A carotid bruit is an audible “whooshing” or “blowing” sound a healthcare professional might detect with a stethoscope over the carotid arteries in the neck. This sound indicates turbulent blood flow within the artery, not a disease itself. Its detection during a physical examination often prompts further investigation.
Understanding Carotid Bruits
The “whooshing” sound of a carotid bruit occurs when blood flow becomes disorganized and choppy, rather than flowing smoothly. Under normal conditions, blood travels quietly through vessels. This turbulence, often caused by an obstruction or narrowing, creates vibrations that produce the sound. The carotid arteries, located on each side of the neck, supply oxygen-rich blood to the brain, face, and neck.
Primary Causes of Carotid Bruits
The most frequent cause of a carotid bruit is atherosclerosis, leading to carotid artery stenosis. Atherosclerosis involves plaque buildup—composed of fatty materials, cholesterol, and cellular debris—on the inner artery walls, which gradually narrows the artery’s internal space. As the artery narrows, blood flow through the constricted area becomes turbulent, generating the whooshing sound and impeding oxygenated blood supply to the brain. A carotid bruit is often present when artery narrowing reaches a significant degree, sometimes exceeding 50% stenosis.
Less Common and Benign Causes
While atherosclerosis is a common cause, other factors can also lead to carotid bruits. Conditions that increase blood flow speed can create turbulence in healthy arteries. For example, anemia (which reduces blood viscosity) or hyperthyroidism (which increases overall metabolic activity) can both result in bruits. Anatomical variations, like tortuous or kinked carotid arteries, can also disrupt smooth blood flow, and sounds from heart valve conditions, like murmurs, can sometimes radiate to the neck and be mistaken for a bruit. Not all bruits indicate severe underlying disease; “innocent” or “benign” bruits are common in children and young adults, often stemming from naturally higher blood flow velocities, and typically do not signal a serious medical concern.
Significance and Further Evaluation
Detecting a carotid bruit is important as it can be a warning sign, particularly for carotid artery disease, which increases stroke risk. However, a bruit alone is not a definitive diagnosis of artery narrowing; it indicates the need for further assessment. When a bruit is heard, a healthcare provider typically recommends additional diagnostic tests, with the most common initial test being a carotid duplex ultrasound. This non-invasive procedure uses sound waves to image the carotid arteries, allowing visualization of artery walls, assessment of blood flow, and determination of any narrowing or blockages, which then guides management decisions.