Antithrombin Deficiency

Overview

Antithrombin deficiency (or antithrombin III deficiency) is a blood clotting disorder that makes you more likely to get abnormal blood clots. People with this problem are at a high risk for deep vein thrombosis (a blood clot in any deep vein of the body) and pulmonary embolism (a clot that ends up in your lungs).

Antithrombin helps keep your blood from clotting excessively. When your antithrombin isn’t working right, clotting can keep going without antithrombin stopping it. When you don’t have enough antithrombin, it’s like starting to fill a bathtub with water and then walking away. Someone needs to be there to turn the water off to keep the bathtub from overflowing, just like the antithrombin needs to stop the clotting before it goes on too long.

Symptoms

Different people with antithrombin deficiency may have different symptoms, but your first blood clot usually happens before age 40. The most common symptoms include:

1.Deep vein thrombosis (DVT).

2.Pulmonary embolism.

Although it’s not as common, clots can also happen in veins in your brain and abdomen.

Treated

After you’ve had a clot, your provider may want you to take warfarin (Coumadin®), a blood thinner, for a few months or possibly long-term. People who have antithrombin deficiency but haven’t had a blood clot don’t need to take blood thinners.

Because 3% to 50% of pregnant people with an antithrombin deficiency get blood clots, your provider may decide to give you heparin injections during pregnancy to prevent blood clots during that special time.

What causes antithrombin deficiency?

People who have a mutation on their SERPINC1 gene have antithrombin deficiency. You can inherit this mutation from one of your parents, but those who are born with this mutation won’t necessarily get a blood clot. There is a 50% chance of passing the mutation on to each child you have, regardless of their gender. Unfortunately, babies who inherit antithrombin deficiency from both parents usually don’t survive.

How is antithrombin deficiency diagnosed?

To make a diagnosis, your provider will want:

1.Physical exam.

2.Medical history.

3.A blood test that specifically measures antithrombin levels.

How do I take care of myself?

Be sure to keep all of your appointments with your provider. Because taking warfarin or heparin can cause bleeding, your provider will want to make sure you’re getting the right amount of medicine. A prothrombin time or PT test can tell your provider if your warfarin dose is correct. Your provider can adjust your warfarin dose so you don’t get a bad clot, but you don’t bleed too much either.

How can I reduce my risk?

If you have antithrombin deficiency, you can reduce your risk of blood clots in a few ways:

1.Avoid taking birth control pills.

2.Avoid taking hormone therapy.

3.Don’t be inactive for long periods of time.

4.Don’t smoke or use tobacco products.

5.Stay at a healthy weight.

Other things that put you at risk for blood clots include trauma, surgery, pregnancy, childbirth and aging. If you need surgery or are giving birth, your provider can give you a special antithrombin concentrate through an IV in your arm.

What can I expect if I have antithrombin deficiency?

One of every two to three people with this problem may develop blood clots in adulthood. Your risk of clots is higher if you have surgery or don’t move your body enough. As you get older, that increases your risk, too. If you have antithrombin deficiency, unusual blood clots can develop during pregnancy or after your baby is born.

How long does antithrombin deficiency last?

Since hereditary antithrombin deficiency is something you’re born with, it’s part of your genetic makeup for life.

How do I take care of myself?

You should know the warning signs of deep vein thrombosis and a pulmonary embolism so you can get help quickly. If you’re on warfarin or other blood thinners, which can carry a risk of bleeding, be careful when using sharp objects. You may also want to avoid sports that can put you at risk for injury.

Can you test for antithrombin deficiency?

Antithrombin testing is primarily ordered, along with other tests for excessive clotting disorders, to investigate the cause of recurrent blood clot formation (thrombosis). Testing evaluates the activity (function) and the amount (quantity) of antithrombin and helps identify antithrombin deficiency.

What are the first signs of blood clotting?

Symptoms of a blood clot include:

1.throbbing or cramping pain, swelling, redness and warmth in a leg or arm.

2.sudden breathlessness, sharp chest pain (may be worse when you breathe in) and a cough or coughing up blood.

Where does your chest hurt with a blood clot?

Main symptoms of a pulmonary embolism include chest pain that may be any of the following: Under the breastbone or on one side. Sharp or stabbing. Burning, aching, or a dull, heavy sensation.