This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.
NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.
StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
StatPearls [Internet].
Show detailsContinuing Education Activity
A carotid bruit is a vascular sound usually heard with a stethoscope over the carotid artery because of turbulent, non-laminar blood flow through a stenotic area. A carotid bruit may point to an underlying arterial occlusive pathology that can lead to stroke. Stroke is a significant cause of morbidity, mortality, and loss of physical mobility. A large portion of ischemic strokes is due to carotid atherosclerotic plaque; therefore, early detection of carotid disease is central to minimizing stroke incidence. Since auscultation for a carotid bruit is non-invasive, it has been routinely performed during physical exams, especially in patients deemed high risk for cerebrovascular diseases, such as the elderly. This activity addresses interprofessional strategies for evaluating and potentially treating clinically significant carotid bruits.
Objectives:
- Identify the etiology and epidemiology of carotid bruit.
- Assess the evaluation of carotid bruit.
- Evaluate the treatment and management options available for a carotid bruit.
- Communicate interprofessional team strategies for improving care coordination for evaluating a carotid bruit to improve outcomes.
Introduction
A carotid bruit is a vascular sound usually heard with a stethoscope over the carotid artery because of turbulent, non-laminar blood flow through a stenotic area. A carotid bruit may point to an underlying arterial occlusive pathology that can lead to stroke.[1] Stroke is a significant cause of morbidity, mortality, and loss of physical mobility.[2] A large portion of ischemic strokes is due to carotid atherosclerotic plaque; therefore, early detection of carotid disease is central to minimizing the incidence of stroke.[3][4] Since auscultation for a carotid bruit is non-invasive, it has been routinely performed during physical exams, especially in patients deemed high risk for cerebrovascular diseases, such as the elderly.[5]
Etiology
Atherosclerotic lesions are commonly found in the arteries that arise from the aortic arch vessels. About 80% of these lesions are located at the bifurcation of the common carotid arteries.[1] Carotid artery auscultation is primarily done during an exam to determine if carotid stenosis may predispose the patient to a stroke. In patients with a 2 mm carotid artery luminal narrowing, carotid bruit is present 70% to 89% of the time.[6] However, luminal narrowing of the carotid artery is not the only cause of carotid bruit. Auscultatory sounds from cardiac valvular murmurs that radiate to the neck, cervical venous hums, and intracranial arteriovenous malformations can produce vascular sounds similar to the carotid bruit.[1] Arterial tortuosity, kinking, and high output clinical states may generate bruit even in normal or non-stenotic arteries. For example, in patients with thyrotoxicosis, there is a 5-to 10-fold increase in blood flow to the enlarged thyroid gland, resulting in a systolic bruit directly over the gland.[1] A case of bovine-type aortic arch and compression of the kissing carotid arteries by a retrosternal goiter is also a rare cause of a carotid bruit.[7]
Vascular occlusions from extrinsic compression, such as carotid body tumors and carotid paraganglioma, have also been reported to cause carotid bruit.[1][8][9] Disruption of the blood vessels can cause bruit and has presented in patients having a carotid artery dissection.[10] Reports of carotid bruit from inflammation of the carotid vessel due to inflammatory conditions like Takayasu arteritis are also in the literature.[11] Non-sclerotic and noninflammatory diseases such as fibromuscular dysplasia commonly affect the internal carotid arteries and cause carotid bruit. These can be found incidentally during the exam. Cervical fibromuscular dysplasia is mostly asymptomatic.[12]
Epidemiology
A carotid bruit is a nonspecific finding with a broad sensitivity described in the literature (24 to 84%).[13] It is present in about 5% of patients aged 45 to 80 years without clinically significant internal carotid disease.[6] Only about one-third of patients with carotid bruit are found to have lesions considered hemodynamically significant 70% to 90% stenosis). In patients with hemodynamically significant carotid narrowing, 50% will be found to have a bruit during carotid auscultation.[3] A carotid bruit can also be present in 20% of healthy children under 15. Nearly 22% of patients diagnosed with cervical fibromuscular dysplasia are found to have carotid bruits, although patients are seldom found to be symptomatic.[14]
Pathophysiology
