What is factor II (prothrombin) deficiency?
Factor II (also called prothrombin) deficiency is an inherited bleeding disorder that is caused by a problem with factor II. Because the body produces less prothrombin than it should, or because the prothrombin is not working properly, the clotting reaction is blocked prematurely and the blood clot does not form.
Factor II deficiency is an autosomal recessive disorder, which means that both parents must carry the defective gene in order to pass it on to their child. It also means that the disorder affects both males and females. Factor II deficiency is very rare, but like all autosomal recessive disorders, it is found more frequently in areas of the world where marriage between close relatives is common.
Factor II deficiency may be inherited with other factor deficiencies. It can also be acquired later in life as a result of liver disease, vitamin K deficiency, or certain medications such as the blood-thinning drug Coumadin®. Acquired factor II deficiency is more common than the inherited form.
The symptoms of factor II deficiency are different for everyone. As a general rule, the less factor II a person has in his/her blood, the more frequent and/or severe the symptoms.
- nosebleeds (epistaxis)
- easy bruising
- heavy or prolonged menstrual bleeding (menorrhagia)
- bleeding into joints (hemarthrosis)
- muscle bleeds
- bleeding in the mouth, particularly after dental surgery or tooth extraction
Other reported symptoms
- bleeding in the gut (gastrointestinal hemorrhage)
- bleeding from the umbilical cord stump at birth
- abnormal bleeding during or after injury, surgery, or childbirth
- bleeding in the central nervous system (the brain and spinal cord)
- blood in urine (hematuria)
Factor II deficiency is diagnosed by a variety of blood tests. The doctor will need to measure the amount of factors II, V, VII, and X in the blood. Diagnostic tests should be performed by a specialist at a haemophilia/bleeding disorders treatment centre.
There are two treatments available for factor II deficiency. Both are made from human plasma.
- Prothrombin complex concentrates (PCCs)
- Fresh frozen plasma (FFP)
Excessive menstrual bleeding in women with factor II deficiency may be controlled with hormonal contraceptives (birth control pills), intra-uterine drugs (IUDs), or antifibrinolytic drugs.