Deep Vein Thrombosis

Key points

• One-sided swelling, tenderness and warmth raise suspicion, but symptoms alone cannot confirm or exclude DVT.
• Clinical probability, D-dimer and compression ultrasound are combined to make diagnosis efficiently.
• Anticoagulation prevents extension and embolism; duration depends on cause, recurrence risk and bleeding risk.

The listings below are not safe to start for an unconfirmed swollen leg; diagnosis and anticoagulant selection require clinical assessment.

Assessing the clot and trigger

Recent surgery, immobility, pregnancy, oestrogen use, active cancer and previous clot raise risk. Ultrasound evaluates proximal leg veins, while repeat imaging may be needed when suspicion remains. Clinicians distinguish a provoked event from an unexplained one because this affects duration and further evaluation.

Anticoagulant decisions

Direct oral anticoagulants, heparins and warfarin have different roles in pregnancy, cancer, kidney disease and antiphospholipid syndrome. Treatment requires interaction and bleeding review. Compression may help selected persistent symptoms but does not replace anticoagulation.

When to seek urgent care

Call emergency services for sudden breathlessness, chest pain, coughing blood, fainting or a rapidly worsening painful swollen leg. Seek urgent help for uncontrolled bleeding while taking an anticoagulant.

Further reading

• What is Venous Thromboembolism (VTE)? | American Heart Association
• VENOUS THROMBOEMBOLISM - Thrombosis UK
• About Venous Thromboembolism (Blood Clots) - CDC