High blood pressure – Hypertension

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 BP is above 140/90 mm Hg, it is usually called high BP (hypertension). BP varies with age – it is low in a newborn 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 BP 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 BP do not know it. High BP is detected during evaluation for other illnesses. Headache, though an important symptom of high BP, is most often due to other causes. Dizziness is another symptom which could occur with high BP. Sometimes an individual comes with symptoms due to complications of high BP rather than due to high BP itself.

What are the important complications of high blood pressure?

When the blood pressure goes up very high at a very fast rate, it causes 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 or without loss of consciousness or difficulty in speaking.

High BP 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 BP (renal failure). Bleeding into the layers of the eye can occur due to high BP. 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 BP in adults is unknown and it is called essential hypertension. Other causes of high BP 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 BP. Secondary causes are more likely in younger individuals.

How is blood pressure measured?

Blood pressure is measured using a BP apparatus, which is technically known as sphygmomanometer. Conventional BP apparatus uses a mercury manometer to indicate the blood pressure. But it is being phased out due to the environmental hazards of mercury. Newer devices for use in the clinic are based on aneroid manometers, in which a dial shows the blood pressure.

Digital devices for home recordings are also widely available. They use oscillometric method of blood pressure measurement. Digital devices are also widely used in emergency departments, intensive care units and operating rooms. In these situations they are not stand alone BP apparatus, but BP measurement is one of the multiple parameters measured and displayed in these multi-parameter monitors.