A 62-year-old man comes to the office due to poorly localized, intermittent abdominal pain that is triggered by eating and slowly subsides over the ensuing several hours. The patient has also lost 4.5 kg (10 lb) over the past 2 months. He has a history of hypertension and hyperlipidemia and has smoked a pack of cigarettes daily for 40 years. Blood pressure is 175/105 mm Hg and pulse is 70/min and regular. The abdomen is soft and nontender. CT scan of the abdomen reveals the renal findings shown in the image below.
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This patient most likely suffers from which of the following conditions?
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This patient has postprandial pain and a 4.5-kg (10-lb) weight loss as well as multiple risk factors for atherosclerosis (eg, advanced age, hypertension, smoking). This presentation is highly suggestive of chronic mesenteric (intestinal) ischemia. Atherosclerotic narrowing of the abdominal (superior mesenteric or celiac) arteries results in reduced blood flow to the intestine; during periods of high metabolic requirement (ie, after eating), patients can develop "intestinal angina" (dull, cramping abdominal pain that resolves 2-3 hours after meals).
Atherosclerosis is a multiorgan disease, and patients often have involvement of other major vessels, including coronary artery disease, carotid stenosis, peripheral vascular disease, and renal artery stenosis (RAS). Atherosclerotic RAS often becomes apparent at age 60-70 and is typically associated with prominent atherosclerotic plaques at the junction of the aorta and the renal artery. Less frequently, nonatherosclerotic RAS occurs secondary to fibromuscular dysplasia, a disease that affects predominantly younger women and causes narrowing of multiple renal artery segments (string-of-beads appearance).
In unilateral RAS, chronic ischemia atrophies the affected kidney while the contralateral kidney undergoes compensatory hypertrophy, leading to renal size discrepancy, as seen in this patient. Renal hypoperfusion also activates the renin-angiotensin-aldosterone system, resulting in hypertension that is often refractory to medications. Abdominal and flank bruits are highly suggestive of RAS. Light microscopy of the atrophic kidney reveals tubular atrophy with decreased tubular epithelial size, patchy inflammation, and tubulointerstitial and glomerular fibrosis.
Educational objective:
Marked unilateral kidney atrophy is suggestive of renal artery stenosis. It occurs in elderly individuals due to atherosclerotic narrowing of the renal artery and is often seen in association with other atherosclerotic risk factors or diseases (eg, chronic mesenteric ischemia, coronary artery disease, peripheral vascular disease). Hypertension and abdominal and flank bruits are often present.