Carotid Bruit

Aka: Carotid Bruit

1. See Also
   1. Carotid Stenosis
2. Exam
   1. See Bruit
   2. Findings in which Carotid Bruit is more suggestive of significant carotid lesion
      1. Diastolic component is the only characteristic reliably specific for significant Carotid Bruit
      2. Carotid Bruit AND symptoms suggestive of Carotid Stenosis
   3. Degree of stenosis by atherosclerotic Plaque
      1. Minimum stenosis causing bruit: 50% (<3 mm lumen)
      2. Prolonged, high-pitched bruit: >75% (1.5 mm lumen)
   4. Location
      1. Plaque involves posterior wall of common carotid
      2. Affects bifurcation and flow into internal carotid
      3. Risk of distal thrombus formation in internal carotid
3. Differential Diagnosis
   1. Carotid Stenosis
   2. Cardiac Murmur transmission
   3. External Carotid Stenosis
   4. Venous Hum
   5. Tortuous Arteries
4. Interpretation
   1. Carotid Bruit associated risk of stroke at 1 year
   2. Asymptomatic Carotid Bruit: 1% risk at 1 year
   3. Transient Ischemic Attack history: 1.7% risk
   4. Other studies question bruit significance
5. Efficacy
   1. Carotid Bruit has poor efficacy
   2. Test Sensitivity: 40% for those with >50% Carotid Stenosis
   3. False Positives: 10% with Carotid Bruits have <50% Carotid Stenosis
6. References
   1. Brown (2017) Stroke and Cerebrovascular Disease Update, Mayo Clinical Reviews, Rochester
   2. Firnhaber (2022) Am Fam Physician 105(1): 65-72 [PubMed]