The bruit typically implies stenosis at or proximal to the area of auscultation. The auscultated sound is usually the result of turbulent, non-laminar blood flow through a stenotic area. The turbulent flow creates vibrations in the arterial wall that transmit to the body surface, where stethoscopic auscultation is possible. Critical stenosis, however, does not occur until the cross-sectional area decreases to 70%, corresponding to a reduction of lumen diameter by half. Kurtz previously described the basic science of bruits: “ As stenosis increases, therefore, potential energy (pressure) proximal to the stenosis changes to increasing kinetic energy (velocity) within the stenosis. With increasing flow velocity, laminar flow through stenosis eventually changes to turbulent flow, producing vibrations and a bruit. Thus, velocity through the stenotic segment and the subsequent character of the bruit depend on the degree of stenosis and the resulting pressure gradient.” Kurtz further explained that the auscultatory quality and timing of the bruit changes with the degree of stenosis and pressure gradients. A soft early systolic murmur is audible when the lumen is about 50% narrowed. This sound can become high-pitched, more intense, and holosystolic when the stenosis approaches 60%. When the diameter reduces to 70%-80%, a bruit can be audible during systole and early diastole. As the occlusion worsens, blood flow turbulence becomes insufficient to cause vibratory sounds, and a bruit may disappear.[1]
Histopathology
A bruit from carotid artery stenosis is due to a carotid atherosclerotic plaque that can be both stable and unstable. These plaques are similar to the other arterial plaques of the body. The genesis of atherosclerosis begins with low-density lipoprotein particles trapped in the subintimal space by glycoproteins. After the low-density lipoprotein particles oxidize, a cascade of inflammatory response ensues, forming solid crystalline cholesterol that expands in volume, compromising the fibrous cap. The fibrous cap maintains the integrity of the plaques and faces the vascular lumen. Rupture of the fibrous cap leads to thrombosis, potential arterial lumen blockage, and distal embolization. High-grade carotid stenosis is often found to have inflammatory cell infiltrates. Additionally, intraplaque hemorrhage has been found in symptomatic patients and is predictive of future neurologic events and plaque rupture. Several factors seem to influence plaque morphology. Smoking may play a role in expediting atherogenesis. Men are also found to have high-risk plaque features compared to women. Interestingly, age did now show a trend toward age-related plaque instability.[4]
History and Physical
Assessing patients for risks of cerebrovascular events starts by taking a careful history and a focused physical exam. The optimum position for listening for a carotid bruit is supine or sitting with the patient. In the sitting position, optimal carotid palpation and auscultation are achievable when approaching the patient from behind. With the patient’s chin pointing straight forward, the stethoscope bell is applied over each carotid artery, sealing the overlying skin. The patient is then instructed to be inspired deeply and hold their breath without bearing down for 15 to 30 seconds. Auscultation continues during, and shortly after, the breath-holding. Breath-holding not only eliminates other adventitious sounds but also accentuates a carotid bruit.[1]
Evaluation
While a carotid bruit may alert clinicians to carotid artery disease, it is not sensitive and specific enough to diagnose carotid disease.[15] On identification of a bruit, however, the next step is to determine whether the patient needs additional testing or referral; this usually depends upon the assessed vascular risk factors of the patient or the presence of signs and symptoms suggestive of any neuro-vascular disease. Imaging studies such as carotid duplex ultrasound, computed tomography angiography, and magnetic resonance angiography of the neck help confirm the diagnosis and provide an anatomical layout if a surgical invention is warranted.[16] Collaboration with specialists like neurologists and cardiologists is also commonly employed.
Treatment / Management
Upon confirmation of carotid artery disease as the source of the carotid bruit, medical and surgical treatment should begin based on the severity of the stenosis, the presence or absence of neurological symptoms, and the patient's comorbidities.
Differential Diagnosis
Differential diagnosis for carotid bruit includes:
- Cardiac valvular murmurs
- Carotid artery vasculitis
- Carotid body tumors
- Carotid dissection
- Carotid stenosis
- Cervical fibromuscular dysplasia
- Cervical venous hum
- Extrinsic compression of the carotid artery
- High-output clinical states like thyrotoxicosis
- Intracranial arteriovenous malformations
Prognosis
While carotid bruits have generally been regarded as markers of generalized atherosclerosis, the data does not show them as strong predictors of cerebrovascular events. However, carotid bruit auscultation may help select patients who benefit the most from aggressive cardiovascular risk stratification and therapeutic interventions.[17]
Complications
The annual incidence of cerebrovascular accidents in people with asymptomatic bruits is about 1 to 3 percent.[3] Stroke is the second most common cause of mortality worldwide and the third leading cause of death in the United States. Carotid artery disease contributes to 15 to 20% of all ischemic strokes.[4]
Consultations
Consultations that are typically requested for people with carotid bruit include the following:
- Neurology
- Vascular surgery
- Cardiology
Deterrence and Patient Education
Patients must understand that while bruit itself is not a strong predictor of cerebrovascular disease, it points to the need for aggressive lifestyle modifications and therapeutic interventions. The clinician needs to tailor these measures individually to each patient and stress the importance of compliance.
