Sarah’s foot pain was dismissed by doctors as plantar fasciitis. Days later, she ended up in hospital fighting for her life. This is the little-known condition that was really to blame… and why so many GPs miss it

When Sarah Bassra’s leg became swollen and painful, she initially put it down to an ankle injury.

But the symptoms were the first sign of a potentially life-threatening medical condition.

It started two months prior, in June 2022, when she noticed her toes were red and feeling hot. Soon after, this spread to her ankle, which also became swollen and inflamed.

Two separate visits to the GP gave her different answers. At first, she was told it could be an allergic reaction to the gel nail polish she was using.

But when her symptoms progressed despite removing the nail polish, she returned to her GP, who said it was probably plantar fasciitis – a condition that causes pain on the bottom of the foot, around the heel and arch.

‘They told me to get orthopaedic trainers and sent me home without a blood test,’ says Sarah, now 36, from Nottingham.

But the pain continued, this time spreading up her calf and to her thigh.

‘I thought that maybe I was walking too much or overcompensating for the pain in my ankle by putting pressure on other areas,’ she says.

Then, during a day out at a music festival, she began experiencing chest pains and struggled to catch her breath. 

On her way to the taxi at the end of the night, she collapsed.

‘I thought I was having a heart attack,’ she says.

At A&E, a test revealed Sarah had deep vein thrombosis, which happens when a blood clot forms in a deep vein in the lower leg.

A separate scan found she also had a pulmonary embolism, a dangerous blockage in a lung artery caused by the blood clot travelling from the vein in her leg.

‘Now, looking back and knowing it was a blood clot, I could literally feel it travelling up my leg,’ she says. 

Sarah’s life was in danger and she spent five days in hospital and was put on a course of blood thinners, which prevent new blood clots from forming and keep existing clots from getting bigger.

It wasn’t until months later that she finally received a diagnosis that explained her symptoms.

The condition that caused Sarah’s blood clots is antiphospholipid syndrome (APS) – also known as Hughes syndrome.

APS is an immune system disorder that makes blood too ‘sticky’, raising the risk of dangerous blood clots and pregnancy problems like repeated miscarriages.

APS is thought to affect around 35,000 Britons – and is most prevalent in women aged 20 to 50.

Many people have no symptoms until a clot or pregnancy complication occurs.

Crucially, experts say the first signs of a blood clot include swelling, pain or tenderness, and warmth or redness in an affected arm or leg – but add that many GPs dismiss these symptoms, particularly in young people.

If a clot travels to the lungs, it becomes a medical emergency. Signs include sudden shortness of breath or trouble breathing, sharp chest pain that worsens when you breathe in or cough, a fast or irregular heartbeat and coughing up blood.

Experts believe the condition is present in roughly one in six cases of young strokes, deep vein thrombosis and heart attacks under the age of 50.

But research shows it is too often missed by GPs. 

A 2023 study found that nearly 15 per cent of patients with APS were diagnosed late or misdiagnosed, often waiting more than seven years for the correct diagnosis.

Professor Beverley Hunt, an expert in APS and founder and co-chair of trustees of Thrombosis UK, says: ‘Clots are missed because medical professionals are looking for the wrong thing. 

‘About 80 per cent of deep vein thromboses don’t present as the big, swollen leg we were taught about, so people with unexplained leg pain or swollen ankles and toes are often sent away until the clot reaches their lungs. 

‘Our research shows people with deep vein thrombosis often see doctors several times before anyone recognises the clot, simply because healthcare professionals aren’t aware of how varied and subtle the symptoms can be.’

APS can run in families and experts believe lifestyle factors like poor diet, not exercising enough and smoking can increase the likelihood of developing the condition.

Certain medications, including the combined contraceptive pill, can also trigger the condition in some people.

Unmanaged APS can also restrict blood flow to the placenta, causing pregnancy complications, such as miscarriages or late stillbirths.

When diagnosed early, the condition can be safely and effectively managed with daily blood-thinning tablets or, for those pregnant, even more potent blood-thinning injections.

Sarah says that ‘in a way’ she is grateful she collapsed at the festival because it forced a diagnosis and treatment. 

‘I think the GP thought I was being overdramatic when I went to them with my swollen ankle,’ she says.

‘All it would have taken was a simple blood test for them to see it was a blood clot and they would have caught it two months earlier.’ 

Sarah, who has been told she will likely have to take blood thinners for life, says the drugs come with lots of side effects.  

‘It was really scary at the beginning,’ she says. 

‘My hair started falling out and the drugs made my periods heavier, which really impacted me.

‘For the first two years, I didn’t have a holiday because I was just so worried that I would get a blood clot on a flight.

‘I also started getting out of breath really easily on 30-minute walks because of the damage to my lungs. It’s probably taken about three years for this to stop happening.’

She hopes her experience highlights to others the importance of getting a second opinion if they suspect something is not right. 

‘There is an assumption that blood clots are things that happen to old people – but I was in my early 30s when this happened,’ she says. 

‘If I had got a second opinion and diagnosis sooner, it would have never spread to my lungs and I wouldn’t have permanent damage.’

Professor Hunt says unexplained leg pain, new swelling or colour changes in your foot or ankle and chest pain should always be taken seriously. 

‘They may be subtle,’ she says. ‘But these symptoms can be the earliest clues that a dangerous clot is forming.’