Antiphospholipid Syndrome (APS)
WHAT ARE PHOSPHOLIPIDS AND ANTIBODIES TO THEM
Phospholipids are present in cell membranes, including blood cells and endothelial cells lining blood vessels. In some people, the immune system produces antibodies to proteins that are bound to phospholipids. The presence of these antiphospholipid antibodies can increase the risk of developing blood clots in veins or arteries, as well as raise the risk of miscarriage or stillbirth in pregnant women. However, some individuals have these antibodies without developing clots or pregnancy complications.
People who have these antibodies and develop clots or pregnancy-related complications are said to have a condition called antiphospholipid syndrome (APS).
APS is an autoimmune disorder, which means it occurs when the body’s immune system mistakenly attacks healthy tissues and organs.
APS is more common in patients with other autoimmune or rheumatologic diseases, especially systemic lupus erythematosus (SLE). APS is called primary when it occurs on its own.
SYMPTOMS OF ANTIPHOSPHOLIPID SYNDROME
The symptoms of APS are primarily related to problems with blood clotting, miscarriage, or stillbirth.
Thrombosis (blood clot): The presence of antiphospholipid antibodies increases the risk of clot formation in a vein or artery. Without treatment, patients often develop recurrent clots. Blood flow to vital organs and their function can be impaired depending on the clot’s location.
Brain: Arterial clots can disrupt blood supply to the brain, causing anything from transient reversible neurological symptoms to a stroke with permanent brain damage.
Kidneys: Blood flow disruption can range from mild kidney dysfunction to kidney failure.
Deep vein thrombosis (DVT): Clots in large veins (usually the legs, sometimes arms) cause pain and swelling. Such clots may break loose, travel through the heart, and block blood flow in the lungs, causing pulmonary embolism (PE). Symptoms may include chest pain, shortness of breath, or coughing up blood. Large clots can cause fainting or even death.
Miscarriage / Stillbirth: In women with APS, antibodies may increase the risk of pregnancy loss.
Thrombocytopenia (low platelets): In some APS patients, the platelet count drops. Platelets are essential for normal clotting. When platelets fall significantly (below 30,000), there is risk of bleeding (nose, gums, skin petechiae, GI tract, uterus). However, in APS, low platelets can paradoxically be associated more with increased clotting risk than bleeding.
Other manifestations: anemia, heart valve damage, skin rashes or ulcers, and memory problems.
DIAGNOSIS OF APS
Diagnosis is based on clinical history + laboratory data. Requirements:
At least one of the following clinical events:
Blood clot (venous or arterial),
One or more miscarriages after 10 weeks of pregnancy,
Three or more miscarriages before 10 weeks,
One or more premature births before 34 weeks due to eclampsia.
Detection of antiphospholipid antibodies in blood tests at least twice, 12 weeks apart. These include:
Lupus anticoagulant (LA),
Anticardiolipin antibodies,
Anti-beta-2 glycoprotein I antibodies.
PREVENTION AND TREATMENT
Anticoagulants: Medications that prevent existing clots from growing and reduce new clot formation (sometimes mistakenly called “blood thinners”).
Patients with APS and acute clots are usually treated with heparin or low molecular weight heparin (LMWH) such as enoxaparin, dalteparin, etc. These can be given in hospital IV, or subcutaneously at home by the patient/family/nurse.
Often combined with warfarin, an oral anticoagulant used for long-term prevention. Heparin is stopped once warfarin levels are stable.
Warfarin monitoring: Careful dose monitoring is required. The effect is measured by prothrombin time (PT), expressed as INR (international normalized ratio).
Target INR is usually 2–3.
INR below range = risk of clotting.
INR above range = risk of bleeding.
Antiplatelet agents: Aspirin may sometimes be recommended. It inhibits platelet aggregation. It is sometimes used in addition to warfarin, but not as a replacement in patients with serious/recurrent thrombosis.
Perioperative management: Anticoagulation/antiplatelet therapy often needs adjustment before, during, and after surgery to minimize both clotting and bleeding risks.
Warfarin is usually stopped a few days before surgery.
Temporary heparin “bridging” may be used depending on risk factors.
Warfarin is typically restarted within 12 hours after surgery.
Patients must always coordinate with their prescribing physician to determine the safest regimen around surgical procedures.