Carotid artery stenosis | |
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Classification and external resources | |
Specialty | cardiology |
ICD-10 | I65.2 |
ICD-9-CM | 433.1 |
DiseasesDB | 31178 |
MedlinePlus | 007427 |
MeSH | D016893 |
Carotid stenosis is a narrowing or constriction of the inner surface (lumen) of the carotid artery, usually caused by atherosclerosis.
The carotid artery is the large artery whose pulse can be felt on both sides of the neck under the jaw. On the right side it starts from the brachiocephalic trunk (a branch of the aorta) as the common carotid artery, and on the left side the common carotid artery comes directly off the aortic arch. At the throat it forks into the internal and external carotid arteries. The internal carotid artery supplies the brain, and the external carotid artery supplies the face. This fork is a common site for atherosclerosis, an inflammatory buildup of atheromatous plaque that can narrow the lumen of the common or internal carotid arteries.
The plaque can be stable and asymptomatic, or it can be a source of embolization. Emboli break off from the plaque and travel through the circulation to blood vessels in the brain. As the vessel gets smaller, they can lodge in the vessel wall and restrict blood flow to parts of the brain which that vessel supplies. This ischemia can either be temporary, yielding a transient ischemic attack, or permanent resulting in a thromboembolic stroke.
Clinically, risk of stroke from carotid stenosis is evaluated by the presence or absence of symptoms and the degree of stenosis on imaging.
Transient ischemic attacks (TIAs) are a warning sign, and are often followed by severe permanent strokes, particularly within the first two days. TIAs by definition last less than 24 hours and frequently take the form of a weakness or loss of sensation of a limb or the trunk on one side of the body, or the loss of sight (amaurosis fugax) in one eye. Less common symptoms are artery sounds (bruits), or ringing in the ears (tinnitus).
The carotid artery is the large vertical artery in red. The blood supply to the carotid artery starts at the arch of the aorta (bottom). The carotid artery divides into the internal carotid artery and the external carotid artery. The internal carotid artery supplies the brain. Plaque often builds up at that division, and causes a narrowing (stenosis). Pieces of plaque can break off and block the small arteries above in the brain, which causes a stroke. Plaque can also build up at the origin of the carotid artery at the aorta.