Deep vein thrombosis can affect anyone.
Ms Samantha Ng, 41, was two months pregnant with her first child in 2012 when she developed a blood clot in her left leg.
“When I woke up one morning, my left thigh was very painful,” said the secretary. “After the third day, it became more painful and it was swollen. My leg felt a bit warm and hard. When I pressed it, it felt like a stone.”
Not realising that it was a blood clot, she chose to ignore the pain until it got to the point where she could not walk properly. She had to borrow a wheelchair from her neighbour just to go to the general practitioner (GP) nearby. But the GP could not figure out the problem. A visit to a traditional Chinese medicine practitioner also led nowhere.
If the clot travels to the lungs and becomes lodged there, it becomes pulmonary embolism (PE), and is exceedingly dangerous if left alone. “Left untreated, more than 50 per cent of the patients with DVT will get PE,” said Dr Yap Eng Soo, a consultant at the haematology division of the department of haematology-oncology at the National University Cancer Institute, Singapore.
And one-quarter of the patients who show symptoms of PE could die within 14 days, if they are not treated. DVT and PE are known together as venous thromboembolism (VTE).
To prevent new clots from forming, Ms Ng had to inject herself with a blood thinning medication twice a day for the rest of her pregnancy and one month after she gave birth.
“Pregnancy, hormone replacement therapy and oral contraceptives are well-known factors for DVT,” said Associate Professor Lee Lai Heng, a senior consultant in the department of haematology at the Singapore General Hospital. But, she added: “Young and healthy mothers should not be allowed to die from something that is preventable and curable.”
These three risk factors all lead to a rise in oestrogen. This pushes up the concentration of clotting proteins in the blood, thereby increasing the tendency for the blood to clot, said Dr Yap.
It is not just pregnant women who are at risk. Out of 100,000 patients who are hospitalised in Singapore, around 100 are estimated to have developed VTE as a result of hospitalisation, said Dr Yap.
There is a lack of data here but doctors believe VTE diagnoses are on the rise because of greater awareness among health professionals, so the number is likely to be higher than what is currently reported, said Dr Yap.
Overall, however, a belief that VTE is rarer than it is means doctors are less likely to spot it. Furthermore, the disorder can sometimes produce no symptoms, making it hard to diagnose, said Dr Yap. If present, symptoms include pain or swelling of the lower limbs, which can also occur in many other conditions.
Nevertheless, patients should see a doctor for symptoms of unexplained lower-limb swelling, redness and pain or unexplained breathlessness, a fast heart rate and chest discomfort and pain, said Prof Lee, who is also chairman of the Asian-Pacific Society on Thrombosis and Haemostasis. “Although the symptoms are non-specific, they can be that of VTE.”
The risk is higher for people who have had recent surgery, an extended period of being immobilised or an underlying cancer, she said. She also urged doctors to be alert to how these symptoms could point to a diagnosis of VTE, especially in someone who has the right risk factors.