Arterial Insufficiency (Peripheral Artery Disease)

The pain of arterial insufficiency (intermittent claudication) is usually described as soreness, a cramp, or a burning sensation in the calf. The discomfort may also be described as tightness, heaviness, tiredness, or achiness rather than pain. The discomfort is usually precipitated by walking and relieved by rest. It rarely occurs while the patient is at home. It usually develops after the patient has walked a predictable (by the patient) distance and is relieved by rest in a standing position after a predictable (by the patient) time. After resting, the patient can resume walking a similar distance before the pain starts again; relief is achieved again after resting.

A common mistake is the diagnosis of osteoarthritis of the hip when gluteal claudication is the problem. This error is more likely if buttock pain is not associated with pain in the calf. Some patients with vascular disease of the iliac artery complain only of the symptoms of gluteal claudication, which are usually felt when the patient walks outside.

Rest pain (often nocturnal) in the toes or heel is almost pathognomonic of arterial insufficiency

The leg of a patient with arterial insufficiency may have pallor on elevation, rubor on dependency, and loss of hair on the toes. Some men with aortoiliac disease may present with pain in the upper leg or the buttock and an inability to develop or sustain an erection. Pain from intermittent claudication is usually unilateral but can be bilateral. When the pain is present bilaterally, it seldom occurs in both legs simultaneously. The onset of pain in one leg may prevent the patient from walking enough to produce symptoms in the other leg. Physical examination for evidence of arterial insufficiency must therefore be performed on both legs. Comparing the blood pressure of the ankle and the arm provides the ankle-brachial index (ABI). An ABI less that 0.9 is abnormal. An ABI less than 0.4 is suggestive of severe peripheral artery disease.

Venous Insufficiency

Venous claudication is difficult to distinguish from claudication due to arterial insufficiency. In both conditions, walking causes calf pain that may be severe enough for the patient to stop walking. Patients with venous claudication usually have no physical signs of arterial insufficiency.

Spinal Stenosis

Spinal stenosis is another cause of leg pain that is exacerbated by exercise. The pain (pseudoclaudication) is similar to that associated with arterial insufficiency; it also occurs more frequently in older men. The first clue that the pain in the leg is not caused by arterial insufficiency is the presence of normal pedal pulses. Although both begin with exercise, the pain of spinal stenosis is less often relieved by rest than the pain of arterial insufficiency (Table 24-1). The pain of intermittent claudication is relieved within a few minutes, whereas the pain of spinal stenosis requires 10 to 30 minutes to subside. Some patients with calf pain from spinal stenosis state that they must sit or lie down with the thighs flexed to relieve the discomfort.

Table 24-1 Comparison of Symptoms and Signs in Vascular and Spinal (Neurogenic) Claudication

The pain of spinal stenosis is caused by localized narrowing of the spinal canal due to a structural abnormality that results in cauda equina compression. Patients occasionally complain of backache or buttock pain as well as numbness and tingling in the feet with walking. Walking uphill is easier than walking downhill for these patients. They have no problem riding a bicycle, probably because the stooped position assumed during this activity reduces the amount of cauda equina compression. The examiner must remember that vascular claudication and spinal stenosis can coexist.

Thrombophlebitis

Unilateral pain and swelling in the calf are usually caused by thrombophlebitis. The pain is usually present at rest and is seldom worsened by exercise. In a patient with thrombophlebitis who experiences calf pain while walking, acute exacerbation of the calf pain occurs immediately after the foot is placed on the ground. Although the history and physical examination of thrombophlebitis are well known to most physicians (i.e., pain, swelling, tenderness on palpation, occasionally a history of prior trauma or previous bouts of phlebitis), this relatively common cause of leg pain is often misdiagnosed. Several studies have suggested that venous ultrasonography should be used to confirm the clinical diagnosis because thrombophlebitis has often been incorrectly diagnosed in the absence of ultrasonographic evidence.