What are the causes and significance of an abdominal bruit?
• Normal: Approximately 5%–25% of normal individuals may have a midsystolic bruit audible, with the prevalence being higher in younger individuals.
• Renovascular disease: The characteristic bruit seen in renovascular hypertension, due to renal artery stenosis, is an epigastric systodiastolic bruit. Although it has a low sensitivity, it has a high specificity in the patient in whom one is suspecting renovascular hypertension. Renovascular hypertension can be due to either atherosclerotic disease or fibromuscular dysplasia (typically seen in young or middle-aged women). In fibromuscular dysplasia, extrarenal disease is common, with cervicocranial and other abdominal arteries being involved in particular.
• Nonrenal causes of abdominal bruit include portal hypertension (periumbilical venous hum), pancreatic neoplasia (epigastric bruit), splenic arteriovenous malformation (left upper quadrant), hepatic carcinoma (right upper quadrant), and abdominal aortic aneurysms.
