Hypertension is a well known condition in which there is chronic elevation of blood pressure (>140/90mm.Hg.)In majority (90 -95% of cases) it is without a known cause when it is called the primary or essential hypertension.
But in other 5% cases it is secondary to some other cause, hence called appropriately, “secondary hypertension”.
It is important to know about secondary hypertension, because in these cases, hypertension is also cured with cure of the, “ cause”.
Unless the cause is treated, hypertension will remain untreated. Kidney disorders are the most common cause for secondary hypertension.
Diseases of the kidney parenchyma or blood vessels, or glomeruli ( containing filtration units of the kidney), cause high blood pressure.
These disorders can be present since birth like congenital renal artery stenosis or they may be acquired later in life like infections or tumors of different parts of kidney.Coarctation of the aorta ( major blood vessel supplying blood to entire body from heart) is a condition in which there may be constriction of the aorta at some place near the heart or shoulders.
This becomes the cause for secondary hypertension in children or young adults. Hormonal disorders of different kinds in the body are also responsible for secondary hypertension.Tumors of the adrenal medulla produce large amount of adrenaline
in the body and elevation of blood pressure.
Similarly enlargement of the adrenal gland, hyperactivity
of the thyroid or pituitary gland, all these can cause secondary
hypertension. In the same way hormones taken in form of tablets for treatment are also responsible for secondary
Most common example is oral contraceptive pills taken by women. After few months they start developing hypertension
along with other side effects.
Another common cause for high blood pressure caused by treatment is that produced due to use of steroid tablets or injections for a long time. Hypertension developing during
pregnancy is also a type of secondary hypertension which causes much distress and suffering to mother and baby.
Secondary hypertension becomes different from primary hypertension in that any age or extremes of age may be affected.
For example a child as young as 13 or 14 years may develop high blood pressure. An elderly man of 75 years, previously normal may start having hypertension due to any of these causes.
Clinically both types of hypertension can cause headache, palpitations,feeling of restlessness, anxiety, e.t.c. due to the high pressure under which blood flows in the body.
In case of hypertension developing in an adolescent or teenager or very old person, the doctor would always probe for a cause causing secondary hypertension.
For middle aged persons it becomes difficult at times to decide
the nature of the high blood pressure.
Secondary hypertension usually remains resistant to the treatment given and this is what helps in differentiating the two.
This happens because there is an underlying cause for it waits to be corrected. If not corrected in time, secondary hypertension can lead to more severe complications and damage to target organs as compared to primary hypertension.
The affected person can develop sudden loss of vision. There may be a stroke causing paralysis of various body parts or heart attack leading to sudden cardiac arrest and death.
Chronic complications can be manifested as precipitation of kidney failure or aggravation of existing kidney failure, problems in vision previously well corrected by eye glasses, e.t.c.
To avoid these complications, a person with doubt of secondary hypertension, particularly a young adult is screened for various conditions likely to cause secondary hypertension.
Once the condition causing secondary hypertension is detected, it should be treated on top priority basis. Antihypertensive drugs are used simultaneously to keep the blood pressure under control.
The author is a specialist in Internal Medicine
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