In
most cases of high blood pressure (hypertension),
there is no known cause. About 5 percent of the
time, however, hypertension is caused by another
condition or disease. When this happens, it is called
secondary hypertension.
Secondary hypertension can be caused
by a number of different conditions. The main causes
are listed below.
Kidney problems
Kidneys are important in the regulation of blood
pressure, and kidney problems account for a large
share of secondary hypertension. Damaged kidneys
also may release hormones and other chemicals that
raise your blood pressure.
Obstruction of the renal artery
Obstruction of the renal artery, the main vessel
supplying each kidney, also causes secondary hypertension.
The obstruction is most often due to atherosclerosis,
narrowing of the blood vessel due to a buildup of
fatty deposits on and under the lining of the artery
wall.
Coarctation of the aorta
This is a narrowing of the primary blood vessel
supplying blood from your heart to your body. Coarctation
usually occurs in the portion of the aorta in your
chest and rarely in your abdomen.
Pheochromocytoma
This is a tumor of the inner layer of your adrenal
gland (medulla). These tumors, which can also occur
in other parts of your body and can be in multiple
locations, secrete the hormones epinephrine and
norepinephrine as well as other chemicals.
Pheochromocytoma almost always causes
prominent symptoms and physical findings. If you
have one of these types of tumors you may experience
spells of sudden severe headache, palpitations and
profuse perspiration, during which time you appear
pale. These spells may last minutes to an hour and
recur daily or very infrequently. Your blood pressure
is almost always markedly elevated during the spell,
and you may have elevated blood pressure between
spells.
Thyroid dysfunction —
both overactive and underactive
Overproduction of thyroid hormone is called hyperthyroidism
and may elevate your systolic blood pressure and
heart rate.
Underproduction of thyroid hormone,
or hypothyroidism, also can cause high blood pressure
— both systolic and diastolic.
Cushing's syndrome and aldosteronism
These disorders are due to hormones produced by
the outer layer (cortex) of the adrenal gland.
Medications
A number of drugs can increase blood pressure in
some people.
When you are being evaluated for high
blood pressure, it's important to always list any
prescribed medications, over-the-counter medications
and herbal compounds you are currently taking.
Sleep apnea
Obstructive sleep apnea is a severe form of snoring
that interrupts your breathing while you sleep.
(Adapted from Mayo Clinic)
Testing for Secondary Causes of
Hypertension
The following table lists the various
tests used to confirm secondary high blood pressure
and clarify its causes. Your doctor may use one
or more of these tests for each condition depending
on your individual situation.
Secondary cause
Reasons to suspect
Test used to evaluate
Narrowing
of the aorta (the artery that carries blood from your
heart to the rest of your body)
High blood
pressure accompanied by low pulse in the legs
Imaging of the aorta by one of the following:
Ultrasound
Magnetic resonance
angiography (MRA)
Angiogram
Hardening or narrowing
of the arteries in your kidneys (renal artery stenosis)
High blood
pressure at young age, particularly in women.
Severe problems with your blood vessels in other parts
of your body
A test that clearly shows the structure of your
renal arteries:
:Renal arteriogram
MRA
Hormonal
imbalances
Diabetes, obesity in
the middle of your body,facial swelling, acne
Blood tests
that show your hormone levels
Excess production of
the hormone aldosterone, which regulates the salt
and water balance in your kidneys
Low levels
of potassium in your blood
Blood tests
that show your hormone and potassium levels
A tumor in your adrenal
glands (located just above your kidneys)
Headaches,
fluttering in your heart, flushing, unstable blood
pressure
Specific blood (hormone) and urine tests
Specialized imaging studies.
High blood pressure caused
by a new medication
You are
taking a new medication
Review of
your medication list
Reevaluation of blood pressure when suspected agent
is discontinued
High blood
pressure caused by alcohol or cocaine .
You use
cocaine or excessive alcohol.
Re-evaluation of blood
pressure when suspected agent is discontinued
