Persistently high resting blood pressure (>140/90 mmHg for at least two measurements five minutes apart with patient seated) on at least 2 or 3 occasions 1 week apart.
Classification of blood pressure (BP)
CATEGORY | SBP MMHG | – | DBP MMHG |
---|---|---|---|
Normal | <120 | and <80 | |
Pre-hypertension | 120-139 | or | 80-89 |
Hypertension, stage 1 | 140-159 | or | 90-99 |
Hypertension, stage 2 | >160 | or | >100 |
SBP=systolic blood pressure; DBP=diastolic blood pressure
Causes
- In the majority of cases, the cause is not known (essential hypertension)
Secondary hypertension is associated with:
- Kidney diseases
- Endocrine diseases
- Eclampsia/pre-eclampsia
- Medicines (steroids and decongestants containing caffeine and pseudoephedrine)
Risk factors
- Family history, race
- Obesity, physical inactivity
- Excessive intake of salt and alcohol
- Diabetes and dyslipidaemia
Clinical features
The majority of cases are symptomless and are only discovered on routine examination or screening.
General symptoms include:
- Headache
- Palpitations, dizziness
Hypertension may present as a complication affecting:
- Brain (stroke)
- Heart (heart failure)
- Kidney (renal failure)
- Eyes (impairment of vision)
Differential diagnosis
- Anxiety
Investigations
To identify complications and possible cases of secondary hypertension:
- Urine analysis
- Blood sugar
- Plasma urea and electrolytes
- Chest X-ray
- ECG
Management of hypertension
Target: blood pressure below 140/90 mmHg
TREATMENT
Stage 1
Lifestyle adjustments
- Do not add extra salt to cooked food, increase physical activity/exercise, reduce body weight Stop smoking
- Decrease alcohol intake
If all the above fail (within 3 months), initiate medicine therapy
- Give bendroflumethiazide 2.5-5 mg each morning
- If not controlled after 1 month, treat as in stage 2
Stage 2
- Emphasize lifestyle changes
- Bendroflumethiazide 2.5-5 mg each morning
Plus - Calcium channel blocker (CCB) e.g.
- Nifedipine 20-40 mg every 12 hours
Alternative in special situation (diabetes, heart failure):
- ACE inhibitor e.g.
- Enalapril 5-20 mg once daily (max 40 mg) or
- Captopril 6.25-25 (max 50 mg) every 8 hours
If intolerence to ACE inhibitors
- Angiotensin II receptor antagonist (ARB) e.g.
- Losartan 50 mg once or twice daily
If not controlled after one month with 2 medicines,
- Use 3 drugs (bendroflumethiazide plus ACE inhibitor plus calcium channel blocker)
If not controlled, increase all medicines to maximum dose and consider adding beta blockers
- Atenolol 50-100 mg daily
If BP >180/110 mmHg, but patient is asymptomatic and there is no evidence of complications
- Observe the patient for some hours and start treatment with 2 medicines
- Bendroflumethazide plus Calcium channel
blocker or ACE inhibitor
If not better after one week, add a third medicine
If not better, consider adding
- Beta blockers: atenolol 25-100 mg daily or
- Hydralazine 25-50 mg every 12 hours
Note
- Bendroflumethiazide: Potassium supplements are seldom required; only use in susceptible patients
Cautions
- In pregnancy, do NOT use ACE inibitors and diuretics. Methyldopa and calcium channel blockers are safe to use
- Atenolol: do not use in heart failure or asthma. Use carvedilol if necessary.
Choice of antihypertensive medicine
Choice of medicine may depend on concomitant risk factors/ other conditions: the table below indicates the suitable medicines for such patients.
RISK FACTOR | DIURETIC | BETA BLOCKER | ACE INHIBITOR /ARBS | CCB | ALDOSTERON ANTAGONIST |
---|---|---|---|---|---|
Heart failure | use | use | use | Do not use | use |
Post myocardial infarction | Do not use | use | use | Do not use | Do not use |
Angina | Do not use | use | Do not use | use | |
Diabetes | use | Do not use | use | use | Do not use |
Mild/moderate kidney disease |
use | Do not use | use | Do not use | Do not use |
Advanced chronic kidney disease |
Use | Use | Do not use | Use | |
Stroke | Use | Do not use | Do not use | Use | Do not use |
*Carvedilol only
Prevention
- Regular physical exercise
- Reduce salt intake
- Healthy diet, stop smoking
- Periodic screening of blood pressure