Antiphospholipid syndrome (APS), also known as Hughes syndrome, is a disorder of the immune system that causes an increased risk of blood clots and miscarriages.
People with APS are at risk of developing conditions such as deep vein thrombosis (a blood clot that usually develops in the leg) and arterial thrombosis (a clot in an artery), which can cause a stroke or heart attack.
Pregnant women with the syndrome have an increased risk of having a miscarriage, although the exact reasons for this are uncertain.
APS can affect people of all ages, including children and babies. However, it usually affects adults aged 18–40, and affects five times as many women as men.
There is currently no cure for APS. However, if it is correctly diagnosed, the risk of developing blood clots can be greatly reduced.
Diagnosing APS
It is possible for APS to be misdiagnosed because its symptoms can be similar to those of multiple sclerosis (a common condition that affects the central nervous system). Symptoms of both conditions include:
- balance and mobility problems
- vision problems, such as double vision
- speech and memory problems
- a tingling sensation or pins and needles in your arms or legs
- fatigue (extreme tiredness)
However, symptoms indicating that a person has APS rather than multiple sclerosis include:
Read more about the symptoms of APS.
Blood tests designed to help identify the antibodies (proteins) responsible for APS are essential in diagnosing the syndrome. Three main types of antibodies can be measured:
- anti-cardiolipin
- anti-B2 GPI
- the lupus anticoagulant
Read more about how APS is diagnosed.
What causes APS?
APS is an autoimmune condition. This means the immune system, which usually protects the body from infection and illness, attacks healthy tissue.
The immune system produces abnormal antibodies called antiphospholipid antibodies. They bind to proteins and fats in the blood, including an important type of fat called phospholipid.
Phospholipids and proteins are thought to help keep the blood at the right consistency. If the fats and proteins are bound by antibodies, the blood becomes more likely to clot.
It is not known what causes the immune system to produce abnormal antibodies, but like other autoimmune conditions, both genetic and environmental factors are thought to play a part.
Read more about the causes of APS.
Treating APS
As there is no cure for APS, treatment aims to reduce the risk of developing further blood clots.
Anticoagulant medicines, such as warfarin, or an antiplatelet, such as aspirin, are usually prescribed. These reduce the likelihood of blood clots forming when they are not needed but still allow clots to form when you cut yourself.
Additional treatment is also available for pregnant women with APS to help improve their chances of having a successful pregnancy.
Read more about how APS is treated.
Despite serious and potentially life-threatening consequences, most people respond well to anticoagulants and can lead normal, healthy lives. Treatment can also help improve the outcomes of pregnancy in 75–80% of women.
Outlook
Despite having serious and potentially life-threatening consequences, most people respond well to anticoagulants and the outlook is generally good.
Treatment with anticoagulants can also help improve the outcomes of pregnancy and an estimated 75-80% of women will have a successful pregnancy after being treated.
A small number of people with APS continue to experience blood clots despite having extensive treatment.
