Clin Chim Acta 2018 Oct 26;485:272-274. Epub 2018 Jun 26.
University of Virginia Department of Pathology, Charlottesville, VA, United States. Electronic address:
Background: Vitamin K is a vital component within both the intrinsic and extrinsic coagulation cascade as certain factors (II, VII, IX, X and protein C and S) utilize vitamin K as a cofactor during post translational modification. Deficiency of vitamin K can result in the inability to properly form blood clots, both in vivo and in vitro, due to reduced vitamin K dependent factor levels and function. Vitamin K deficiency can result from congenital causes, such as VKOR or CYP2C9 mutations, or acquired causes, such as nutritional deficiencies, antibiotic therapy, or supra-therapeutic warfarin dosing.
Results: In this case we present a patient with multifactorial vitamin K deficiency (due to nutritional defects and multiple genetic mutations in VKOR and CYP2C9) that was exacerbated by antibiotic and warfarin therapy during her hospital admission.
Conclusion: This case displays the importance of genetic testing prior to warfarin dosing and the role antibiotics play in the coagulation cascade.