DVT

Deep vein thrombosis (DVT) is the formation of a blood clot in a deep vein, most commonly in the legs. It can also occur in the pelvis or upper extremities. If a thrombus dislodges, it may travel to the lungs and cause a pulmonary embolism, a potentially life-threatening complication.

DVT results from Virchow's triad: venous stasis, endothelial injury, and hypercoagulability. Risk factors include recent surgery or trauma, prolonged immobilization, cancer, pregnancy, obesity, estrogen therapy, and inherited thrombophilias.

Clinical presentation varies. Many cases present with unilateral leg swelling and pain; the leg may feel warm and tender. Some DVTs are asymptomatic. Upper-extremity DVTs are often associated with central venous catheters or malignancy.

Diagnosis relies on clinical assessment and testing. The Wells score estimates pretest probability. A negative high-sensitivity D-dimer can exclude DVT in those with low probability. Duplex ultrasonography is the first-line imaging test; venography is rarely needed.

Treatment aims to prevent clot extension, embolization, and recurrence. Anticoagulation is standard, with direct oral anticoagulants (for example, apixaban, rivaroxaban) or heparin followed by a vitamin K antagonist in many settings, typically for at least three months. Cancer-associated DVT is often treated with low-molecular-weight heparin or DOACs in selected patients. Compression stockings and early ambulation can help symptom relief.

Complications include pulmonary embolism and post-thrombotic syndrome, which can cause chronic leg swelling, pain, and ulcers.

Prevention focuses on risk factor modification and, when indicated, pharmacologic prophylaxis after surgery or during prolonged immobilization. Mechanical measures such as sequential compression devices may supplement pharmacologic methods.