AuscultifyRenal Artery Bruit: Where to Listen and What It Means
To listen for a renal artery bruit, place the diaphragm (or bell) in the epigastrium and then in each upper quadrant about 2 to 3 cm above and 2 to 3 cm lateral to the umbilicus, with the patient supine, breathing quietly, and before you palpate the abdomen. The bruit of renal artery stenosis is classically high-pitched, lateralized to one side and continuous (systolic-diastolic); a soft, purely systolic sound in the midline is far more common and usually benign.
Renal artery auscultation location and technique
The renal arteries come off the aorta at roughly the level of L1 to L2, which projects onto the anterior abdominal wall a few centimetres above and to either side of the umbilicus. That is where you listen. Some examiners also auscultate posteriorly at the costovertebral angle (the flank, just below the twelfth rib lateral to the spine), which is worth adding when the anterior exam is difficult or a flank bruit has been reported.
- Sequence. Auscultate before palpation; palpating first can stimulate bowel sounds that mask a bruit.
- Chest piece. The diaphragm is the usual choice because renal bruits tend to be higher pitched than carotid bruits; the bell is a fine alternative. Use light pressure.
- Breathing. Quiet breathing is enough. A brief end-expiratory pause helps if bowel or breath sounds intrude.
- Sites. Midline epigastrium (aorta), then right and left upper quadrants (renal arteries), then the lower quadrants (iliac arteries), then the groin (femoral arteries).
- Time. Listen through several cardiac cycles at each site. Decide whether any sound stops at end-systole or runs on into diastole.
Site-by-site summary
| Site | Patient position | Chest piece | Typical sound | Significance |
|---|---|---|---|---|
| Epigastrium (aorta) | Supine | Diaphragm | Soft systolic bruit | Often benign in young thin people; aortic or mesenteric disease in older patients |
| Right or left upper quadrant, 2 to 3 cm above and lateral to umbilicus (renal) | Supine | Diaphragm or bell | High-pitched, lateralized; systolic or systolic-diastolic | Renal artery stenosis; continuous bruit is far more specific than systolic alone |
| Costovertebral angle (flank) | Sitting or prone | Diaphragm | Same as anterior renal site | Alternative window for renal artery turbulence or renal AV malformation |
| Lower quadrants (iliac) | Supine | Diaphragm | Systolic bruit | Aortoiliac atherosclerosis, peripheral arterial disease |
| Groin below inguinal ligament (femoral) | Supine | Diaphragm | Systolic bruit | Femoral or iliac stenosis |
What a renal artery stenosis bruit sounds like
Three features raise your suspicion that an abdominal bruit is coming from a renal artery rather than the aorta:
- Lateralization. It is loudest to one side of the midline, in an upper quadrant or flank, rather than directly over the aorta.
- Pitch. It is relatively high-pitched and blowing.
- Timing. It continues into diastole. A persistent gradient across a tight lesion keeps flow turbulent after systole ends.
A systolic-only epigastric bruit is a different animal. Soft midline systolic bruits are reported in a sizeable minority of healthy young adults (prevalence figures vary widely by study, from a few percent to around a quarter), and in the absence of hypertension or vascular risk factors they are usually of no consequence.
Causes of a renal bruit
- Atherosclerotic renal artery stenosis. The commonest cause, typically in older patients with diffuse vascular disease, involving the ostium and proximal artery.
- Fibromuscular dysplasia. The classic cause in young women, affecting the mid and distal artery with a "string of beads" appearance on imaging. This is the group in which a continuous bruit is most often described.
- Renal arteriovenous fistula or malformation. Congenital, post-biopsy or post-traumatic; produces a continuous bruit and sometimes hematuria or high-output features.
When to go looking for one
Auscultate the renal arteries in every hypertensive patient, and listen with particular care when the story suggests renovascular hypertension:
- Hypertension that is resistant to three or more agents, or that appears before age 30 or abruptly after 55.
- Unexplained hypokalemia from secondary hyperaldosteronism.
- A rise in creatinine after starting an ACE inhibitor or ARB.
- Recurrent flash pulmonary edema with preserved ventricular function.
- Asymmetric kidney size on imaging, or widespread atherosclerosis elsewhere.
How much does the bruit tell you?
Sensitivity is low. In the studies summarized for the Rational Clinical Examination series, an abdominal bruit was present in well under half of patients with renal artery stenosis, so the absence of a bruit does not exclude the diagnosis. Specificity depends on what you hear: any systolic bruit is only moderately specific, while a systolic-diastolic bruit in the upper abdomen has a specificity close to 99 percent for renovascular hypertension, sources vary slightly. Put simply, a continuous lateralized bruit is a strong reason to image; a quiet abdomen is not a reason to stop thinking about the diagnosis.
Next steps
The usual first-line test is renal duplex ultrasound. CT angiography or MR angiography give better anatomical detail and are preferred when duplex is inconclusive or the patient is likely to proceed to intervention. Whatever the imaging shows, blood pressure control, statin therapy and cautious use of renin-angiotensin blockade remain the mainstay for atherosclerotic disease; fibromuscular dysplasia responds well to angioplasty.
Documentation
Describe location, timing and laterality. For example: "High-pitched systolic-diastolic bruit left upper quadrant, 3 cm above and lateral to the umbilicus, not heard in the midline or on the right. Aorta non-tender, no pulsatile mass." Or, for the common benign finding: "Soft systolic bruit midline epigastrium, no diastolic component, no lateralization."
Learn to hear the diastolic component
The whole significance of a renal bruit hinges on whether it stops at end-systole or keeps going. Auscultify's library of real clinical recordings covers vascular as well as heart, lung and bowel sounds, and its six quiz modes make you decide the timing before revealing the answer. The Spectrogram view (Pro) shows the sound running past S2 in a way your ear will learn to recognize, and spaced-repetition weighting brings back the ones you miss.
Train vascular sounds free →FAQ
Where do you listen for renal bruits?
In the epigastrium and both upper quadrants, about 2 to 3 cm above and lateral to the umbilicus on each side, with the patient supine and breathing quietly. The costovertebral angle in the flank is an alternative site. Auscultate before palpation.
What does a renal bruit sound like?
A renal artery stenosis bruit is classically high-pitched, blowing, lateralized to one upper quadrant or flank, and continues from systole into diastole. A soft purely systolic midline sound is much more common and often benign.
What is the renal artery auscultation location?
The renal arteries leave the aorta at about L1 to L2, which projects a few centimetres above and lateral to the umbilicus. Listen there on each side and add the costovertebral angle posteriorly if needed.
Does renal artery stenosis always cause a bruit?
No. A bruit is heard in well under half of patients with renal artery stenosis, so its absence does not exclude the diagnosis. A continuous bruit is much more specific but uncommon.
What is an upper abdominal systolic diastolic bruit?
A bruit in the epigastrium or upper quadrant that persists through the whole cardiac cycle. It indicates a lesion with a diastolic pressure gradient and is the classic finding of renal artery stenosis, especially fibromuscular dysplasia; an AV fistula can produce the same sound.
What is a flank bruit?
A bruit heard over the costovertebral angle in the back, below the twelfth rib lateral to the spine. It is another window on renal artery turbulence and points to renal artery stenosis or a renal AV malformation on that side.