Patient assessment - examination
On inspection of the leg, in addition to any ulcers or gangrene, there may be loss of hair, thickening of toenails and thinning of the skin. The foot becomes very pale on elevation and red when put on the ground. This is called Buerger's sign and is shown by the foot on the left in the picture below:
Severe disease may present with gangrene:
Despite the red appearance, the foot will be cold to the touch.
The pulses in the leg will be felt for:
 | Femoral - in the groin |
| Popliteal - behind the knee |
| Dorsalis pedis - in the foot (this may be missing in 10% of the normal population) |
| Posterior tibial - behind the inner ankle |
The distribution of missing pulses will give an indication of the part of the arterial tree of the leg that is diseased.
To give a more accurate picture the blood pressure at the ankle is measured using a hand-held doppler and a blood pressure cuff:
The highest pressure at the ankle is compared to the highest arm pressure to give an index, the Ankle Brachial Pressure Index (ABPI). This is used to give an estimate of disease severity.
In some cases there may be areas of gangrene but with a full set of pulses. This indicates disease in the very small blood vessels supplying the skin - these may become blocked by very small blood clots, inflammation in the arteries (vasculitis), Buergers disease or severe spasm (frostbite and Raynaud's syndrome).