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High blood
pressure or hypertension means high pressure or
tension in the arteries. An elevation of the
systolic and/or diastolic blood pressure
increases the risk of developing cardiac
disease, renal disease, hardening of the
arteries, eye damage, and brain damage. These
complications of hypertension are often referred
to as end-organ damage because damage to these
organs is the end result of chronic (long
duration) high blood pressure.
Primary hypertension
Patients in whom
no specific cause for hypertension is detected
are labeled as primary 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 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.
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