Hypertension refers to persistently elevated blood pressure.

According to NICE hypertension guidance (updated 2022), hypertension is diagnosed when clinic blood pressure readings are above 140/90 mmHg, with confirmation by ambulatory or home blood pressure monitoring showing readings above 135/85 mmHg.

Causes of Hypertension

Approximately 90% of cases are due to essential (primary) hypertension. In essential hypertension, raised blood pressure develops without an identifiable secondary cause.

Secondary causes of hypertension can be remembered using the “ROPED” mnemonic:

• R – Renal disease
• O – Obesity
• P – Pregnancy-related hypertension or pre-eclampsia
• E – Endocrine causes
• D – Drugs (e.g. alcohol, corticosteroids, NSAIDs, oestrogen, liquorice)

Renal disease is the most frequent cause of secondary hypertension. In cases where blood pressure is severely elevated or resistant to treatment, renal artery stenosis should be considered. This can be investigated using duplex ultrasound, MR angiography, or CT angiography.

Many endocrine disorders can lead to hypertension. Primary hyperaldosteronism (Conn’s syndrome) is particularly important and may account for 5–10% of hypertensive patients.

Specialist investigations should be considered in individuals under 40 years of age or when a secondary cause of hypertension is suspected.

Complications

Sustained high blood pressure increases the risk of:

• Ischaemic heart disease (including angina and acute coronary syndrome)
• Cerebrovascular disease (stroke or intracranial haemorrhage)
• Vascular disease (peripheral arterial disease, aortic dissection, aortic aneurysm)
• Hypertensive retinopathy
• Hypertensive nephropathy
• Vascular dementia
• Left ventricular hypertrophy
• Heart failure

Left Ventricular Hypertrophy

Chronic hypertension can lead to left ventricular hypertrophy (LVH). As the left ventricle must pump against increased systemic resistance, myocardial thickening occurs.

On examination, this may present as a sustained and forceful apex beat. LVH may be suggested on ECG using voltage criteria, but echocardiography is the most accurate diagnostic tool.

Diagnosis

NICE advises blood pressure screening every 5 years for adults. More frequent measurement is recommended in individuals with borderline readings, and annual checks are advised for patients with type 2 diabetes.

Patients with clinic blood pressure readings between 140/90 mmHg and 180/120 mmHg should undergo 24-hour ambulatory blood pressure monitoring or home blood pressure monitoring to confirm the diagnosis.

Blood pressure readings taken in clinical settings are often higher than those measured at home—this phenomenon is known as “white coat syndrome”. A white coat effect is defined as a difference of more than 20/10 mmHg between clinic and ambulatory or home readings.

NICE recommends measuring blood pressure in both arms. If there is a difference of more than 15 mmHg, the higher reading should be used for diagnosis and management.

Staging of Hypertension

End-Organ Damage Assessment

For all patients with a new diagnosis of hypertension, NICE recommends the following investigations:

• Urine albumin:creatinine ratio to assess for proteinuria, and dipstick testing for microscopic haematuria (renal damage)
• Blood tests including HbA1c, renal function, and lipid profile
• Fundoscopy to assess for hypertensive retinopathy
• ECG to identify cardiac abnormalities, including left ventricular hypertrophy

NICE also recommends calculating the QRISK score, which estimates the 10-year risk of stroke or myocardial infarction. If QRISK is greater than 10%, patients should be offered statin therapy, starting with atorvastatin 20 mg at night.

Management

Lifestyle Measures

Lifestyle modification is a core component of hypertension management and includes:

• Adopting a healthy diet
• Smoking cessation
• Reducing alcohol, caffeine, and salt intake
• Engaging in regular physical activity

Antihypertensive Medications

Common drug classes used in treatment include:

• A – ACE inhibitor (e.g. ramipril)
• B – Beta blocker (e.g. bisoprolol)
• C – Calcium channel blocker (e.g. amlodipine)
• D – Thiazide-like diuretic (e.g. indapamide)
• ARB – Angiotensin II receptor blocker (e.g. candesartan)

NICE recommends ARBs instead of ACE inhibitors in patients of Black African or African-Caribbean family origin. In treatment algorithms, ARB can replace A for these individuals.

ARBs are also used when ACE inhibitors are not tolerated, most commonly due to persistent dry cough. ACE inhibitors and ARBs must not be used together.

Thiazide-like diuretics may replace calcium channel blockers when the latter are not tolerated, frequently due to ankle oedema.

Stepwise Treatment (NICE)

Recommendations vary by age, ethnicity, and diabetes status:

• Step 1:
  • Under 55 years, or any age with type 2 diabetes → A
  • Over 55 years or Black African/African-Caribbean → C
• Step 2:
  • A + C, or
  • A + D, or
  • C + D
• Step 3:
  • A + C + D
• Step 4:
  • A + C + D + fourth agent

Step 4: Choice of Fourth Agent

This depends on serum potassium:

• ≤ 4.5 mmol/L: consider a potassium-sparing diuretic (e.g. spironolactone)
• > 4.5 mmol/L: consider an alpha blocker (e.g. doxazosin) or a beta blocker (e.g. atenolol)

Medication adherence should always be reviewed. Patients with blood pressure that remains uncontrolled at step 4 should be referred for specialist management.

Potassium Balance and Monitoring

Spironolactone is a potassium-sparing diuretic that blocks aldosterone action in the kidneys, promoting sodium loss while conserving potassium. It is particularly useful when thiazide diuretics cause hypokalaemia.

However, spironolactone increases the risk of hyperkalaemia, as do ACE inhibitors. Thiazide-like diuretics may also cause electrolyte disturbances. For this reason, regular monitoring of U&Es is essential when using these medications.

Treatment Targets

Hypertensive Emergency

Accelerated (malignant) hypertension refers to severe hypertension (>180/120 mmHg) accompanied by retinal haemorrhages or papilloedema.

NICE recommends same-day referral for patients with suspected accelerated hypertension. Therefore, anyone with blood pressure above 180/120 mmHg should undergo fundoscopy to assess for these changes.

Other features that also warrant urgent assessment include confusion, heart failure, suspected acute coronary syndrome, and acute kidney injury.

Patients admitted with a hypertensive emergency are investigated for secondary causes and end-organ damage, and their blood pressure is closely monitored while treatment is initiated.

Intravenous Treatment Options

IV antihypertensive therapy should be guided by an experienced specialist and may include:

• Sodium nitroprusside
• Labetalol
• Glyceryl trinitrate
• Nicardipine

The rate of blood pressure reduction must be individualised. In elderly or frail patients, overly rapid reduction can cause ischaemia, as higher pressures may be needed to perfuse narrowed vessels.

Last updated November 2025