The onset of DVT may be silent or heralded by pain in the
calf, often about 10 days after immobilization for
surgery, parturition or an infection. The leg becomes
swollen and cyanotic distal to the thrombus. The calf
may hurt when handled or if the foot is dorsiflexed
(Homans sign). Sometimes a pulmonary embolus is
the first sign of a silent deep vein thrombosis.
Suitable investigations include venography, Doppler
ultrasonography, which can only detect thrombi in
large veins at, or above, the popliteal fossa, and
I-fibrinogen isotope leg scanning.
Treatment is anticoagulation with heparin and
later with a coumarin. The value of thrombolytic
regimens has yet to be assessed properly. Prevention
is important. Deep vein thrombosis after a surgical
operation is less frequent now, with early postoperat-
ive mobilization, regular leg exercises, the use of elastic
stockings over the operative period and prophylaxis
with low dose heparin.
