Filed under: Boomer's Health
Factor V Leiden (FAK-tur five LIDE-n) is a mutation of one of the clotting factors in the blood called factor V. This mutation can increase your chance of developing abnormal blood clots (thrombophilia), usually in your veins.
Most people with factor V Leiden never develop abnormal clots. However, some people with factor V Leiden develop clots that lead to long-term health problems or become life-threatening.
Both men and women can have factor V Leiden, but women may have an increased tendency to develop blood clots during pregnancy or when taking the hormone estrogen.
If you have factor V Leiden and have developed blood clots, medications can lessen your risk of developing additional blood clots and help you avoid potentially serious complications.
Most people who have factor V Leiden never develop signs or symptoms. However, the first indication that you have the disorder may be the development of a blood clot (thrombosis).
Some clots do no damage and disappear on their own. Others can be life-threatening. Symptoms of a blood clot depend on where it forms and whether and where it travels.
A clot developing in a deep vein
This is known as deep vein thrombosis (DVT). A DVT may not cause any symptoms. If signs and symptoms do occur, they commonly affect your legs, including your ankles and feet, and may include:
A clot that forms closer to the surface of your skin
This is referred to as superficial venous thrombosis, phlebitis or thrombophlebitis. Signs and symptoms usually include:
A clot that travels to your lungs
Known as a pulmonary embolism, this occurs when a deep vein clot breaks free and travels through the right side of your heart to your lung, where it blocks blood flow. Symptoms may include:
When to see a doctor
Seek medical attention immediately if you:
See a doctor if you:
A blood clot (thrombus) normally forms to stop the bleeding when an artery or vein is damaged, such as when you experience a cut. Clots form as a result of chemical reactions between specialized blood cells (platelets) and proteins in your blood (clotting factors). Substances in the blood known as anti-clotting factors control excessive formation of blood clots.
Normally, factor V is a clotting protein. But, people with factor V Leiden have a genetic mutation that causes the factor V protein to respond more slowly to being deactivated by the anti-clotting factors.
In the normal clotting process, anti-clotting proteins combine to help break up factor V to keep it from being reused and forming clots when clotting isn't needed. However, the factor V Leiden mutation keeps the anti-clotting proteins from breaking down factor V, which keeps it in the blood longer and increases the chance of clotting.
If you have factor V Leiden, you either inherited one copy of the defective gene (heterozygous), which slightly increases your risk of developing blood clots, or more rarely you inherited two copies, one from each parent (homozygous), which significantly increases your risk of developing blood clots.
A family history of factor V Leiden increases your risk of inheriting the disorder. The disorder is most common in people who are white and of European descent.
Risk factors that can increase your risks of developing complications, such as a DVT, include:
Factor V Leiden can be associated with a variety of serious and potentially serious clotting complications, including:
Your doctor may suspect you have factor V Leiden if:
Your doctor may refer you to a specialist in genetic disorders (geneticist) or a specialist in blood disorders (hematologist) for testing to determine whether the cause of your blood clots is genetic, and specifically, whether you have the factor V Leiden mutation. It's a good idea to be well prepared for your appointment. Here's some information to help you get ready, and what to expect from your doctor.
What you can do
Preparing a list of questions can help you make sure that you cover everything that's important to you. For factor V Leiden, some basic questions to ask your doctor include:
If your doctor recommends genetic testing, some questions you might want to ask the genetic specialist include:
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask additional questions anytime you don't understand something.
Your doctor will likely suspect factor V Leiden if you've had one or more episodes of thrombosis or pregnancy loss or if you have a strong family history of thrombotic disease. Your doctor can confirm that you have factor V Leiden with a blood test. Two types of tests can be done:
Genetic test. A genetic test either is done as a secondary test to confirm the results of the APC resistance test or is done alone to determine whether you have a factor V gene mutation. If you're already taking medication for thrombosis, you're likely to have only the genetic test because blood-thinning (anticoagulant) medications interfere with the activated protein C resistance test. The genetic test also can determine whether you've inherited one or two copies of the gene mutation.
Testing babies prenatally or soon after birth isn't recommended, nor is screening of children who don't have symptoms of clotting problems. Because blood clots are so unusual, even in children with factor V Leiden, it's recommended that you wait until your child is an adult who can fully understand the risks and benefits associated with genetic testing.
Doctors generally use blood-thinning (anticoagulant) medications, such as warfarin (Coumadin), heparin or low molecular weight heparin to treat people who develop blood clots.
If genetic tests have confirmed that you have a factor V mutation, but you haven't had any blood clots, then your doctor probably won't routinely prescribe blood thinners unless you're in a high-risk situation, such as being hospitalized for surgery or other medical reasons. In that case, you may receive preventive doses of blood thinners during your hospital stay.
If you have a blood clot, standard initial treatment involves a combination of heparin and warfarin. Your doctor will discontinue the heparin after the initial treatment and continue the warfarin. How long you need to take medication will depend on the circumstances of your thrombosis.
If you're taking anticoagulant medication that can be monitored, your doctor will monitor your dose with blood tests to be sure your blood is capable of clotting enough to stop bleeding if you bruise or cut yourself.
Most women with factor V Leiden have normal pregnancies. However, the risk of blood clots during pregnancy is higher. Pregnant women with factor V Leiden need close medical supervision throughout their pregnancies. There's currently no evidence that preventive treatment with blood-thinning medications would be effective enough to outweigh the potential risks of using these drugs during pregnancy or delivery.
When your baby is born, routine testing of newborns isn't currently recommended because blood clots are rare in children and teens, and chances are good that your child may never have any signs or symptoms related to factor V Leiden.
If you have factor V Leiden, avoiding certain situations might help to reduce your risk of developing blood clots. These include:
One situation you don't have to avoid if you have factor V Leiden is donating blood. People with factor V Leiden can usually donate blood if interested in doing so. However, if you're taking blood-thinning medications, you can't donate blood until those medications are fully out of your system. If you've taken blood thinners, check with your doctor before donating blood.
If your factor V Leiden requires you to take anticoagulant medication, here are some steps that might help prevent injury and avoid excessive bleeding. Consider these suggestions: