Formation of a blood clot in a vein, in the lower extremities, which partially or completely impedes blood flow. DVT is a medical emergency. Thrombus dislodgement may precipitate pulmonary embolus.
Risk factors to look for in the case history include: immobility, trauma, familial thrombophilia, COP/HRT, pregnancy, dehydration, increased age, obesity, male gender, previous DVT, heart failure, cancer, vasculitis.
DVT can be asymptomatic but typical presentation is unilateral tightness or pain in the lower limb (usually calf muscle area) exacerbated by walking or standing. Visual examination and palpation of the affected leg may reveal: oedema (can be pitting), changes in cutaneous colouration (redness or cyanosis) and warmth. Superficial veins can also be engorged. If venous engorgement persists with limb elevation above 45 degrees this is suggestive of DVT.
Homansâ€™ sign is not recommended for diagnosis of DVT as it is insensitive or nonspecific and may, theoretically dislodge the clot. Doppler testing methods represent the most accurate means of assessing DVT, morphological changes and blood flow.