The brain, like all body systems, is highly complex and specialized. Though we don’t know everything there is to know about how the brain works, we do know that brain cells are irreplaceable. That is, whereas most cells in the body can regenerate, the individual cells which are the working units of the brain, called neurons, cannot. This is why a stroke can result in life-long effects in the affected individual.
Brain cells need oxygen and glucose (sugar) for proper function. Any prolonged disruption of the supply of either of these chemicals can lead to cell death. In a stroke, (cerebral vascular accident or CVA), the blood supply to the brain cells is cut off. In about 85 percent of cases, this disruption is due to a blockage within an artery supplying the brain. The lack of glucose and oxygen to the neurons results in cell death and loss of function in the area supplied by that artery.
The other 15 percent of strokes are hemorrhagic strokes. This means a blood vessel is damaged and there is bleeding into the brain cells. This not only disrupts the energy supply to the neurons, but can lead to excess pressure within the brain, thereby “choking out” the cells.
The brain’s neurons are departmentalized into specific locations, each region performing a specific function. Some are for movement, some for sensation, some for speech, etc. Any of the body’s functions could be affected by a stroke. For example, if the blood supply was interrupted to the area of the brain that initiates moving an arm, one would experience weakness or loss of movement in that arm.
The symptoms of a stroke will depend on where the blockage or bleeding has occurred within the brain and which specialized cells are affected. Symptoms may include: weakness, numbness or tingling in the face, an arm, or a leg; sudden, severe headache; unexplained dizziness, unstable walking or falling; loss or slurring of speech, trouble talking or understanding what others are saying; sudden dimness or loss of vision, particularly in one eye; double vision; and facial drooping.
Since most strokes are due to a blockage of blood flow, it is important to seek medical treatment immediately if you are experiencing symptoms that are suspicious for a stroke. Emergency medicines and procedures that can help to quickly restore the blood flow to the affected brain cells are available. Lost time getting emergency treatment can be the difference between a temporary loss of function and a permanent loss.
Equally important to emergency treatment of an acute stroke are the measures we can take to reduce our risk of a stroke. The major risk factors are high blood pressure, smoking, high cholesterol, and uncontrolled diabetes (high sugar). These conditions can contribute to the buildup of plaque within the blood vessels (hardening of the arteries) thus leading to a blockage; or to the weakening of the blood vessels resulting in bleeding. Individuals who have heart disease or who have had a previous mini-stroke (TIA) are at higher risk as well.
It’s important to meet with your doctor to identify your risk factors and discuss appropriate treatment if needed. If you have high blood pressure, high cholesterol, or high blood sugar, get these under control. If you smoke, take steps to quit now. Daily exercise helps to control your blood pressure, your cholesterol and your sugar. Avoid foods that are high in saturated fat and cholesterol. Eat less sodium (salt) to help lower your blood pressure.
The content in this column is for informational purposes only. Consult your physician for appropriate individual treatment. Dr. Reynolds practices Family Medicine in Chesterfield.