While sounds within the human body, like a heartbeat or breathing, are typically associated with healthy function. However, a bruit is another type of sound that can be detected. These sounds offer clues about blood flow within the body’s vessels.
Understanding Bruits
A bruit (pronounced “broo-ee”) is an abnormal, blowing or whooshing sound heard over an artery or vascular channel, typically detected with a stethoscope. This sound arises from turbulent blood flow, a chaotic movement of blood within a vessel. Normally, blood flows smoothly in parallel layers, a pattern called laminar flow, moving quietly.
When blood flow becomes turbulent, it swirls and mixes, causing vibrations that generate the audible whooshing sound. Conditions that increase blood flow velocity, such as fever or anemia, can intensify the sound of a bruit. Similarly, a narrowing or obstruction within an artery can lead to localized turbulence, producing this distinct sound.
Where Bruits Occur and Their Causes
Bruits can occur in various arteries throughout the body, with specific locations often indicating particular underlying conditions. Carotid bruits, heard in the neck over the carotid arteries, are a common concern. These arteries supply blood to the brain, and a bruit here often suggests narrowing due to atherosclerosis, a plaque buildup that can restrict blood flow and increase the risk of stroke.
Abdominal bruits can also be significant. An abdominal aortic bruit might signal an abdominal aortic aneurysm, a bulging or ballooning of the body’s largest artery. Alternatively, bruits heard over the renal arteries, located on either side of the abdomen, can indicate renal artery stenosis, a narrowing that may contribute to high blood pressure. In the groin, femoral bruits over the femoral arteries often point to peripheral artery disease (PAD), where plaque buildup affects blood flow to the legs.
Beyond arterial narrowing, other conditions can cause bruits. Arteriovenous malformations (AVMs) are abnormal tangles of blood vessels where arteries connect directly to veins, bypassing the usual capillary network. The rapid, high-pressure flow of blood from arteries into veins in an AVM creates significant turbulence, leading to a prominent bruit. Certain conditions that increase overall blood flow, such as hyperthyroidism, can also result in bruits due to elevated blood velocity.
Diagnosing and Understanding the Significance of Bruits
The detection of a bruit begins with a physical examination using a stethoscope. A healthcare provider listens over various arterial locations for the characteristic whooshing sound. When checking for carotid bruits, a patient might be asked to hold their breath briefly to eliminate breathing sounds. A bruit is a physical sign, not a definitive diagnosis on its own.
While some bruits, particularly in children or in states of high blood flow like severe anemia, can be benign, many indicate an underlying vascular condition requiring further investigation. The significance of a bruit depends on its location, characteristics, and the patient’s overall health and risk factors. For example, a carotid bruit, while not always indicating severe narrowing, prompts further evaluation due to its potential link to stroke risk.
If a bruit is detected, the next step involves imaging tests to determine its cause and severity. Duplex Doppler ultrasound is a common, non-invasive first-line test, providing detailed information about blood flow and identifying areas of narrowing or plaque buildup. For a more comprehensive view, computed tomography angiography (CTA) or magnetic resonance angiography (MRA) may be used to visualize the blood vessels in detail, especially for aneurysms or complex vascular issues. These tests help healthcare providers understand the specific condition causing the bruit and guide appropriate management or treatment.