How are stroke and heart disease related?
Stroke is often due to sudden loss of blood supply to a region of the brain which usually results in paralysis of a part of the body. Stroke could also be due to bleeding into a part of the brain. Strokes and heart disease are linked together in various ways. In general, risk factors for stroke and some forms of heart disease are similar. Strokes due to blocks in blood vessels, can be seen along with blocks in blood vessels of the heart. Stroke can occur after a heart attack as well. Heart attack damages a part of the heart muscle. This can lead to damage of the inner lining of the heart in that region. A blood clot can form on the inner surface of the heart as a consequence. These clots can break away into the circulation and get lodged into a blood vessel of the brain. The clot thus blocks a blood vessel of the brain and causes stroke.
Another type of heart disease which leads to stroke is an abnormal rhythm of the heart known as atrial fibrillation. In atrial fibrillation, there is a fast irregular rhythm originating in the upper chambers of the heart. The rhythm is so fast that effective contractions of the upper chambers cease. This leads to stagnation of blood in certain parts of the left atrium (upper chamber of the heart), where a blood clot can form. These clots can also get dislodged and travel to blood vessels of the brain. They in turn block a blood vessel of the brain and cause stroke.
Another reason for stroke is high blood pressure. When the blood pressure goes very high suddenly, small blood vessels in the brain may break leading to a bleed into the brain matter. This form of stroke (hemorrhagic stroke) is generally more dangerous than a stroke due to blockage of a blood vessel. Even without a bleed, brain function can be altered due to high blood pressure, causing alteration in the level of consciousness. But then that is not a stroke, but called as hypertensive encephalopathy (brain disease due to high blood pressure).
What is high blood pressure?
Normal pressure in the main blood vessels arising from the heart is below 120/80 mm Hg. The higher value occurs when the heart contracts and pumps blood and is known as systolic blood pressure. The lower value occurs when the heart relaxes. When the blood pressure is above 140/90 mm Hg, it is usually called high blood pressure (hypertension). Blood pressure varies with age – it is low in a new born baby and rises as the age increases. The values mentioned above are for adults above the age of 18 years. In younger individuals, we have to check with normal blood pressure chart for each age as it is difficult to memorize the values for each age.
What are the symptoms of high blood pressure?
Very often there are no symptoms for high blood pressure and a good number of individuals who have high blood pressure do not know it. High blood pressure is detected during evaluation for other illnesses. Headache, though an important symptom of high blood pressure, is most often due to other causes. Dizziness is another symptom which could occur with high blood pressure. Sometimes an individual comes with symptoms due to complications of high blood pressure rather than due high blood pressure itself.
What are the important complications of high blood pressure?
When the blood pressure goes up very high at a very fast rate, it cause rupture of a blood vessel. This typically occurs in the brain causing bleeding into the brain (cerebral hemorrhage). If a large portion of the brain is damaged due to rapid bleeding, it can lead to sudden death. Otherwise the person gets a bleeding stroke (hemorrhagic stroke), which often manifests with weakness of one side of the body with our without loss of consciousness or difficulty in speaking. High blood pressure can damage the heart, kidneys and the eyes. In the heart it can lead to heart attack and heart failure. Kidneys may fail due to high blood pressure (renal failure). Bleeding into the layers of the eye can occur due to high blood pressure. For that matter, high blood pressure can damage the blood vessels in any part of the body.
What causes high blood pressure?
The most common cause of high blood pressure in adults is unknown and it is called essential hypertension. Other causes of high blood pressure are known as secondary hypertension. Kidney disease, certain hormone disorders, obstruction to blood vessels, diseases of blood vessels and even undue anxiety and stress can cause high blood pressure. Secondary causes are more likely in younger individuals.