestion of new 'super warfarins' used in rat poisons 5) genetic defects in vitamin K-dependent clotting factors Pathology: 1) defect in post-translational modifications of coagulation factors, factor II, factor VII, factor IX & factor X by vitamin-K dependent carboxylase 2) functional activity of coagulation factors disappear from plasma in order: factor VII < factor IX < factor X < factor II (increasing 1/2 lives) 3) vitamin K stores are limited Genetics: - associated with defects in VKORC1 gene Laboratory: 1) prolonged prothrombin time (PT) 2) frequently aPTT is also prolonged 3) plasma coagulation factor II activity, factor VII activity, factor IX activity & factor X activity (diminished activities) 4) factor V activity is diminished in liver failure, but not vitamin K deficiency (compare with factor VII) Management: 1) ingestion of new 'super warfarins' (rat poison) a) 'super warfarins' have very long 1/2 lives (months) b) unresponsive to usual doses of vitamin K 2) vitamin K a) 0.5-1.0 mg IV generally corrects coagulation defect b) vitamin K 10 mg SC QD for 3 days is common practice

Related

coagulation factor IX; Christmas factor; plasma thromboplastin component; PTC; contains: coagulation factor IXa light chain; coagulation factor IXa heavy chain (F9) coagulation factor VII; proconvertin; serum prothrombin conversion accelerator; SPCA; Eptacog alfa; contains: factor VII light chain; factor VII heavy chain (F7) coagulation factor X; Stuart factor; Stuart-Prower factor; contains: factor X light chain; factor X heavy chain; activated factor Xa heavy chain (F10) prothrombin; coagulation factor II; contains: activation peptide fragment 1; activation peptide fragment 2; thrombin light chain; thrombin heavy chain (F2) vitamin K

General

hypovitaminosis (vitamin deficiency) coagulation factor deficiency

Database Correlations

OMIM 607473

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 18. American College of Physicians, Philadelphia 1998, 2018.
  2. Brenner B, Kuperman AA, Watzka M, Oldenburg J. Vitamin K-dependent coagulation factors deficiency. Semin Thromb Hemost. 2009 Jun;35(4):439-46. Review. PMID: 19598072