Deep vein thrombosis (DVT) in Cairns
A calf that becomes swollen, tight and painful over a day or two, often on one side only, is the classic presentation of a deep vein thrombosis. The leg may feel warm and look flushed. Sometimes the only sign is a dull ache that does not settle.
DVT needs to be diagnosed quickly, because a clot in the deep veins of the leg can travel to the lungs. If you have new, unexplained swelling in one leg, see your GP the same day or attend an emergency department. If you also have chest pain or breathlessness, treat that as an emergency and call 000.
What a DVT is
A thrombus is a blood clot. When one forms in the deep veins — the large vessels that run inside the muscle compartments of the calf, thigh and pelvis — it is a deep vein thrombosis.
The clot obstructs the vein, so blood cannot drain out of the leg normally. That produces the swelling, the tightness and the pain. Two things can then go wrong. Part of the clot can break away and lodge in the lungs, which is a pulmonary embolism. Or the clot can damage the valves inside the vein as it resolves, leaving the leg with permanent venous reflux — post-thrombotic syndrome.
What raises the risk
Clots form when blood flow slows, when the blood is more prone to clotting than usual, or when a vein wall has been injured. In practice that means:
- Prolonged immobility — long-haul flights and drives, hospital admission, a leg in plaster
- Recent surgery, particularly hip, knee and abdominal procedures
- Cancer and some cancer treatments
- Pregnancy and the six weeks after delivery
- The combined oral contraceptive pill and hormone replacement therapy
- An inherited clotting tendency, or a previous DVT
- Increasing age, obesity, smoking and dehydration
In Far North Queensland, dehydration in the heat and long drives between centres are both worth taking seriously as contributing factors, particularly around holiday travel.
Recognising it
The typical picture is one leg, not both:
- Swelling of the calf, or the whole leg if the clot extends into the thigh or pelvis
- Pain or tenderness, often described as a deep cramp, worse on walking
- Skin that feels warm, and may look red or dusky
- Veins near the surface that become more prominent than usual
Symptoms suggesting the clot has travelled to the lungs — sudden breathlessness, sharp chest pain worse on breathing in, coughing blood, feeling faint — require emergency assessment, not a specialist appointment.
Swelling in both legs is more often something other than DVT. That does not make it unimportant, but it changes what needs to be looked for.
How it is diagnosed
Diagnosis is made on duplex ultrasound. The scan shows whether a vein can be compressed, whether blood is flowing through it, and how far any clot extends. It requires no needles, dye or radiation.
A blood test called a D-dimer is often used first in general practice. It is useful for ruling a DVT out when the clinical suspicion is low; a raised result on its own does not confirm one.
Scans at this practice are performed on site at Lake Street by our sonographer, Jovin, which allows imaging and specialist review in the same visit. Where a DVT is suspected acutely, this is not the pathway — go to your GP or the emergency department for same-day imaging.
Management
Most deep vein thromboses are treated with anticoagulation — medication that stops the clot extending and allows the body to break it down over time. Which agent is used, and for how long, depends on where the clot is, what caused it, whether it is a first episode, and your bleeding risk. Three months is a common starting point, and some people need longer or indefinite treatment.
Compression is used alongside anticoagulation to control swelling and reduce the risk of long-term skin damage.
A minority of cases need more than medication.
Thrombolysis. Where a large clot involves the thigh or pelvic veins in a younger patient with a heavily swollen leg, dissolving the clot directly can preserve valve function and reduce long-term consequences. It carries a meaningful bleeding risk and is reserved for selected cases.
Vena cava filter. A device placed in the main abdominal vein to catch clot travelling toward the lungs. It is used when anticoagulation cannot be given or has failed, not as a routine measure. Filters are generally intended to be removed once they are no longer needed.
Both of these are decisions made on the specifics of the individual case.
Post-thrombotic syndrome
Between a third and a half of people who have had a DVT develop some degree of long-term venous problem in that leg. The valves damaged by the clot no longer close, so the leg carries high venous pressure.
The result is chronic swelling, aching and heaviness that worsen through the day, sometimes with the skin changes that precede venous ulceration. It is the main reason DVT deserves proper follow-up rather than being considered finished when the anticoagulant stops.
Where post-thrombotic syndrome develops, management centres on well-fitted graduated compression, skin care and walking. In selected cases where a pelvic vein remains blocked or narrowed, further investigation and intervention may be appropriate.
When a vascular surgical opinion is useful
Not every DVT needs a vascular surgeon. Uncomplicated calf and thigh clots are usually managed well in general practice. A specialist opinion is worth seeking when:
- The clot involves the iliac or femoral veins and the leg is heavily swollen
- Symptoms persist or the leg remains swollen months after the acute episode
- There have been repeated episodes
- Anticoagulation cannot be used, or has failed
- Skin changes or ulceration are developing in a leg with a previous DVT
- Varicose veins are being considered in a leg that has previously had a clot
Common questions
How long does the swelling take to settle?
Often several weeks, sometimes months, and in some legs it does not fully resolve. Consistent use of compression during that period makes a real difference to the eventual outcome.
Can I fly after a DVT?
This depends on how recent the clot is and whether you are anticoagulated. It needs to be discussed with the doctor managing your anticoagulation before you book. Do not assume a blanket answer either way.
Will I get another one?
The risk of a further clot depends heavily on why the first one happened. A DVT after an operation or a plaster cast carries a lower recurrence risk than one that occurred without any obvious cause. This is one of the factors determining how long you stay on treatment.
Is a DVT related to my varicose veins?
Not directly, though the two can occur in the same leg and a previous DVT changes how varicose veins should be assessed and treated. Superficial thrombophlebitis — a clot in a surface vein — is a different condition, but it can extend into the deep system, so it is not something to dismiss.
Should my family be tested for a clotting disorder?
Sometimes, particularly with clots occurring at a young age, in unusual sites, or with a strong family history. It is a decision made case by case, usually with haematology input.
Referral and appointments
Acute suspected DVT is not a clinic appointment. Please attend your GP or the Cairns Hospital emergency department for same-day imaging.
GPs and referrers: for post-thrombotic assessment, recurrent disease, or complex venous cases, referrals can be sent to the rooms by fax or through the online referral form.
Patients: phone the rooms on (07) 4254 5006. Suite 9, Level 1, 193 Lake Street, Cairns.