Deep Vein Thrombosis

Deep vein thrombosis (DVT) is the formation of a blood clot in a deep vein, most often in the leg. It is a serious condition because part of the clot can break off and travel to the lungs, causing a potentially fatal pulmonary embolism.

• Swelling of one leg (or arm), often more noticeable than the other side
• Pain or tenderness, often starting in the calf
• Warmth and redness over the affected area
• Sudden breathlessness, chest pain, or coughing up blood may indicate the clot has moved to the lungs (pulmonary embolism) — a medical emergency

• Prolonged immobility, such as after major surgery, long-distance travel, or extended bed rest during illness.
• Pregnancy and the postpartum period.
• Use of oestrogen-containing hormonal contraception.
• Underlying cancer, obesity, dehydration, and inherited or acquired clotting disorders.
• Trauma or surgery to the legs or pelvis.

• Diagnosed clinically using a structured risk assessment (such as the Wells score) combined with imaging.
• Doppler ultrasound of the affected limb is the standard confirmatory test where available.
• D-dimer blood testing may support diagnosis in lower-risk cases, though it is not specific on its own.
• Suspected pulmonary embolism requires urgent hospital assessment, which may include chest imaging.

Anticoagulant (blood-thinning) medicine is the mainstay of treatment, started promptly once DVT is confirmed or strongly suspected, to prevent the clot from growing or embolising to the lungs.

Initial treatment is commonly with a heparin-type injectable anticoagulant, often transitioned to or combined with an oral anticoagulant such as warfarin, with the duration of treatment (typically at least three months) depending on the cause and risk of recurrence.

Compression stockings and encouraging leg movement help reduce swelling and long-term complications.

Patients with signs of pulmonary embolism — sudden breathlessness, chest pain, or coughing blood — require immediate emergency referral, as this is a life-threatening complication.

• Stay mobile and move the legs regularly during long journeys or periods of bed rest.
• Stay well hydrated, particularly during travel or illness.
• Use preventive anticoagulant medicine or compression devices as prescribed after major surgery, when at high risk.
• Seek early assessment for unexplained leg swelling or pain rather than waiting.