Claudication derives from the Latin word claudicare and means “to limp.” It is caused by a reduction in blood flow to the leg muscles, most commonly by an atherosclerotic plaque. It is not due to a blood clot or embolization. The reduced arterial blood supply cannot meet the metabolic demand of the muscles utilized during walking. The diagnosis can readily be suspected based on the three-part definition obtained by history: (1) pain in the leg with walking, (2) relieved within a few minutes of rest, and (3) reproducible at the same walking distance each time.

Claudication is a symptom of peripheral arterial disease (PAD). PAD most often affects the lower extremities and less commonly the upper extremities and the intestinal and renal arteries. It is usually caused by atherosclerosis. It leads to a gradual slowly developing reduction in blood flow in the extremities (chronic limb ischemia).

Main risk factors for PAD include smoking, diabetes, hypertension, hypercholesterolemia, advanced age, male gender, obesity, sedentary lifestyle, family history of vascular disease, heart attack, and stroke.

The spectrum of severity is categorized by the Rutherford classification of chronic limb ischemia (Table 56.1)

Ischemic rest pain is a sign of advanced PAD (Rutherford class 4). It typically presents in the foot, most commonly in the toes (as that is the distal most part of the limb, where the blood has the hardest time reaching). It occurs at night when the patient is lying supine, as the arterial blood flow is so poor that gravity is needed to get blood to the foot. The patient wakes up with the toes aching or feeling numb and is forced to get up and either walk around or dangle the painful leg over the edge of the bed. In advanced stages, the patient has to actually sleep in an inclined bed or in a chair to keep the painful foot in a dependent position.

It is a physical examination sign of advanced chronic ischemia. The affected foot turns pale after it is elevated (usually for 1–2 min). Once the patient sits up and dangles the foot down, it becomes ruborous (like a cooked lobster). It is due to marked arteriolar dilation from chronic severe ischemia that causes a reactive hyperemia. Patients with ischemic rest pain typically will manifest Buerger’s sign. Such patients will also have multiple levels of arterial obstruction and an accompanying low ankle brachial index (ABI) of <0.4. The absence of Buerger’s sign makes ischemic rest pain very unlikely.

17 pulses (superficial temporal, carotid, brachial, radial, femoral, popliteal, posterior tibial, dorsalis pedis bilaterally, and aortic) should be examined.

PAD causes a progressive loss of blood supply to the leg. The calf muscles atrophy; hair appendages die (hair loss), as do sweat glands (dry scaly skin); the skin thins out (shiny); and ulcers may develop. Capillary refill time becomes prolonged (normal is ≤ 2 s).

Claudication may affect all the major muscle groups associated with walking, including the buttock, anterior thigh, calf, and rarely the foot muscles. The calf muscles are supplied by the superficial femoral artery (SFA). The SFA, which travels through the Hunter/adductor canal, is the most common site for atherosclerosis in the lower extremities; therefore, calf claudication is the most common location of pain. The internal iliac arteries supply the buttocks. Thus, stenosis above the internal iliac arteries (aorta, common iliac arteries) would cause buttock claudication. The hamstrings are not primarily utilized with walking. Thus, pain in the back of the thigh is not characteristic of claudication.