Anatomy is the key to the differential diagnosis of a cervical bruit. Visualizing the neck, we have the carotid, innominate, and subclavian arteries; the jugular, innominate, and subclavian veins; the thyroid, scalenus anticus muscle, and cervical ribs, all of which may be involved in this sign.
· Arteries. This should prompt the recall of a carotid or subclavian artery stenosis (subclavian steal syndrome) or an aneurysm. It should also remind us of aortic murmurs that may be transmitted to the neck from a stenosed aortic valve, calcific aortitis, or an aortic aneurysm.
· Veins. A venous hum may be heard in the neck as a result of a circuitous route that blood must take in the veins. This is of course usually benign.
· Thyroid. This prompts the recall of the bruit heard over the thyroid in Grave disease.
· Muscles. Occasionally a bruit is heard in the neck in patients with scalenus anticus syndrome or other forms of thoracic outlet syndrome.
· Cervical rib. The subclavian artery may also be compressed by a cervical rib producing a cervical bruit.
Approach to the Diagnosis
A history of diaphoresis, weight loss, or heat intolerance would arouse suspicion of hyperthyroidism. A history of transient hemiplegia, amaurosis fugax, or other intermittent neurologic symptomatology should point to a carotid stenosis or subclavian steal syndrome. Physical findings of pallor or spoon nails would point to anemia. An enlarged thyroid prompts the suspicion of hyperthyroidism. If there's a diminished pulse on the side of the bruit, look for thoracic outlet syndrome or subclavian steal syndrome. The diagnostic workup may need to include a CBC, thyroid panel, and carotid duplex scan.
Consult a neurologist if there are objective neurologic signs. Four-vessel angiography needs to be considered if a carotid stenosis or subclavian steal syndrome is suspected. If the bruit seems to be transmitted from the chest, echocardiography may be needed.