Symptoms & Warning Signs

For many people, carotid stenosis is a “silent” condition. You may have significant narrowing in your arteries and feel perfectly healthy because the brain often finds ways to compensate for slow changes ^[1]. However, when symptoms do occur, they are a critical warning that your brain is not receiving enough blood or that a piece of plaque has broken loose ^[2][3].

The Warning: Transient Ischemic Attack (TIA)

A Transient Ischemic Attack (TIA), often called a “mini-stroke,” is the most important warning sign of carotid stenosis. It occurs when blood flow to a part of the brain or eye is temporarily blocked and then restored ^[4][5].

A TIA is a medical emergency. Even if the symptoms last only a few minutes and disappear completely, the danger has not passed. In patients with significant carotid narrowing, the risk of a full, permanent stroke is highest in the immediate hours and days following a TIA, requiring urgent medical assessment ^[6][7].

• About 2.7% of patients in historical cohorts experienced a full stroke within 24 hours of their first warning sign ^[6].
• That risk climbed to over 5% within three days and nearly 19% within 90 days if left untreated ^[6].

Classic Symptoms of Carotid Disease

When the carotid artery is the source of the problem, symptoms usually affect only one side of the body or one specific eye.

Amaurosis Fugax (Vision Loss)

This is a very specific type of temporary vision loss in one eye. Patients often describe it as a dark shade or curtain being pulled down over their field of vision ^[4]. It is usually painless, occurs suddenly, and typically lasts less than an hour before vision returns to normal ^[4][8]. Because the right carotid artery supplies the right eye, this vision loss occurs on the same side as the narrowing ^[9].

Hemispheric Symptoms (Body Weakness)

Because the right side of your brain controls the left side of your body (and vice versa), a problem in the left carotid artery will cause symptoms on the right side of your body ^[10]. These include:

• Weakness or Numbness: A sudden loss of strength or a “pins and needles” feeling in your face, arm, or leg ^[10][11].
• Facial Droop: One side of your mouth may hang down or feel numb when you try to smile ^[12].

Speech and Language Difficulties

If the narrowing is in the “dominant” side of your brain (which is the left side for most right-handed people), you may experience:

• Aphasia: Difficulty finding the right words or understanding what others are saying ^[10].
• Slurred Speech: Your words may sound garbled or thick, even if you know what you want to say ^[12].

When to Call Emergency Services: The FAST/BE-FAST Criteria

If you or someone you are with experiences any of these signs, call emergency services immediately. Use the BE-FAST acronym to remember what to look for:

• B (Balance): Sudden loss of balance or coordination.
• E (Eyes): Sudden loss of vision in one or both eyes.
• F (Face): Does one side of the face droop?
• A (Arms): If they raise both arms, does one drift downward?
• S (Speech): Is their speech slurred or strange?
• T (Time): If you see any of these signs, it is time to call 911.

Do not wait to see if the symptoms go away. Do not call your primary care doctor first. Go to the nearest emergency room by ambulance immediately.

Not Typical When Isolated

It is common to worry that any neurological symptom is a sign of a carotid stroke. The following are not typical signs of a narrowing in the main extracranial carotid arteries when they happen completely on their own:

• Generalized Dizziness or Vertigo: A spinning sensation or feeling off-balance is more often related to the inner ear or the “posterior” arteries at the back of the neck ^[13][14].
• Fainting (Syncope): Passing out completely is usually a heart rhythm issue or a sudden drop in blood pressure, rather than a carotid blockage ^[15].
• Generalized Headaches: While a stroke can cause a headache, a standard migraine or tension headache is rarely the only sign of carotid stenosis ^[16].

However, these can still be emergencies. Sudden dizziness or imbalance, severe sudden headache, fainting, or visual symptoms can signal a stroke in the back of the brain (posterior circulation), a hemorrhage, an artery tear (dissection), or a cardiac emergency ^[13][15][16]. Any sudden neurological deficit requires immediate emergency medical care.