Intermittent Claudication

Early peripheral arterial disease (PAD) commonly presents as claudication, a term derived from the Latin claudico meaning “to limp.” (Ward, 1998) Intermittent claudication is described in the literature as a transient, exercise induced ischemic myalgia characterized by aching, cramping, tiredness, or tightness of the affected muscle compartment (Ward, 1998). The calf being the most commonly effected (Ward, 1998). When normal muscles are exercised , metabolic by-products are released resulting in relaxation of smooth muscle in the arterioles, venules and pre-capillary sphincters. The resistance in these vessels greatly decreases. Since blood flow is inversely proportional to resistance, blood flow to the healthy exercising muscle will increase 10-20 times and thus meet the increased metabolic demands of that muscle, removing the noxious metabolic end products (Ward 1998).

When an individual with significant organic occlusion participates in exercise, relaxation of the smooth muscle in the arterioles, venules and pre-capillary sphincters still occurs, a problem arises due to the fact that the occluded vessel is narrowed and uneven due to plaque deposition. The amount of blood that is able to pass this occlusion per unit time is greatly limited, the end result being that the demand of the exercising muscle is not met. Pain is felt when the accumulation metabolic by-products within the muscle is at high enough concentrations to activate pain receptors, more exercise results in more pain. Once the individual stops exercising, the rate of metabolism within the muscle decreases, the blood flow to the muscle can then wash away the high levels of metabolites and the individual will then achieve symptomatic relief (Ward, 1998).

The locality of pain usually correlates with the location of the occlusion, pain is usually perceived one segment distal to the obstruction, i.e., toe pain usually reflects an occlusion in the midfoot, calf pain an occlusion in the knee or distal thigh and so forth (Hoffman 1992). It is important to correlate the patients history with the physical findings and to clearly identify whether the patients pain is of ischaemic origin, and to exclude any differential diagnoses’. Ischemic pain is worse during exercise and is located in muscles, whereas arthritic pain is located in joints, the patient who’s pain is of ischaemic origin is more likely to suffer earlier onset of symptoms when walking up hills. Pain of neurologic origin probably correlates with back pain and is noticed in specific positions (Hoffman. 1992). If the patients main presenting complaint is more severe at rest and the patients ABPI is greater than 0.8, the pain is not likely to be of ischemic origin. It is important to ascertain and note how far the patient can walk before requiring rest, this allows a semi-quantitative measure for future inquiries, it is also important to enquire as to any changes/progression the pain has made since it was first noticed.

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Last Updated: October 24th, 2001