Factor II deficiency

Definition

Factor II deficiency is a blood clotting (coagulation) problem caused by a lack of a substance (prothrombin) that is needed for blod to clot.

Alternative Names

Causes

When you bleed, the body launches a series of activities that help the blood clot. This is called the coagulation cascade. The process involves special proteins called coagulation factors. (Factor II is a coagulation factor.) Each factor's reaction triggers the next reaction. The final product of the coagulation cascade is the blood clot.

When certain coagulation factors are too low or missing, the chain reaction does not take place normally. In this disorder, bleeding ranges from mild to severe.

A congenital factor II deficiency is a very rare disorder that runs in families (inherited). It results in poor blood clotting. Both parents must be carriers to pass it to their children. A family history of a bleeding disorder is a risk factor.

Acquired factor II deficiency is common and results from a lack (deficiency) of vitamin K, severe liver disease, and use of drugs that prevent clotting (anticoagulants). Risk factors for vitamin K deficiency are long-term use of antibiotics, bile duct obstruction, and poor absorption of nutrients from the intestinal tract (intestinal malabsorption). Some newborns are born with vitamin K deficiency.

References

Hoffman R, Benz E, Shattil S, Furie B, Cohen H. Hematology: Basic Principles and Practice. 4th ed. Philadelphia, Pa: Churchill Livingstone; 2004.

McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. St. Louis, Mo: WB Saunders; 2006: 741.