A chap in his mid-fifties, accompanied by his wife, wanted a swollen ankle sorted out before flying home to England next day. They had arrived in Australia three weeks previously for a holiday with relatives. He mentioned, too, that one week previously he had experienced some severe chest pain and shortness of breath. A doctor had done an ECG and told him everything was fine. Alarm bells were already ringing in my mind but the only physical abnormalities I could find were mild swelling of his left ankle and the circumference of his left calf exceeded that of the right calf by four centimetres.
I explained that it was possible he had a deep vein thrombosis in his left leg - given the swelling and the fact he had flown out from England three weeks previously. He thought the flight was now far too distant to be associated with DVT but I assured him it was not. I did not mention that I was also worried the chest pain may have been due to a pulmonary embolism – clots coming from the leg and lodging in the lungs. He agreed to wait two hours for the earliest possible Dopler ultrasound – the definitive test for deep vein thrombosis.
The ultrasound technologist came to see me, immediately after completing the procedure, to inform me that there was extensive clotting in the patient’s left leg extending well above the knee. We both went off to see the radiologist for his specialist opinion. He confirmed the presence of clots and suggested we should immediately do a Computerised Tomography Pulmonary Angiogram (CTPA). This we did and within the hour had confirmed the presence of, not one, but numerous small blood clots in both lungs.
This devastating news had to be conveyed to the patient and his wife who, dutifully, remained at his side. They were alarmed initially at the impact of the diagnosis on his ability to fly home next day. I told them there was no possibility of that happening and they would have to cancel. I explained that we would happily give them a letter to confirm he had developed a medical condition that prevented him from flying. It was necessary for me to explain that, quite apart from the impact on their travels, his condition was life-threatening. Understandably, when the reality of that set in, they were both distressed.
The distress was tempered with the information that the condition can be treated with high success rates. We arranged admission to hospital and for a battery of blood tests including a detailed assessment of his blood clotting mechanisms and a baseline INR level. Then he was given an injection of Clexane – a derivative of heparin which is a quick acting anticoagulant. The aim was to prevent any further development of the clots. This was followed by a first oral dose of warfarin which takes about five days of a daily dose to work by inhibiting the effects of vitamin K on the clotting mechanisms. Ongoing dosage is monitored with a regular blood test known as an INR which measures the time taken for a blood sample to clot. When that reaches a therapeutic level the Clexane is ceased.
This unfortunate chap and his wife had their holiday ruined by the sudden onset of an unexpected illness.
Of all the millions of people who fly long distances relatively few suffer this problem but it is a common occurrence. Sitting for long hours in, usually, cramped seats causes blood flow in the legs to decrease and/or become turbulent. Both mechanisms cause blood to clot and once a clot forms it gets bigger. He was very lucky that one large clot did not break free and obstruct the blood flow through the heart and lungs – a common cause of death in such circumstances.
There are numerous high risk factors, other than flying, for deep vein thrombosis. Pregnancy, oral contraceptive pills, cancer, limb immobilisation with splints and plaster casts etc, surgery, prolonged immobilisation in bed, and some congenital clotting disorders, are all well recognised as associated with DVT. Pulmonary embolism still causes a significant number of deaths despite its causes, prevention and treatment being well known. What greater tragedy can there be than a young mother, delivered by Caesarian section and refusing prophylactic anticoagulants, developing DVT and fatal pulmonary embolism two weeks after the arrival of her first baby?
We do a lot of investigations to rule out DVT and PE. For example, an elderly person presenting with a swollen leg, perhaps with varicose ulcers or an infected scratch must have DVT excluded or diagnosed as the case may be. The only definitive practical investigative tool is the Dopler ultrasound. There is a blood test, D-Dimer estimation, but the incidence of false positives and false negatives is far too great to rely upon it in isolation. We must also consider the problem occurring in the arms or pelvis in some people – it is not solely a problem occurring in the veins of the legs. An acquaintance of mine had an hereditary blood clotting disorder and also had the habit of sitting on upright chairs with one arm dangling over the back of the chair. He inevitably developed a blood clot in one arm and required anticoagulation while it cleared up. Even so, despite this life threatening condition, he still needed to be chastised for dangling one or other arm over the back of chairs.
The management of DVT has changed over the years and continues to change. Not long ago the discovery of even a small clot in a deep leg vein demanded immediate admission to hospital for anticoagulation etc. Nowadays, things are different. Blood is taken for the baseline tests, an injection of Clexane is given and a Warfarin tablet given. The patient is most often sent home with a prescription for both and a request form for a blood test to be done in five days and advised to see the GP at first available appointment after that blood test. The patient is required to self administer the Clexane injection or have spouse or other inject it – it is quite simple - and to take a Warfarin tablet daily.
Complicated patients such as pregnant women, those with ultrasound-proven massive blood clots and those with symptoms of serious pulmonary embolism – among others - will be admitted under specialist care.
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