A 62-year-old man complains of right-sided leg and thigh pain while walking. The pain improves with rest and is described as a heaviness or cramping sensation. His sexual performance has decreased over the past year. The patient's other medical problems include chronic kidney disease, type 2 diabetes mellitus, hypertension, hyperlipidemia, and gastroesophageal reflux disease. He has a 38-pack-year smoking history.
The patient's blood pressure is 144/72 mm Hg, pulse is 67/min, and body mass index is 29 kg/m². A bruit is heard over the right carotid artery. Peripheral pulses are palpable bilaterally. There is a small ulcer at the tip of the right big toe. No extremity edema is present.
The ankle-brachial index is 1.45 on the right and 1.40 on the left (normal 1.0-1.3) . The serum creatinine is 2.2 mg/dL and HbA1c is 7.5%.
Which of the following is the most likely cause of this patient's leg pain?

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11ec193a_9768_86d6_853d_7b0dedfdae2a_MD0002_00 This patient has several risk factors, along with clinical symptoms and signs (intermittent claudication, erectile dysfunction, lower-extremity ulceration) suggestive of occlusive peripheral arterial disease (PAD). Measurement of ankle-brachial index (ABI) is recommended in such patients to confirm the diagnosis of PAD. An ABI of 1.0-1.3 is considered normal; in symptomatic patients, an ABI of <0.90 is considered diagnostic of occlusive PAD with 90% sensitivity and 95% specificity. Some patients with PAD and arterial calcification have non-compressible vessels, which can lead to falsely elevated ABI (>1.3). This is usually seen in the setting of diabetes mellitus and/or chronic renal failure. In such patients, further vascular studies, with measurement of toe-brachial index, pulse volume recordings, or arterial duplex ultrasound, should be obtained to confirm the diagnosis of PAD. The presence of high ABI >1.3 (similar to low ABI) is associated with an increased risk of all-cause and cardiovascular mortality. < (Choice A) Diabetic neuropathy usually presents with bilateral sensory polyneuropathy involving the distal lower extremities, with decreased sensation to light touch, pain, and temperature, and loss of vibration sense and proprioception. Patients with florid neuropathy also complain of pain, paresthesias, or dysesthesias of their feet. The quality and exertional pattern of this patient's symptoms are not consistent with diabetic neuropathy. (Choice C) Lumbar spinal stenosis typically presents with "neurogenic claudication," with bilateral or asymmetric lower-extremity pain, weakness, or sensory loss that is exacerbated with walking or prolonged standing in erect postures. It is relieved with sitting or assuming a stooped and flexed posture. (Choice D) Statin-induced myopathy generally develops within weeks to months after starting statins and can present with muscle weakness, myalgias, and myositis (with elevated creatine kinase). The symptoms are usually more diffuse (and not localized as in this patient) and affect both upper and lower extremities. (Choice E) "Venous claudication" is occasionally used to describe the lower-extremity discomfort in patients with chronic venous disease. These patients usually have associated findings of venous disease with leg swelling and varicosities, and the symptoms are worse with the limbs in a prolonged dependent position. Educational objective: A falsely elevated ankle-brachial index (ABI) >1.3 can be present due to calcified and non-compressible arteries in patients with advanced peripheral arterial disease in the setting of diabetes and/or chronic renal failure. High ABI (similar to low ABI) is associated with an increased risk of all-cause and cardiovascular mortality. __________ References: Exertional leg pain in patients with and without peripheral arterial disease. (http://www.ncbi.nlm.nih.gov/pubmed/16316971) Relationship of high and low ankle brachial index to all-cause and cardiovascular disease mortality: the Strong Heart Study. (http://www.ncbi.nlm.nih.gov/pubmed/14970108)

A 62-Year-Old Man Complains of Right-Sided Leg and Thigh Pain