HYPERTENSION

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