Pearls and Other Issues
Asymptomatic carotid bruits are not infrequent, and their prevalence increases with age. However, this physical finding has very low accuracy, and carotid bruit alone cannot rule out or rule in carotid artery disease.[18] However, if sensibly incorporated into the patient's clinical assessment and risk stratification, it remains a viable tool in identifying patients at risk for a neurovascular event.
Enhancing Healthcare Team Outcomes
Carotid can be a significant clue to underlying carotid artery disease. Clear lines of communication between the patient and the treatment team are important in expediting referrals and subsequent additional testing to exclude carotid artery disease and promptly institute measures to mitigate the chance of stroke. While advanced imaging modalities such as carotid ultrasounds are more ubiquitous than ever, carotid auscultation as part of the physical examination is easy, cost-effective, and non-invasive. These can be compelling reasons to continue including carotid auscultation as part of a routine physical examination, especially in patients at risk for cerebrovascular disease. Primary care providers should routinely evaluate at-risk patients for carotid bruits. Physicians, nurse practitioners, and physician assistants evaluate this finding. Nurses assist in patient education, facilitate evaluation, and provide feedback to the team. Pharmacists can assist in selecting cardiovascular drug agents and monitoring for interactions. This type of interprofessional team approach to these patients can improve the odds of successful outcomes.
Review Questions
References
- 1.
- Kurtz KJ. Bruits and Hums of the Head and Neck. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd ed. Butterworths; Boston: 1990. [PubMed: 21250132]
- 2.
- Shorr RI, Johnson KC, Wan JY, Sutton-Tyrrell K, Pahor M, Bailey JE, Applegate WB. The prognostic significance of asymptomatic carotid bruits in the elderly. J Gen Intern Med. 1998 Feb;13(2):86-90. [PMC free article: PMC1496903] [PubMed: 9502367]
- 3.
- Louridas G, Junaid A. Management of carotid artery stenosis. Update for family physicians. Can Fam Physician. 2005 Jul;51(7):984-9. [PMC free article: PMC1479527] [PubMed: 16060177]
- 4.
- Mughal MM, Khan MK, DeMarco JK, Majid A, Shamoun F, Abela GS. Symptomatic and asymptomatic carotid artery plaque. Expert Rev Cardiovasc Ther. 2011 Oct;9(10):1315-30. [PMC free article: PMC3243497] [PubMed: 21985544]
- 5.
- Aronson L, Landefeld CS. Examining older people for carotid bruits: listen to your patient, not her neck. J Gen Intern Med. 1998 Feb;13(2):140-1. [PMC free article: PMC1496909] [PubMed: 9502377]
- 6.
- Grotta JC. Clinical practice. Carotid stenosis. N Engl J Med. 2013 Sep 19;369(12):1143-50. [PubMed: 24047063]
- 7.
- Aykan AÇ, Karadeniz A, Çavuşoğlu İG. Case Image: Bovine-type aortic arch and compression of the kissing carotid arteries by a retrosternal goiter: An uncommon cause of carotid bruit. Turk Kardiyol Dern Ars. 2018 Mar;46(2):165. [PubMed: 29512622]
- 8.
- Anand J, Singh JP. Bilateral sporadic carotid body tumors-A rare case report. Radiol Case Rep. 2018 Oct;13(5):988-992. [PMC free article: PMC6091435] [PubMed: 30116460]
- 9.
- Peric B, Marinsek ZP, Skrbinc B, Music M, Zagar I, Hocevar M. A patient with a painless neck tumour revealed as a carotid paraganglioma: a case report. World J Surg Oncol. 2014 Aug 20;12:267. [PMC free article: PMC4153909] [PubMed: 25141773]
- 10.
- Demiryoguran NS, Karcioglu O, Topacoglu H, Aksakalli S. Painless aortic dissection with bilateral carotid involvement presenting with vertigo as the chief complaint. Emerg Med J. 2006 Feb;23(2):e15. [PMC free article: PMC2564071] [PubMed: 16439729]
- 11.
- Silver M. Takayasu's Arteritis - An Unusual Cause of Stroke in a Young Patient. West J Emerg Med. 2012 Dec;13(6):484-7. [PMC free article: PMC3555585] [PubMed: 23359834]
- 12.
