The carotid arteries are parallel blood vessels in both sides of the neck that supply blood to the head and brain. The internal carotid arteries run along the neck to the brain, while the external carotid arteries carry blood to the face. Diseases of the carotid arteries, such as atherosclerosis, can cause blockages that prevent the flow of blood to the brain and head. The Texas Heart Institute underlines that blockages of carotid arteries often go unnoticed until serious side effects of this disease occur. These include transient ischemic attacks or "mini-strokes" and strokes that can cause several noticeable effects.
If a blockage in the carotid artery affects the flow of blood to parts of the brain that control sight, loss or damage to vision may occur. The Mayo Clinic warns that vision side effects of a carotid artery blockage can occur suddenly and often only affect one eye.
Ischemia is a decreased flow of blood to the cells. If the cells in the brain are deprived of adequate oxygen and nutrients due to a carotid artery blockage, they can become damaged. The Mayo Clinic notes that this causes severe headache pain as well as nausea, vomiting, a stiff neck and in some cases loss of consciousness.
Confusion and Dizziness
Carotid artery blockages can also lead to confusion, loss of short-term memory and dizziness. The Mayo Clinic notes that this side effect is most noticeable when it causes the patient's speech to become slurred or incoherent or if they stop in the middle of a sentence. Some individuals may be unable to speak. Dizziness may be so severe that the patient is unable to stand or walk.
A carotid artery blockage can impede blood flow to areas of the brain that control skeletal muscle motor function. This side effect can cause paralysis, weakness, tingling or numbness in areas of the body, as listed by the Texas Heart Institute. In cases of early signs of a carotid blockage and a transient ischemic attack, these side effects are usually temporary and the patient regains full muscle control and strength. However, if the blockage in the carotid artery is severe, permanent damage and paralysis in areas of the body can occur. In most patients a stroke affects one side of the body.