Hypertension ( High Blood Pressure )

Hypertension or high blood pressure is probably the most important public health problem in developed countries. It is very common, generally doesn’t produce very prominent symptoms especially in the early stages.

The good thing is, High blood pressure is easily detected and usually easily treatable. On the other hand, leaving it untreated can lead to a host of problems like heart disease, kidney failure or stroke etc. and may even prove fatal.

How is Blood Pressure measured and denoted?
It is usually measured with a blood pressure cuff placed around the arm, which registers the pressure in units called millimeters of Mercury. Blood pressure or BP is denoted by two numbers separated by aslash (/) for example, a reading of 120/80 would mean that 120 millimeters of mercury is the systolic pressure and 80 millimeters of mercury is the diastolic pressure.

Systolic blood pressure, the top number, represents the pressure in our arteries as the heart contracts and ejects blood into the circulation. Diastolic pressure, the bottom number, occurs as the heart relaxes following a contraction. It represents the minimum pressure to which the arteries are exposed.

How high is a ‘High Blood Pressure’?
Strictly speaking no single reading of blood pressure has been identified as to mean hypertension, but it is generally accepted that a value of 140/90 or more taken on at least two separate occasions, indicates a high blood pressure. This is the level above which there is a significantly higher risk of heart and kidney disease as well as hardening of the arteries (arteriosclerosis), which can lead to stroke. High blood pressure accelerates the process that leads to hardening of the arteries.

What causes high blood pressure?
Primary hypertension:
Patients in whom no specific cause for hypertension is detected are labeled

as primary hypertension. Unfortunately despite intensive research, the cause of hypertension is not found in a vast majority of cases. In fact no specific cause is found in almost 95% of patients with hypertension. The vast majority of cases of primary hypertension are due to increased stiffness (resistance) of the peripheral arteries. Increased peripheral artery resistance is associated with:

• Heredity: Genetic factors are considered to very important in the development of hypertension. Hypertension often runs in families.
• Environmental factors: like increased salt intake, obesity, lack of exercise, etc. are also considered responsible.

Secondary hypertension:
Cases of hypertension where some specific cause can be found are termed as secondary hypertension. Though accounting for only 5% of cases of hypertension, these are important because correction of the cause can often lead to cure of hypertension. Following are some of the most common causes of secondary hypertension:

• Kidney disease: In chronic kidney disease, excessive fluid accumulation in the body elevates blood pressure.
  Narrowing (stenosis) of the artery to the kidney is an uncommon condition that typically causes sudden, severe hypertension. The majority (66%) of kidney artery narrowing is caused by hardening of the arteries (atherosclerosis), usually in older men. The remaining 33% is caused by the thickening (fibroplasia) of the muscular wall of the arteries to the kidneys, usually in younger women. Reduction of blood supply to the kidneys causes production of the hormone renin, which acts to constrict the arteries, thereby elevating blood pressure.
  
  
• Oral contraceptive pills: the pills containing the hormone Estrogen may lead to hypertension and some experts believe that it may be the most common cause of secondary hypertension.
  
  
• Other causes: these include tumors of the pituitary or the adrenal glands.

What does a patient feel with elevated blood pressure?
Uncomplicated high blood pressure usually occurs without any symptoms and has therefore been labeled "the silent killer." This condition can be present for a long time , causing progressive unnoticed heart and blood vessel disease, before it is recognized. It is a common myth that people suffering from high blood pressure have symptoms like headache or are quick to anger. While symptoms such as headache, dizziness and blurred vision can occur, they are rare.

About 1% of patients first visit the doctor with severe high blood pressure (accelerated or malignant hypertension). In these patients, diastolic blood pressure exceeds 140 and is associated with headache, nausea, and dizziness. Accelerated or malignant hypertension requires urgent medical treatment in the hospital to prevent stroke or brain hemorrhage.

What are the effects of high blood pressure? | How is high blood pressure treated?
Drugs | Diuretics | Things to Remember