- Plouin PF, Perdu J, La Batide-Alanore A, Boutouyrie P, Gimenez-Roqueplo AP, Jeunemaitre X. Fibromuscular dysplasia. Orphanet J Rare Dis. 2007 Jun 07;2:28. [PMC free article: PMC1899482] [PubMed: 17555581]
- 13.
- McColgan P, Bentley P, McCarron M, Sharma P. Evaluation of the clinical utility of a carotid bruit. QJM. 2012 Dec;105(12):1171-7. [PubMed: 22886230]
- 14.
- Olin JW, Froehlich J, Gu X, Bacharach JM, Eagle K, Gray BH, Jaff MR, Kim ES, Mace P, Matsumoto AH, McBane RD, Kline-Rogers E, White CJ, Gornik HL. The United States Registry for Fibromuscular Dysplasia: results in the first 447 patients. Circulation. 2012 Jun 26;125(25):3182-90. [PubMed: 22615343]
- 15.
- van der Worp HB, van Gijn J. Clinical practice. Acute ischemic stroke. N Engl J Med. 2007 Aug 09;357(6):572-9. [PubMed: 17687132]
- 16.
- Qaja E, Tadi P, Theetha Kariyanna P. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Feb 12, 2024. Symptomatic Carotid Artery Stenosis. [PubMed: 28723054]
- 17.
- Pickett CA, Jackson JL, Hemann BA, Atwood JE. Carotid bruits as a prognostic indicator of cardiovascular death and myocardial infarction: a meta-analysis. Lancet. 2008 May 10;371(9624):1587-94. [PubMed: 18468542]
- 18.
- Sauvé JS, Laupacis A, Ostbye T, Feagan B, Sackett DL. The rational clinical examination. Does this patient have a clinically important carotid bruit? JAMA. 1993 Dec 15;270(23):2843-5. [PubMed: 8133624]
Disclosure: Alan Lucerna declares no relevant financial relationships with ineligible companies.
Disclosure: James Espinosa declares no relevant financial relationships with ineligible companies.
- Continuing Education Activity
- Introduction
- Etiology
- Epidemiology
- Pathophysiology
- Histopathology
- History and Physical
- Evaluation
- Treatment / Management
- Differential Diagnosis
- Prognosis
- Complications
- Consultations
- Deterrence and Patient Education
- Pearls and Other Issues
- Enhancing Healthcare Team Outcomes
- Review Questions
- References
- Review Bruits and Hums of the Head and Neck.[Clinical Methods: The History,...]Review Bruits and Hums of the Head and Neck.Kurtz KJ. Clinical Methods: The History, Physical, and Laboratory Examinations. 1990
- [Early detection of asymptomatic carotid disease in patients with obliterative arteriosclerosis of the lower extremities].[Srp Arh Celok Lek. 2002][Early detection of asymptomatic carotid disease in patients with obliterative arteriosclerosis of the lower extremities].Rancić Z, Radak D, Stojanović D. Srp Arh Celok Lek. 2002 Jul-Aug; 130(7-8):258-64.
- Symptomatic carotid ischaemic events: safest and most cost effective way of selecting patients for angiography, before carotid endarterectomy.[BMJ. 1990]Symptomatic carotid ischaemic events: safest and most cost effective way of selecting patients for angiography, before carotid endarterectomy.Hankey GJ, Warlow CP. BMJ. 1990 Jun 9; 300(6738):1485-91.
- [The significance of a carotid bruit. The preliminary experience of the OPI program. The Obiettivo prevenzione ictus (Stroke Prevention Objective)].[Minerva Cardioangiol. 1994][The significance of a carotid bruit. The preliminary experience of the OPI program. The Obiettivo prevenzione ictus (Stroke Prevention Objective)].Ghilardi G. Minerva Cardioangiol. 1994 Jun; 42(6):269-73.
- Review Circulating adiponectin levels in relation to carotid atherosclerotic plaque presence, ischemic stroke risk, and mortality: A systematic review and meta-analyses.[Metabolism. 2017]Review Circulating adiponectin levels in relation to carotid atherosclerotic plaque presence, ischemic stroke risk, and mortality: A systematic review and meta-analyses.Gorgui J, Gasbarrino K, Georgakis MK, Karalexi MA, Nauche B, Petridou ET, Daskalopoulou SS. Metabolism. 2017 Apr; 69:51-66. Epub 2017 Jan 6.
- Carotid Bruit - StatPearlsCarotid Bruit - StatPearls
Your browsing activity is empty.
Activity recording is turned off.
See more...