What happens when the carotid artery is blocked?

Because the carotid arteries deliver blood to the brain, carotid artery disease can have serious implications by reducing the flow of oxygen and nutrients to the brain. The brain needs a constant supply of oxygen and nutrients in order to function. Even a brief interruption in blood supply can cause problems. Brain cells begin to die after just a few minutes without blood or oxygen. If the narrowing of the carotid arteries becomes severe enough to block blood flow, or a piece of atherosclerotic plaque breaks off and obstructs blood flow to the brain, a stroke may occur.

A narrowing, hardening, or irregularity of the carotid artery can cause a blood clot or accumulation of debris to form in the artery. This is known as carotid artery disease. The debris may break off into the blood stream and interfere with blood flow to the eyes and brain. A reduction of blood flow through one of the carotid arteries may cause temporary vision loss in the eye on the same side. The loss of vision is like a curtain being drawn over the eye and usually lasts just one or two minutes. Weakness or numbness can also occur on one side of the body.

Temporary blockages of the arteries are called transient ischemic attacks (tia). You should see your ophthalmologist (Eye M.D.) or physician immediately if you experience such episodes. TIAs are warning signs that a complete blockage of the artery may occur.

A complete blockage of the carotid artery can cause a stroke. The effects of stroke can be either mild (loss of side vision or slight muscle weakness) or severe (complete loss of vision, paralysis of one side of the body, loss of speech).

During a carotid artery block, the blood flow to the brain is reduced or cut off. This may result in a stroke.

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