Key Points

• Antiphospholipid antibody syndrome (APS) is an autoimmune disorder. Autoimmune disorders occur when the immune system makes antibodies that attack and damage the body’s tissues or cells by mistake.
• In APS, the body makes antibodies that attack phospholipids—a type of fat. This can cause blood clots to form in the body’s arteries and veins. Blood clots can limit or block blood flow and damage the body’s organs.
• Some people have the APS antibodies, but don’t ever have signs or symptoms of the disorder. The presence of APS antibodies, by itself, doesn’t mean that you have APS. To be diagnosed with APS, you must have APS antibodies and a history of health problems related to the disorder.
• APS can lead to a number of health problems, such as stroke, heart attack, kidney damage, deep vein thrombosis, or pulmonary embolism. In women, APS raises the risk for miscarriages, stillbirths, and other pregnancy-related problems. In some cases, APS can cause death.
• APS can affect people of any age. The disorder is more common in women and people who have other autoimmune or rheumatic disorders, such as lupus.
• The signs and symptoms of APS are related to abnormal blood clotting. The outcome of the blood clot depends on its size and location.
• Common signs and symptoms of blood clots include chest pain and shortness of breath; pain, redness, warmth, and swelling in the limbs; ongoing headaches; speech changes; upper body discomfort in the arms, back, neck, and jaw; and nausea (feeling sick to your stomach).
• Your doctor will diagnose APS based on your medical history and the results from blood tests. Blood tests can confirm if you have any APS antibodies.
• APS has no cure. However, some medicines can help prevent complications. Anticoagulants, or "blood thinners," are used to stop blood clots from forming. These medicines also keep existing clots from getting larger.
• The most common side effect of blood thinners is bleeding. This happens if the medicine thins your blood too much. Bleeding can occur inside your body (internal bleeding) or on the skin. Talk to your doctor about the warning signs of internal bleeding and when to seek emergency care.
• If you have APS, it’s important to take all of your medicines as your doctor prescribes, get ongoing medical care, and talk to your doctor about healthy lifestyle changes and other concerns.
• Research is ongoing for new ways to treat APS.