Hypertension


Hypertension (or high blood pressure - HBP) is defined as elevated blood pressure (BP) at rest that persists over time i.e. measured 3 times during 3 separate consultations over a period of three months.
Essential hypertension is defined as HBP of undetermined cause (the large majority of cases).

The global overall prevalence of HBP in adults aged 25 and over is around 40%.1

Serious complications of HBP can be acute (hypertensive encephalopathy, left-sided heart failure, acute renal failure) or delayed i.e. occur after a long period during which HBP has not been controlled (stroke, ischaemic heart disease, peripheral arterial disease, chronic renal impairment).

For pregnancy-induced hypertension, see Essential obstetric and newborn care, MSF.

Clinical features

– HBP thresholds:


HBP classification

Blood pressure (BP) in mmHg

Systolic (SBP)

Diastolic (DBP)

Mild

140 or over

90 or over

Moderate

160 or over

100 or over

Severe

180 or over

110 or over


– Severe HBP is defined more by the presence of serious end-organ damage than the blood pressure reading:
• Uncomplicated hypertensive crisis:
SBP ≥ 180 and/or DBP ≥ 110 and some symptoms (moderate headaches, epistaxis, dizziness, tinnitus, eye floaters) but no signs of end-organ damage;
• Hypertensive emergency:
SBP ≥ 180 and/or DBP ≥ 110 and signs of end-organ damage:
   - intense headaches, nausea/vomitting, confusion, seizures, coma in the event of hypertensive encephalopathy;
   - dyspnoea, chest pain in the event of heart failure or cardiac ischaemia;
   - rapid and/or irregular heart rate in the event of heart failure;
   - anuria, oliguria in the event of renal impairment.

– History and clinical examination should look for:
• medications being taken that can cause or aggravate HBP;1
• focal neurological sign(s) suggestive of stroke;
• comorbidities and risk factors: heart failure, diabetes, renal impairment; excessive smoking or consumption of alcohol, excess weight (BMI ≥ 25), etc.

Paraclinical investigations

− Blood test: ionogram (particularly serum potassium levels), serum creatinine. 
− Other necessary laboratory tests according to comorbidities (e.g. diabetes).
− ECG and echocardiogram to look for signs of heart failure, coronary disease, or arrhythmia.

Long-term treatment

– The goal of treatment is to lower BP. Target BP are:
• SBP < 140 and/or DBP < 90
• SBP < 140 and/or DBP < 80 in diabetic patients
• SBP < 150 and/or DBP < 90 in patients aged > 80 years

– In patients with mild HBP (SBP ≥ 140 and/or DBP ≥ 90) without associated cardiovascular disorders or stroke or diabetes, start with lifestyle and dietary advice. 

– Pharmacological treatment is indicated in the following cases:
• SBP ≥ 160 and/or DBP ≥ 100;
• HBP associated with cardiovascular disorder, stroke or diabetes;
• HBP not controlled by lifestyle and dietary changes alone.

Lifestyle and dietary advice
Recommended for all hypertensive patients:
− Reduce calorie and salt intake.
− Regular physical activity.
− Weight loss if BMI ≥ 25.
− Stop smoking and alcohol consumption.

Pharmacological treatment 
Start with a monotherapy. One of four classes of antihypertensive drugs can be chosen as first line treatment, according to the patient’s characteristics (e.g. age, contra-indications, etc.). For information: 

Patient with no comorbidities

Patient with comorbidities

Thiazide diuretic

After a stroke: thiazide diuretic

Patient > 65 years: thiazide diuretic or calcium channel blocker 

Diabetic patient:
angiotensin converting enzyme (ACE) inhibitor
or beta blocker if concomitant cardiovascular disorder

Patient with black skin: thiazide diuretic or calcium channel blocker (avoid ACE inhibitors)

Renal impairment: ACE inhibitor

Thiazide diuretic
hydrochlorothiazide PO: 12.5 to 25 mg once daily in the morning (max. 25 mg daily)

Angiotensin converting enzyme inhibitor
enalapril PO: start with 5 mg once daily. Gradually increase, every 1 to 2 weeks, according to BP, up to 10 to 20 mg once daily (max. 40 mg daily).
In elderly patients or patients taking a diuretic or patients with renal impairment: start with 2.5 mg once daily.

Calcium channel blocker
amlodipine PO: 5 mg once daily. Increase to 10 mg once daily if necessary (max. 10 mg daily). 
In elderly patients or patients with hepatic impairment: start with 2.5 mg once daily.

Beta-blocker (contra-indicated in patients with asthma)
bisoprolol PO: 5 to 10 mg once daily in the morning
Do not stop treatment abruptly (risk of malaise, angina).

In patients with no comorbidity start with a thiazide diuretic and check BP after 4 weeks of treatment. 
If the treatment has been correctly taken but there is no improvement after 4 weeks, add a second antihypertensive drug.
After 4 weeks of bitherapy, reevaluate. If the patient’s BP remains too high, consider triple-therapy.

In diabetic patients, if there is no improvement after 4 weeks of AEC inhibitor treatment taken correctly, add a calcium channel blocker.

In patients with a cardiac disorder (heart failure or coronary heart disease), bitherapy is usually necessary from the start (AEC inhibitor + beta-blocker).

Surveillance and monitoring

Laboratory surveillance
According to treatment (diuretic, AEC inhibitor, etc.): ionogram and serum creatinine every 6 to 12 months.

Clinical monitoring
− Consultations every 3 months (BP, weight), then every 6 months, then individualised frequency of consultations depending on the patient's characteristics.
− Management of comorbidities (e.g. diabetes).

Patient education
− Lifestyle and dietary advice.
− Treatment observance: do not stop treatment abruptly, particularly if taking beta blockers (risk of malaise, angina).
− Consultation in the event of epistaxis, tinnitus, eye floaters; adverse effects of treatment (e.g. cough with AEC inhibitors, erectile dysfunction with beta blockers, oedema with calcium channel blockers).

Treatment of hypertensive crisis

Uncomplicated hypertensive crisis 
Most frequent. Reassure the patient and prescribe rest. Check BP a few days later to start or adapt treatment.

Hypertensive emergency
Treat in an intensive care unit.
– Hypertensive encephalopathy:
The aim is to reduce BP by 10 to 15% within the first hour and to not reduce it more than 25% during the first 24 hours.
labetalol IV (contra-indicated in patients with asthma2 ):
20 mg over at least 1 minute. Administer another dose after 10 minutes if BP has not decreased. If necessary, 40 mg doses are administered every 10 minutes until hypertension is controlled (max. 300 mg total dose).
– Stroke: do not try to decrease BP during the first 3 days unless SBP is ≥ 220 and/or DBP ≥ 120 (in this event administer labetalol). 
– Acute pulmonary oedema: see Acute heart failure.



Footnotes
Ref Notes
1 Consider secondary hypertension caused by medications being taken, mainly NSAID, corticosteroids, opioids, oral estroprogestogens, etc. Treatment, in this event, consists in stopping or replacing the causative drug.
2 In patient with asthma, hydralazine IV: 5 to 10 mg diluted in 10 ml of 0,9% sodium chloride administered by slow IV, to be repeated after 20 to 30 minutes if necessary.


References

  1. World Health Organization. Media center. High blood pressure: a public health problem, 2018
    http://www.emro.who.int/media/world-health-day/public-health-problem-factsheet-2013.html [Accessed 12 September 2018]