Laboratory assessment of vitamin K status.

Vitamin K is required for the ɣ-carboxylation of specific glutamic acid residues within the Gla domain of the 17 vitamin K-dependent proteins (VKDPs). The timely detection and correction of vitamin K deficiency can protect against bleeding. Vitamin K also plays a role in bone metabolism and vascular calcification.

Superwarfarin poisoning and its management.

Difenacoum is a long-acting superwarfarin-type anticoagulant that exerts its effect through inhibiting vitamin K 2,3-epoxide reductase. Inhibition of this enzyme leads to reduced bioavailability of the metabolically active form of vitamin K resulting in decreased production of vitamin K-dependent proteins including coagulation factors II, VII, IX and X. A 45-year-old woman with psychiatric illness presented with haematuria.