This is a condition in which the blood pressure of an adult is persistently
higher than 140/90 mmHg in a non-diabetic, or above 130/80 mmHg in a
diabetic, based on the average of two or more properly measured blood
pressure readings.
Hypertension carries an increased risk of early death from stroke, heart
attack, heart failure and kidney failure if not properly controlled. Once a
diagnosis of hypertension is made, the individual should be evaluated for
the cause of the hypertension. Most adults, however, tend to have primary
hypertension.
DISORDERS OF THE CARDIOVASCULAR SYSTEM
Most patients with hypertension will require two or more
antihypertensive medications to achieve the desired target blood pressure.
The choice of medication(s) is influenced by individual patient factors such
as age, sex, cardiovascular risk, associated medical conditions and adverse
effects.
CAUSES
· Primary hypertension - In the majority of patients no specific
underlying cause is identified. Risk factors associated with this type of
hypertension include increasing age, family history, excess body weight,
excessive alcohol intake.
· Secondary hypertension - In about 10% of cases, hypertension may be
due to a kidney disease, endocrine disorder, renal artery stenosis or
coarctation of the aorta.
SYMPTOMS
· There are no complaints that are specific for hypertension. Most
patients with hypertension may have no complaint whatsoever and are
discovered by chance during medical examinations.
· Occasionally, patients may complain of:
· Headache
· Palpitation
· Dizziness
· Easy fatigability
SIGNS
· Blood pressure of >140/90 mmHg
· Signs specific for the various kidney, endocrine and blood vessel
disorders that cause secondary hypertension.
INVESTIGATIONS
· FBC
· Urinalysis
· Blood urea, electrolytes and creatinine
· Blood glucose
· Serum lipids
· Serum uric acid
· Chest X-ray
· ECG
· Ultrasound scan of kidneys and adrenals (in suspected secondary
hypertension)
DISORDERS OF THE CARDIOVASCULAR SYSTEM
TREATMENT
Treatment objectives
· To reduce blood pressure levels to 140/90 mmHg or less (130/80 mmHg
or less in diabetics)
· To prevent cardiovascular, cerebrovascular and renal complications
· To identify and manage secondary hypertension appropriately
Non-pharmacological treatment
· Reduce salt intake
· Reduce animal fat intake
· Ensure regular fruit and vegetable intake
· Weight reduction in obese and overweight individuals
· Regular exercise e.g. brisk walking for 30 minutes 3 times a week
· Reduction in alcohol consumption
· Cessation of smoking
Pharmacological treatment
(Evidence rating: B)
Table 8-1: Antihypertensive Treatment by Drug Class
Antihypertensive Class Comments
Thiazide diuretics
Bendroflumethiazide (bendrofluazide),
oral, 2.5 mg daily
Angiotensin-converting enzyme (ACE)
inhibitors
Lisinopril, oral, 5-40 mg daily
Or
Ramipril, oral, 2.5-10 mg daily
· Use with caution in gout, diabetes
mellitus and dyslipidaemia
· Enhances effectiveness of other
classes of antihypertensives when used
in combination
· Avoid in pregnancy and renovascular
diseases
· Can be used in heart failure, diabetes
nephropathy and left ventricular
dysfunction
· Commonest side effect is dry persistent
cough
· Monitor serum potassium level
periodically
Beta-blockers
Atenolol, oral, 50 -100 mg daily
Or
Bisoprolol, oral 5-20 mg daily
Or
Carvedilol, oral, 6.25-25 mg 12 hourly
· Useful in angina and post myocardial
infarction (when not
contraindicated)
· Avoid in asthma, chronic obstructive
pulmonary disease and heart block
· Useful alternative to ACE inhibitors
when dry persistent cough is a problem
· Monitor serum potassium level
periodically
Angiotensin receptor blockers
Losartan, oral, 25-100 mg daily
Or
Candesartan, oral, 4-32 mg daily
Or
Valsatan, oral, 80-160 mg daily
DISORDERS OF THE CARDIOVASCULAR SYSTEM
Calcium channel blockers
Nifedipine retard, oral, 10-40 mg 12
hourly
Or
Amlodipine, oral, 5-10 mg daily
· Particularly useful in isolated systolic
hypertension
· Short acting formulations should not be
used (see Hypertensive emergencies)
Alpha blockers
Prazosin, oral, 0.5-20 mg in 3 divided doses
starting at an initial dose of 0.5 mg 8-12
hourly and increasing gradually.
· Usually used with other
antihypertensives
· First dose given at night to avoid
hypotension
Centrally acting agents
Methyldopa, oral,
250 mg-1g 8-12 hourly
· Effective in the treatment of
hypertension in pregnancy
· May be used in asthma and heart
failure
Vasodilators
Hydralazine
Adults
Oral, 25-50 mg 12 hourly
Slow IV injection over 20 minutes,
5-10 mg diluted with 10 ml Normal Saline.
Repeat after 20-30 minutes if necessary
· Used in combination with other
antihypertensives
· Useful in hypertension associated with
pregnancy
· Used in hypertensive emergencies
REFER
Refer the following categories of hypertensive patients to an
appropriate specialist:
· Those not achieving the target blood pressure (BP) level after several
months of treatment
· Those on three or more anti-hypertensive drugs, yet have poor BP
control
· Those with worsening of BP over a few weeks or months
· Those with plasma creatinine levels above the upper limit of normal
· Those with diabetes mellitus
· Those with multiple risk factors (diabetes, dyslipidaemia, obesity,
family history of heart disease)
· Those not on diuretics but have persistently low potassium on repeated
blood tests
· All children, young adults and pregnant women with elevated BP
