Antiphospholipid syndrome: Symptoms, treatment, and diagnosis

Antiphospholipid syndrome is an immune disorder in which abnormal antibodies are linked to abnormal blood clots in veins and arteries. It mostly affects the legs, but clots may also form in the kidneys, lungs, and other organs.

It may lead to complications in pregnancy, such as recurring pregnancy loss and preterm births.

Antiphospholipid syndrome (APS) is also known as Antiphospholipid Antibody Syndrome, Hughes syndrome, or sticky blood.

The abnormal antibodies attack fats that contain phosphorous, known as phospholipids. Heart valve abnormalities are common in people with APS, and up to one in three cases of stroke under the age of 50 years may be due to it.

In the legs, APS can lead to deep vein thrombosis (DVT). If a clot develops in the brain, there is a serious risk of stroke.

There is no cure for APS, but current treatments can significantly reduce the risk of developing blood clots.

Most people with APS who receive treatment can lead normal, healthy lives, but, rarely, a person with the syndrome will continue to develop clots.

According to the APS Foundation of America, between 1 and 5 percent of people in the United States are thought to have APS. It is responsible for 15 to 20 percent of all cases of DVT and pulmonary embolism, or blood clots on the lung. It affects women three to five more often than men.


[blood clotting]
Antiphospholipid syndrome affects blood consistency.

Signs and symptoms of antiphospholipid syndrome depend mainly on where the clots travel to, and where they form.

A clot or embolus, which is a traveling clot, can result in:

DVT: A clot forms in one of the large veins, usually in the arm or leg, and it partially or completely blocks circulation. If a DVT blood clot moves into the lungs, a life-threatening condition known as a pulmonary embolism (PE) can result.

Pulmonary embolism (PE): An embolus, or traveling clot, appears in one part of the body, circulates throughout the body, and then blocks blood flowing through a vessel in another part of the body. In PE, an embolus blocks an artery that feeds the lungs.

Complications of pregnancy: These include recurring miscarriages, preterm delivery, and preeclampsia, or high blood pressure during pregnancy.

Ischemic stroke: A blood clot interrupts blood flow to a part of the brain, cutting off the supply of oxygen and glucose. Brain cell death and brain damage can results. Around 75 percent of all stroke cases are ischemic.

Less common signs and symptoms include:

headaches or migraines

dementia and seizures, if a clot blocks blood flow to parts of the brain

livedo reticularis, a lace-like purplish rash on the knees and wrists

Around 30 percent of people with APS have heart valve abnormalities. In many cases, the mitral valve thickens, or develops extra mass, causing blood to leak back into one of the heart’s chambers. Some patients may have problems with the aortic valve.

Levels of platelets can drop. Platelets are the blood cells that are needed for normal clotting. This can lead to episodes of bleeding, for examples nosebleeds, or bleeding gums. Some people may experience bleeding into the skin, causing small red spots to appear.

In very rare cases, a person may develop:

chorea, an involuntary jerking of the body and limbs

memory problems

mental health problems, such as depression or psychosis

hearing loss

Symptoms tend to appear between the ages of 20 and 50 years, but sometimes they develop during childhood.

Catastrophic antiphospholipid syndrome

Catastrophic antiphospholipid syndrome (CAPS) is a type of “thrombotic storm,” in which multiple clots suddenly form. It affects a small minority of patients with APS, progressively damaging several organs.

Blood clots abruptly develop all over the body, resulting in multiple organ failure. Why it happens is unclear.

Symptoms vary, depending on which organs are affected, but they include:

abdominal pain


edema, or swelling, in the ankles, feet, or hands

fits, or seizures

progressive breathlessness




Symptoms tend to appear suddenly and get worse rapidly.

CAPS is a medical emergency and the patient will need intensive care as soon as possible, so that the body’s functions can be maintained while high-dose anticoagulants are administered.

Research suggests that around 46 percent of patients with catastrophic antiphospholipid syndrome do not survive the initial event, and there is a risk of a repeat event at some time, even with medical care.

Deep vein thrombosis and pulmonary embolismDeep vein thrombosis and pulmonary embolism
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A doctor will usually prescribe medication to thin the blood, to reduce the chance of clotting. The patient will normally need this medication for the rest of their life.

Possible combinations include aspirin with warfarin, or Coumadin, or possibly heparin. If warfarin does not work, the dose may be increased or heparin may be added.

The clotting action of anticoagulants can sometimes lead to a hemorrhage, or excessive bleeding.

Patients should seek medical help at once if they experience:

blood in feces, urine, or vomit

coughing up blood

nosebleeds lasting longer than 10 minutes

severe bruising

Patients who experience thrombosis will normally need to take heparin and warfarin. When the thrombosis clears, they will continue with warfarin.

Treatment in pregnancy

A woman with a diagnosis with APS should plan for pregnancy from before conception. Treatment will start at the beginning of pregnancy and finish after delivery.

[blood test]
It is important to monitor the blood, especially during pregnancy.

In an unplanned pregnancy, the effectiveness of treatment may be reduced as it will not begin until several weeks after conception.

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