Antiphospholipid Antibody Syndrome (APS)

When the body is functioning normally, antibodies are proteins in the blood that fight off infection. Sometimes, however, conditions can cause these antibodies to fight against normal parts of the body instead.

Antiphospholipid antibody syndrome (APS) occurs when these antibodies attack the body's phospholipids, which are an important part of the blood clotting process. Damage to these cells can result in blood clots forming in the blood vessels of the body when they should not.

Any condition that causes clots that limit or block blood flow through the brain can result in serious complications such as a stroke.

Symptoms

Symptoms associated with APS vary depending on the how serious the conditions is, and where abnormal blood clots form.

If a blood clot forms in the arms or legs, it may travel to the lungs (pulmonary embolism), brain (stroke) or heart (heart attack). General symptoms associated with abnormal blood clotting include:

  • Chest pain
  • Shortness of breath
  • Repeated headaches
  • Changes in speech
  • Redness or swelling in the limbs
  • Tissue damage due to limited or blocked blood flow
  • Nausea

Women with APS who are pregnant may notice the following symptoms:

  • Repeated miscarriages or stillbirths
  • Premature delivery
  • Preeclampsia

Patients who have experienced a stroke due to APS may display "classic" stroke symptoms including:

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
  • Sudden confusion
  • Sudden trouble speaking
  • Sudden trouble seeing in one or both eyes
  • Sudden trouble walking
  • Sudden dizziness, loss of balance or coordination
  • Sudden, severe headache with no known cause

 

Causes and Risk Factors

When the body is functioning normally, antibodies are proteins in the blood that fight off infection. Sometimes, however, conditions can cause these antibodies to fight against normal parts of the body instead. Antiphospholipid antibody syndrome (APS) occurs when these antibodies attack the body’s phospholipids, which are an important part of the blood clotting process.

Risk factors associated with APS include:

Diagnosis

Diagnosis of APS usually begins with a physical exam and a review of the patient's medical history and symptoms. A positive diagnosis of the condition is based on the patient's symptoms as well as the findings of blood tests. Other diagnostic tools may be used to better understand the patient's condition. Note that the blood tests may need to be repeated more than once to secure a diagnosis.

A blood test is the only way to positively diagnose APS. The blood sample will be examined under a microscope to determine if one of the following three antibodies is present:

  • Lupus anticoagulant
  • Anti-cardiolipin
  • Beta-2 glycoprotein I

Other diagnostic tools may include magnetic resonance imaging (MRI) and computed tomography (CT) angiography, which can be used to observe the condition and the area affected by disorder. Other tests look exclusively at the blood vessels, such as an angiogram.

A transcranial Doppler ultrasound may be used to measure the blood that is flowing through the arteries at the base of the brain.

Treatments

Treatment of APS usually includes blood-thinning drugs, such as aspirin or warfarin, to prevent the blood from clotting. Other treatments may be prescribed and will depend on the location of the blood clot and the severity of the condition.