Antiphospholipid syndrome (APS) is a serious autoimmune condition that causes the blood to clot too easily. It can lead to dangerous blood clots in the legs, lungs, and brain, as well as repeated pregnancy loss. In Canada, many people live with this condition without knowing it. Understanding the causes, symptoms, and treatment options can help you protect your health.
What Is Antiphospholipid Syndrome?
Antiphospholipid syndrome happens when your immune system mistakenly produces harmful proteins called antiphospholipid antibodies. These antibodies attack certain fats (phospholipids) found on the surface of your cells. As a result, your blood becomes much more likely to clot.
These clots can form in your veins or arteries anywhere in the body. In some cases, they can travel to vital organs and cause life-threatening emergencies. For pregnant women, APS also raises the risk of miscarriage and other serious complications.
For more background on autoimmune conditions, visit Health Canada’s official health information resource.
Types of Antiphospholipid Syndrome
Doctors generally divide antiphospholipid syndrome into two types: primary and secondary. Knowing which type you have helps guide your treatment plan.
Primary Antiphospholipid Syndrome
Primary APS occurs on its own, without any other autoimmune disease present. The exact cause of primary APS is not fully understood. However, researchers believe a combination of genetic and environmental factors plays a role.
Secondary Antiphospholipid Syndrome
Secondary APS develops alongside another autoimmune condition, most commonly lupus (systemic lupus erythematosus). In these cases, lupus or the other underlying disease is considered the root cause. Treating the underlying condition is an important part of managing secondary APS.
What Causes Antiphospholipid Syndrome?
The exact cause of antiphospholipid syndrome is still being studied. However, several factors are known to trigger or increase the production of antiphospholipid antibodies in the blood.
Infections
Certain infections can cause your immune system to produce antiphospholipid antibodies. These infections include syphilis, HIV, hepatitis C, and malaria. In most cases, the antibodies disappear once the infection is treated and resolved.
It is worth noting that antiphospholipid antibodies are found in about 2% of healthy people. These antibodies are often harmless and temporary. They do not always lead to clotting problems or a formal APS diagnosis.
Certain Medications
Some medications can trigger the formation of antiphospholipid antibodies. These include hydralazine (used to treat high blood pressure), quinidine (used to regulate heart rhythm), phenytoin (an anti-seizure drug), and amoxicillin (a common antibiotic). If you take any of these medications, do not stop them without speaking to your doctor first.
Genetic Predisposition
APS is not considered a directly inherited condition. However, research shows that close relatives of people with APS are more likely to carry antiphospholipid antibodies. This suggests that genetics may increase your overall risk. If a family member has APS, mention it to your family doctor.
Symptoms of Antiphospholipid Syndrome
The symptoms of antiphospholipid syndrome depend on where blood clots form in the body. Some people have no symptoms at all until a serious event occurs. Others notice warning signs that should never be ignored.
Common Symptoms
Blood clots in the legs (deep vein thrombosis): You may notice swelling, pain, or redness in your leg. These clots can break loose and travel to the lungs, causing a pulmonary embolism — a medical emergency.
Stroke: A clot blocking blood flow to the brain can cause a stroke, even in younger adults. Signs include sudden numbness, confusion, difficulty speaking, or vision changes.
Repeated pregnancy loss: Women with APS face a higher risk of miscarriage, premature birth, and preeclampsia (dangerously high blood pressure during pregnancy).
Less Common Symptoms
Neurological symptoms: Chronic headaches, migraines, seizures, and in severe cases, dementia can occur when clots block blood flow to parts of the brain.
Skin changes: A lacy, bluish-purple rash called livedo reticularis may appear on the skin, particularly on the arms and legs.
Cardiovascular problems: APS can affect heart valves and increase the risk of heart attack.
Unusual bleeding: In some cases, people with APS experience unexplained bleeding, which can seem contradictory to a clotting disorder.
For a comprehensive overview of blood clot symptoms, the Mayo Clinic’s guide to antiphospholipid syndrome is an excellent resource.
How Is Antiphospholipid Syndrome Diagnosed?
Diagnosing antiphospholipid syndrome requires both clinical evidence and blood tests. Your doctor needs to confirm that you have had a blood clot or pregnancy complication, and that antiphospholipid antibodies are present in your blood on at least two separate occasions, at least 12 weeks apart.
The key antibodies tested include anticardiolipin antibodies, beta-2 glycoprotein I antibodies, and lupus anticoagulant. A single positive result is not enough for a diagnosis. Your doctor will look at the full picture of your health history and test results together.
In Canada, these tests are available through your provincial health plan when ordered by your family doctor or a specialist. If your doctor suspects APS, they may refer you to a rheumatologist, haematologist, or internal medicine specialist.
Treatment Options for Antiphospholipid Syndrome
The main goal of treating antiphospholipid syndrome is to thin the blood and reduce the risk of dangerous clots forming. Your treatment plan will depend on your specific situation, including your symptoms, history of clotting, and whether you are pregnant.
