Catastrophic antiphospholipid syndrome (CAPS) is a rare and potentially life-threatening complication of antiphospholipid syndrome (APS) that needs emergency treatment. It occurs in less than 1% of people with APS.

In people who develop CAPS, blood clots suddenly form throughout the body, resulting in multiple organ failure.

It's not clear what causes this, but 1 case in 5 occurs after an infection, trauma or surgery.

The initial symptoms can be wide-ranging, depending on which organs are involved.

Symptoms may include:

• loss of blood supply to the tips of your fingers or toes, causing them to go dark blue or black, but this may be hard to see on people with black or brown skin
• swollen ankles, feet or hands
• increasing shortness of breath
• tummy (abdominal) pain
• blood in your urine
• confusion
• fits (seizures)
• coma

The symptoms usually develop suddenly and rapidly get worse.

Dial 999 and ask for an ambulance immediately if you or someone you know has APS that suddenly gets worse.

Immediate admission to an intensive care unit (ICU) is required for people with CAPS so the body's functions can be supported.

High-dose anticoagulants are used to stop the blood clots getting bigger while they're slowly absorbed by the body.

But even with the best available treatment, an estimated 1 in 2 of people die as a result of the condition.