Antiphospholipid syndrome

Antiphospholipid syndrome (APS, also known as Hughes syndrome) is an immune disorder that makes blood clot far too readily inside the vessels. Clots form where they have no business being: in the leg veins, in the arteries of the brain, in the vessels of the placenta. This is not an inherited clotting fault — the culprits are the person's own antibodies. The syndrome is found mainly in women, usually between the ages of twenty and fifty, and almost always after a first thrombosis or after several pregnancy losses. There is no way to remove the antibodies, but treatment lowers the risk of clots a great deal.

What these antibodies actually do

An antibody normally recognises something foreign: a bacterium, a virus. In APS it latches onto something of its own — proteins that sit on the fatty molecules (phospholipids) in the membranes of blood cells and vessel walls. The main target carries a long name: beta-2 glycoprotein I. The balance that keeps blood flowing breaks down, the lining of the vessels and the platelets switch into alarm mode, and the body's natural brakes on clotting lose their grip. Blood does not turn sticky everywhere at once, but patch by patch, which is why nobody can predict where an APS clot will appear.

Where the antibodies come from is not fully known. A hereditary predisposition is likely, together with some trigger — an infection, certain medicines. Systemic lupus erythematosus is a story of its own: in some people APS travels alongside lupus, so once the syndrome is confirmed a doctor will look in that direction too.

How the syndrome announces itself

APS has no symptoms of its own. It speaks through clots and through everything they cause.

• Veins. Most often deep vein thrombosis in a leg: swelling, a tight bursting pain in the calf, skin warmer and darker than usual. A clot that breaks loose travels to the lungs.
• Arteries. Stroke, a transient stroke-like episode, heart attack, less often a blocked vessel in the eye. A stroke in someone under fifty with no high blood pressure and no raised cholesterol is especially suspicious.
• Unusual sites. Veins inside the skull, in the liver, the kidney, the bowel. A clot in an unusual place is on its own a reason to test for APS.
• Skin. A stubborn bluish-purple net-like pattern on the thighs and forearms, clearer in the cold; sometimes ulcers on the lower legs that refuse to heal.
• Platelets. Their count is sometimes low, which is confusing: the blood test hints at bleeding while the tendency to clot has not gone anywhere.
• And more. Persistent headaches, trouble with memory, fatigue, thickened heart valves seen on a scan.

Pregnancy with APS

Tiny clots in the placental vessels stop the placenta from feeding the baby properly, so untreated APS brings a set of pregnancy problems of its own: repeated miscarriages in the early weeks, loss later in pregnancy, pre-eclampsia, poor growth of the baby, premature birth.

This is in fact how APS is often found. Three early losses in a row, or a single unexplained loss after the tenth week, are a reason to be tested rather than to put everything down to bad luck. And this is where treatment shows its worth most plainly: with the right regimen most pregnancies end with a baby. Planning has to start early, because some of the medicines are dangerous for the baby and the regimen is changed before conception, not after.

How the diagnosis is confirmed

The diagnosis rests on two halves: an event — a clot or a pregnancy loss — and a blood test that stays positive. Three things are looked for: lupus anticoagulant, anticardiolipin antibodies and antibodies to beta-2 glycoprotein I. Blood is taken twice, at least twelve weeks apart, because after an infection or while taking certain drugs these antibodies show up briefly and then vanish on their own. A diagnosis made on a single sample is often wrong and drags years of unnecessary treatment behind it.

Two things are worth knowing in advance. In the test tube the clotting time may come back prolonged, as it does in people who bleed easily, even though real life works the other way round. And the lupus anticoagulant test is distorted if the person is already taking an anticoagulant, so blood is best drawn before treatment starts — and if that was not possible, the laboratory should be told.

Why treatment is for the long haul

There is a single aim: to stop the next clot forming. That is why the medicines are taken continuously rather than in courses. If a clot has already happened, an anticoagulant from the vitamin K antagonist group is prescribed and its effect is checked with regular blood tests. If antibodies have been found but there has never been a clot or a pregnancy loss, low-dose aspirin or plain monitoring is often enough — the choice depends on which antibodies turned up and in what amount. In the first days after a clot, injected heparins are used, and when APS comes with lupus, hydroxychloroquine is added.

The newer tablet anticoagulants, widely used for other kinds of thrombosis, deserve a separate word. In APS they performed worse: clots came back more often, particularly in people with arterial events and with all three tests positive, so switching for the sake of convenience is not a good trade. The most dangerous move of all is stopping treatment on your own — anticoagulant withdrawal is a known trigger for severe flares. Any pause before surgery is planned together with a doctor.

Catastrophic APS

This is a rare form, fewer than one case in a hundred people with the syndrome, and the worst thing the disease can do. Clots appear all at once in a multitude of small vessels, and within days several organs fail. The trigger is often an infection, an operation, an injury or, precisely, an anticoagulant that was stopped.

What it looks like depends on which organs are hit: mounting breathlessness, abdominal pain, darkening fingertips, swelling, blood in the urine or a sharp drop in how much is passed, confusion, seizures. It is treated only in intensive care, and even with everything available the risk to life is very high. There is no room for waiting: if someone with APS is visibly getting worse, the clock runs in hours.

When to call for emergency help

Call the emergency services straight away (112 across Europe) if there is:

• a drooping face, weakness in an arm or leg on one side, slurred or muddled speech — even if it all passes within minutes;
• sudden breathlessness, chest pain on breathing in, coughing up blood, a racing heartbeat;
• crushing chest pain spreading to the arm, neck or jaw;
• sudden loss of vision in one eye;
• severe pain and fast-growing swelling in one leg.

The second set of warnings points the other way — that the blood has been thinned too far: blood in the urine, black stools, blood in sputum or vomit, a nosebleed lasting more than ten minutes, large bruises with no injury behind them. Here you ring your doctor the same day, and for heavy bleeding you call for emergency help.

What is in your hands

• do not smoke: the risk from tobacco and the risk from the antibodies add up;
• discuss contraception — combined oestrogen preparations and menopausal hormone therapy usually do not fit here, but other options exist;
• on long journeys get up, work your feet, drink water, and before a long trip ask your doctor whether extra protection is needed;
• keep blood pressure, weight and cholesterol under control, because those risks stack on top of the antibodies;
• tell every doctor, dentists included, about the diagnosis and the medicine, and never start new drugs or supplements on your own — many of them change how anticoagulants work.

Online consultation

In an online consultation a doctor goes through your history — whether there have been clots, how pregnancies went, what the blood tests showed — explains which tests make sense and why they will have to be repeated, and points you to the right specialist for a face-to-face visit. It is also a convenient place to ask the things there is rarely time for: how to prepare for an operation, what to do about a missed dose, how to plan a pregnancy or a long journey.

This material is for information only and does not replace medical advice.