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Factor II Deficiency
(Prothrombin)
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What Is
It?
Prothrombin is a vitamin K-dependent proenzyme that functions in
coagulation. There are two types of this deficiency, a congenital version
called hypoprothrombinemia, and an acquired version called dyspothrombinemia.
A life-long bleeding disorder when congenital, it's extremely rare. In fact,
only 30 cases of this hereditary clotting factor defect have been identified
in the whole world.
Acquired factor II deficiency is more common. It results from vitamin K
deficiency, severe liver disease, and therapeutic use of anticoagulant
drugs. Risk factors for vitamin K deficiency are prolonged use of
antibiotics, bile duct obstruction, and intestinal malabsorption (inadequate
absorption of nutrients from the intestinal tract) disorders. Some newborns
are born with vitamin K deficiency.
If it is caused by liver disease, the outcome depends on the control of the
liver problem. Vitamin K administration will correct vitamin K deficiency.
Either form may lead to severe bruising, excessive menstrual bleeding,
postoperative hemorrhage, and occasionally muscle bleeds.
Inheritance Pattern
A congenital factor II deficiency is a very rare inherited disorder that
results in deficient blood clotting. The disorder is not sex-linked as is
hemophilia. It affects both males and females with equal frequency. It is
autosomal recessive, which means if the clotting defect is inherited from a
parent, the child will be a genetic carrier of the condition, but may or may
not have symptoms. A family history of bleeding disorder is a risk factor.
Symptoms & Diagnosis
Signs and symptoms vary with the level of prothrombin. Patients with levels
over 50% of normal have no bleeding problems, whereas people with levels
from 2% to 50% may easily bruise, or suffer from epistaxis, menorrhagia,
muscle hemorrhages, postpartum hemorrhages, and hemorrhage following surgery
and trauma.
Symptoms include:
• Umbilical cord bleeding at birth
• Nose bleeds
• Abnormal menstrual bleeding
• Abnormal bleeding after delivery
• Bleeding after trauma
• Bleeding after surgery
• Easy bruising
Signs and Tests:
• Prolonged prothrombin time
• Prolonged partial thromboplastin time
• Factor II assay showing decreased activity
• Levels of prothrombin ranging from 2% to 50% of normal
Treatments
Treatment depends on the severity of the disorder and the type of bleeding.
Mild cases may be treated with plasma infusion. Loss of blood can be
controlled by infusions of fresh frozen plasma. Severe factor II
deficiencies may be treated with prothrombin complex concentrates (PCCs).
When necessary, it can be treated with plasma replacement therapy. Effective
control of hemorrhage is achieved when prothrombin levels are at 30% to 50%
of normal.
Genetic counseling may be helpful in the case of congenital disorders. The
use of vitamin K in malabsorption and long-term antibiotic use may be
preventative.
If the disorder is caused by vitamin K deficiency, then vitamin K is
prescribed. Diagnosis of a bleeding disorder is important so that
precautionary measures can be taken if surgery is needed or anticipated.
The National Hemophilia Foundation's Medical and Scientific Advisory Council
(MASAC) made recommendations for treatment of factor II deficiency in
November of 1999. They include:
• Prothrombin complex concentrates (PCCs) can be used, but these products
vary considerably in the amount of factors they contain.
• Fresh frozen plasma can be used as along as it is processed to reduce the
risk of viral infection.
Complications
Bleeding has to be controlled in instances of trauma or surgery or else
bleeding into the brain or skull can occur. |
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