Coagulation disorders (VKCFD)
Vitamin K-dependent clotting factor disorder (VKCFD) is a very rare genetic disorder. This disorder results in decreased production of factors in the blood needed for clotting and therefore a bleeding tendency. Vitamin K administration is the main therapy in VKCFD, although the response may be variable. Other treatment is also provided as required.
Hemorrhagic disease of newborn (vitamin K deficiency bleeding/VKDB)
Vitamin K deficiency in infants can lead to hemorrhagic disease of the newborn, also known as vitamin K deficiency bleeding (VKDB). Although up to half of newborns may have some degree of vitamin K deficiency, serious hemorrhagic disease with bleeding is rare. In cases of true VKDB, bleeding may occur at injection sites, at the umbilicus, or in the gastrointestinal tract. Life-threatening intracranial bleeding (into the head) or retroperitoneal bleeding (in the area behind the lower abdomen) can also occur. Evaluation by a physician is imperative. Because vitamin K given by injection has been shown to prevent VKBD in newborns and young infants, the American Academy of Pediatrics recommends administering a single intramuscular injection of vitamin K1 to all newborns. Dosing by mouth is not considered adequate as prevention, particularly in breastfeeding infants. Initial concerns of cancer risk were never proven and are generally not considered clinically relevant.
Vitamin K deficiency
Vitamin K deficiency is rare in adults but can lead to defective blood clotting and increased bleeding, as well as osteoporosis. People at risk for developing vitamin K deficiency include those with chronic malnutrition (including those with alcohol dependency) or conditions that limit absorption of dietary vitamins, such as biliary obstruction, celiac disease or sprue, ulcerative colitis, regional enteritis, cystic fibrosis, short bowel syndrome, and intestinal resection (particularly of the terminal ileum, where fat-soluble vitamins are absorbed). In addition, some drugs may reduce vitamin K levels by altering liver function or by killing intestinal flora (normal intestinal bacteria) that make vitamin K (for example, antibiotics, salicylates, antiseizure medications, and some sulfa drugs). Evaluation by a physician should be sought.
Warfarin reversal (elevated INR / pre-procedure)
Warfarin is a blood-thinning drug that inhibits vitamin K-dependent clotting factors. Warfarin is prescribed by doctors for people with various conditions, such as atrial fibrillation, artificial heart valves, a history of serious blood clots, clotting disorders (hypercoagulability), and placement of indwelling catheters or ports. Usually, blood tests are done regularly to evaluate the extent of blood thinning, using a test for prothrombin time (PT) or the international normalized ratio (INR). The range for the PT/INR depends on the condition being treated. The PT/INR can become elevated for many reasons and sometimes can get dangerously high and increase the risk of serious bleeding. Patients taking warfarin should be aware of these potential causes, which include many drugs that interact with warfarin, liver disorders, and accidental warfarin overdose. Because the effects of warfarin on anticoagulation are usually delayed by several days, the PT/INR may not increase immediately at the time of overdose. If a person's blood becomes too "thin," management should be under strict medical supervision and may include oral or injected vitamin K to help reverse the effects of warfarin.
Bleeding disorders (prevention of bleeding or thrombotic events in anticoagulant therapy)
Agents that block vitamin K, such as warfarin and phenprocoumon, are often used in anticoagulant therapy. Because dietary intake of vitamin K can affect anticoagulant function, inconsistent levels of vitamin K in the diet may make it difficult to control anticoagulant stability. Some studies suggest that daily, low-dose vitamin K supplementation may help stabilize anticoagulant therapy.
Dietary consumption of vitamin K may be associated with a decreased risk of certain types of cancers. More studies are needed to confirm these results.
A relationship between vitamin K intake and reduced cardiovascular disease risk cannot be confirmed at this time. Further research is needed.
Cystic fibrosis is associated with decreased fat digestion, and suboptimal vitamin K status is common even in patients using vitamin K supplements. More research is needed to determine the clinical benefit of supplementation.
Gastrointestinal disorders (bleeding)
Evidence in support of vitamin K for bleeding associated with gastrointestinal disorders is lacking at this time. Further research is required.
Vitamin K appears to prevent bone resorption, and adequate dietary intake is likely necessary to prevent excess bone loss. Elderly or institutionalized patients may be at particular risk, and adequate intake of vitamin K-rich foods should be maintained. Unless patients have a demonstrated vitamin K deficiency, there is no evidence that additional vitamin K supplementation is helpful. Some studies show that vitamin K supplements may increase bone mineral density and bone strength, while others show that vitamin K has no effect on bone turnover. However, vitamin K may play a role in the prevention and treatment of glucocorticoid-induced bone loss. Furthermore, vitamin D and calcium supplementation may enhance the beneficial effects of vitamin K. Further research is needed to confirm these results.
Hepatocellular carcinoma (recurrent hepatocellular carcinoma prevention)
Infection with the hepatitis C virus (HCV) may lead to hepatocellular carcinoma (HCC), a form of liver cancer. So far, the results from clinical studies are unclear and do not indicate any beneficial effects of vitamin K in preventing HCC recurrence.