Vitamin K Deficiency
The most common causes of vitamin K deficiency are insufficient dietary intake, inadequate absorption, and decreased storage of the vitamin due to liver disease, but it may also be caused by decreased production in the intestines.
- Dietary deficiency of vitamin K in the U.S., though rare in healthy individuals, is relatively common in those who are severely ill or who have certain chronic conditions. For example, it is often seen in patients admitted to intensive care units, cancer patients on chemotherapy, chronic dialysis patients, and patients who are at risk for malnutrition, such as those with a poor diet associated with alcohol or drug abuse.
- Malabsorption, especially impaired absorption of fats due to diseases such as cystic fibrosis, celiac disease, chronic pancreatitis or Crohn's disease, may also cause vitamin K deficiency. Choleostatic liver diseases such as a bile duct obstruction or primary biliary cirrhosis can also lead to malabsorption and a deficiency in vitamin K.
- Some medications, such as antibiotics, aspirin (salicylates), and anti-seizure medications can interfere with the absorption of vitamin K1, decrease the quantity of K2 produced in the intestines, or increase the body's requirements for vitamin K.
- Deficiencies in newborns are associated with hemorrhagic disease of the newborn (also called vitamin K deficiency bleeding or VKDB). This can cause bleeding and bruising and, in severe cases, can lead to fatal bleeding into the brain. VKDB used to be a relatively common occurrence as newborns have small stores of vitamin K when they are born, their intestines do not yet have established normal flora, and breast milk does not provide them with much vitamin K. In addition, if the newborn's mother takes certain drugs during pregnancy, such as anti-seizure medications, then the infant may be vitamin K deficient at birth. These situations have now been largely resolved with the routine practice of administering a vitamin K shot to all newborns shortly after birth as recommended by the American Academy of Pediatrics. When surgeries are necessary, the infants may also be given vitamin K before the procedure to prevent excessive bleeding.