Vitamin K Deficiency

GENERAL PRINCIPLES

Vitamin K deficiency is usually caused by malabsorption states or poor dietary intake, often combined with antibiotic-associated loss of intestinal bacterial colonization. Hepatocytes require vitamin K to complete the #947;-carboxylation-mediated synthesis of clotting factors (X, IX, VII, prothrombin) and the natural anticoagulant proteins C and S.

DIAGNOSIS

A prolonged PT that corrects after a 1:1 mix with normal pooled plasma suggests that a patient has vitamin K deficiency.

TREATMENT

Oral vitamin K replacement (e.g., phytonadione 5 mg PO daily) typically has good absorption in patients who have had poor dietary intake. In patients who have malabsorption, parental vitamin K should be given IV, rather than SC.