Extrinsic factor deficiency

Definition

Factor VII deficiency is a disorder that runs in families. It is caused by a lack of enough plasma protein factor VII and leads to abnormal blood clotting (coagulation).

Alternative Names

Causes

This disorder occurs when you lack factor VII, an important clotting protein.

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 VII 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 missing, the chain reaction does not take place normally. In this disorder, bleeding can vary from mild to severe within the same person over time. Bleeding may begin during infancy or childhood. Gastrointestinal and central nervous system bleeding can occur.

The risk factor is a family history of bleeding. The incidence is 1 in 500,000.

Symptoms

• Bleeding of mucous membranes
• Nosebleeds
• Excessive bruising
• Excessive menstrual bleeding
• Bleeding into muscles
• Bleeding into joints

Exams and Tests

• Prolonged prothrombin time
• Normal partial thromboplastin time
• Decreased plasma factor VII activity

Treatment

Patients can control bleeding episodes with normal plasma, concentrates of factor VII, or genetically produced (recombinant) factor VII. People need frequent treatment during bleeding episodes because factor VII does not last for long. Women can control menstrual bleeding with oral contraceptives. An activated concentrate of factor VII called Novo-7 can also be used.

Support Groups

The stress of illness can often be helped by joining a support group where members share common experiences and problems. See hemophilia - resources.

Outlook (Prognosis)

The outcome can be good with proper treatment.

Possible Complications

• Hemorrhage
• Stroke or other nervous system problems from central nervous system bleeding
• Joint problems in severe cases when bleeding happens often

When to Contact a Medical Professional

Go to the emergency room or call the local emergency number (such as 911) if you have severe, unexplained bleeding.

Prevention

This disorder is passed through families (inherited). There is no known prevention.

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

Levi M, Peters M, Büller HR. Efficacy and safety of recombinant factor VIIa for treatment of severe bleeding: A systematic review. Crit Care Med. April 2005;33:883-890.

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