A lack of Vitamin K can cause a loss of functionality in Vitamin K-dependent coagulation factors, specifically, factors II, VII, IX, and X. Most often associated with a diet lacking in Vitamin K, it may also present in situations of broad-spectrum antibiotic use, where normal flora in the gut have been eliminated.
As one might expect, treatment involves a diet rich in Vitamin K-containing foods and judicious use of broad-spectrum antibiotics.
Note: The Vitamin K-dependent coagulation factors are also known as the Prothrombin group.