Clinical features of DVT
Symptoms
Symptoms may not be present in up to 50% of those with a DVT, but those with symptoms complain of a swollen and painful calf of the leg, which is warm to the touch.
Signs
50% of people with a DVT may not exhibit signs.
- The leg and calf are warm to the touch, and swollen. Depending on the site of the thrombosis, the thigh or the foot may be swollen as well. The foot is warm and not pale. Pulses may be hard to feel because of swelling (oedema) of the foot and leg, but can be detected by ultrasound Doppler. The Ankle/Brachial index and the capillary blood flow are usually normal, except in severe disease, where compartment syndrome will constrict the arterial blood flow.
Compartment syndrome is excessive swelling of injured muscles within the muscle compartments in the leg, usually caused by fracture or crush injury or arterial insufficiency. It has to be relieved surgically in order to save the circulation and the tissues in that compartment.
Homan’s sign may be elicited: (with the knee of the affected leg flexed, the examiner forcibly dorsiflexes the foot that is, brings the toes upward. Resulting pain in the calf of the foot may be consistent with deep venous thrombosis).
These symptoms and signs are consistent with an obstruction to the venous drainage of the leg.
Differential Diagnosis of DVT
DVT may be mimicked by anything that is likely to cause calf muscle pain, such as:
- Non-specific muscle pain
- Compartment syndrome
- Ruptured Baker’s cyst behind the knee. (A Baker’s Cyst is an extension of joint fluid which exists in a sac as an extension of the knee joint capsule, and causes a swelling behind the knee). Rupture of the cyst causes inflammation, with associated symptoms.
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Amended April 2008