Blood Thinners (Anticoagulants)
For people who have already had a blood clot or stroke, doctors typically recommend warfarin, a powerful blood-thinning medication. Warfarin requires regular blood monitoring to make sure the dose stays in the right range. Your doctor or anticoagulation clinic will guide you through this process.
Furthermore, low-dose aspirin is often recommended, especially for people who have not yet had a major clotting event. Aspirin helps reduce the stickiness of platelets in the blood.
Treatment During Pregnancy
Warfarin is not safe to use during pregnancy because it can cause birth defects. Therefore, pregnant women with APS are usually treated with a combination of low-dose aspirin and heparin injections. Heparin is a blood thinner that does not cross the placenta and is safe for the developing baby.
If you are pregnant or planning a pregnancy and have been diagnosed with APS, it is essential to work closely with both your obstetrician and your specialist. Close monitoring throughout your pregnancy gives you and your baby the best chance of a healthy outcome.
Managing Underlying Conditions
For people with secondary APS, treating the underlying autoimmune condition — such as lupus — is also a key part of the overall treatment plan. In addition, managing other cardiovascular risk factors like high blood pressure, high cholesterol, and smoking cessation all help reduce your overall clotting risk.
Learn more about blood clot prevention and cardiovascular health from Healthline’s in-depth article on antiphospholipid syndrome.
When to See a Doctor
You should see your family doctor as soon as possible if you experience unexplained leg swelling or pain, sudden chest pain or difficulty breathing, signs of a stroke, or repeated miscarriages. These symptoms may point to antiphospholipid syndrome or another serious condition that needs prompt attention.
If you cannot get a timely appointment with your family doctor, a walk-in clinic can assess your symptoms and arrange urgent referrals if needed. In an emergency — such as signs of a stroke or pulmonary embolism — call 911 or go to your nearest emergency department immediately.
If you have a family history of APS or an autoimmune disease like lupus, bring it up at your next regular check-up. Early detection through blood tests covered by your provincial health plan can make a real difference in managing this condition effectively.
Always consult your family doctor or a qualified healthcare professional before starting, stopping, or changing any medication or treatment plan.
Frequently Asked Questions About Antiphospholipid Syndrome
What is antiphospholipid syndrome in simple terms?
Antiphospholipid syndrome is an autoimmune disorder where your immune system produces antibodies that make your blood clot too easily. These clots can form in veins or arteries throughout the body and can cause strokes, pulmonary embolisms, and pregnancy complications. It is a manageable condition with the right medical treatment and monitoring.
Can you live a normal life with antiphospholipid syndrome?
Yes, many people with antiphospholipid syndrome live full, active lives with proper treatment and regular medical follow-up. Blood-thinning medications like warfarin or aspirin significantly reduce the risk of dangerous clots. Working closely with your doctor and following your treatment plan is key to staying healthy.
Is antiphospholipid syndrome the same as lupus?
No, antiphospholipid syndrome and lupus are not the same condition, but they are closely linked. APS can occur on its own (primary APS) or develop in people who already have lupus (secondary APS). About 30 to 40 percent of people with lupus also have antiphospholipid antibodies.
What triggers antiphospholipid syndrome flare-ups?
Certain infections, prolonged periods of inactivity, surgery, pregnancy, and stopping blood-thinning medications suddenly can all trigger complications in people with antiphospholipid syndrome. Smoking and uncontrolled high blood pressure also increase the risk of clotting events. Talk to your doctor about how to manage and reduce your personal risk factors.
How is antiphospholipid syndrome diagnosed in Canada?
In Canada, antiphospholipid syndrome is diagnosed through blood tests ordered by your family doctor or a specialist, which look for specific antiphospholipid antibodies. To confirm a diagnosis, the antibodies must be detected on at least two separate occasions, 12 weeks apart. These tests are typically covered by your provincial health plan when medically necessary.
Can antiphospholipid syndrome cause a miscarriage?
Yes, antiphospholipid syndrome is one of the leading treatable causes of recurrent miscarriage. The antiphospholipid antibodies can interfere with blood flow to the placenta, increasing the risk of pregnancy loss, preeclampsia, and premature birth. With proper treatment — usually low-dose aspirin and heparin — many women with APS go on to have successful pregnancies.
Key Takeaways
Antiphospholipid syndrome is an autoimmune condition that causes the blood to clot too easily, leading to potentially serious complications.
APS can be primary (on its own) or secondary (linked to another autoimmune disease like lupus).
Common triggers include certain infections, specific medications, and genetic predisposition.
Symptoms range from leg clots and stroke to recurrent miscarriage and skin changes.
Treatment focuses on blood-thinning medications such as warfarin, aspirin, or heparin during pregnancy.
In Canada, diagnosis and treatment are accessible through your provincial health plan via your family doctor or specialist.
If you notice warning signs, see your family doctor or visit a walk-in clinic promptly — and call 911 in an emergency.
Always speak with a qualified healthcare professional before making any changes to your treatment.
