Extrinsic factor deficiency
Factor VII deficiency is an inherited disorder that causes abnormal blood clotting (coagulation), resulting from a deficiency of the plasma protein factor VII.
Causes, incidence, and risk factors
This disorder is caused by an inherited deficiency of factor VII, an important clotting protein. Normal blood coagulation is a complex process involving as many as 20 different plasma proteins, which are known as blood coagulation factors. A series of complex chemical reactions using these factors takes place very rapidly to form an insoluble protein called fibrin that stops bleeding.
When certain coagulation factors are deficient or 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. A history of bleeding may occur in 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.
- Bleeding of mucous membranes
- Excessive bruising
- Excessive menstrual bleeding
- Bleeding into muscles
- Bleeding into joints
Signs and tests
- Prolonged prothrombin time
- Normal partial thromboplastin time
- Decreased plasma factor VII activity
Bleeding episodes can be controlled with normal plasma, concentrates containing factor VII, or recombinant factor VII. During bleeding episodes, frequent treatment is needed because the life span of factor VII is short. Menstrual bleeding can be controlled by the use of oral contraceptives.
The stress of illness can often be helped by joining a support group where members share common experiences and problems. See hemophilia - resources.
The probable outcome is good with proper treatment.
- Stroke or other neurological problems related to central nervous system bleeding
- Joint deformities may develop in severe cases due to recurrent bleeds
Calling your health care provider
Go to the emergency room or call the local emergency number (such as 911) if you have severe, unexplained bleeding.
This is an inherited disorder. There is no known prevention.
by Martin A. Harms, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.