19th June 2026

Hypertension

Hypertension

Background

Hypertension is a persistent elevation of blood pressure, defined as systolic blood pressure (SBP) ≥140/90 mmHg and/or diastolic blood pressure >90 mmHg. It is associated with an increased risk of cardiovascular disease (CVD; encompassing coronary heart disease, heart failure, stroke, myocardial infarction, atrial fibrillation and peripheral artery disease), stroke and renal failure. 

Epidemiology

Hypertension is a significant contributor to the global burden of disease; it is the leading single contributor to all-cause mortality and disability worldwide. It affects more than 1 billion people and contributes to cardiovascular death more than any other risk factor globally. Certain ethnic groups are disproportionately affected, such as Black individuals, who are in turn more likely to experience complications. The World Health Organisation estimates that hypertension is responsible for nearly 7.5 million deaths worldwide. In the UK, the National Health Survey 2019 reported that hypertension affects approximately 1 in 4 adults and is a leading cause of morbidity and mortality.

The following are recognised risk factors for hypertension:

• Age 
• Family history 
• Obesity 
• Physical inactivity 
• High salt intake 
• Alcohol consumption 
• Smoking 
• Stress 
• Diabetes 
• High cholesterol 
• Sleep apnoea

Aetiology and pathophysiology

The mechanism underlying hypertension is multifactorial, displaying a complex interplay between genetic, environmental and lifestyle factors. Hypertension can be categorised into primary and secondary causes.

Primary hypertension (or essential hypertension) accounts for 90-95% of cases of hypertension and has no identifiable cause.

Secondary hypertension refers to hypertension with a known cause. These are summarised in Table 1.

Table 1. Secondary causes of hypertension

Clinical manifestations

The large majority of patients with hypertension are asymptomatic. Headaches are a common feature, classically occipital. Other associated features give useful clues to the underlying secondary cause of hypertension, for example, weight gain, muscle weakness and thinning skin in Cushing’s syndrome.

Malignant hypertension may be associated with:

• Hypertensive retinopathy
• Visual disturbance
• Cardiac symptoms, e.g. chest pain
• Confusion (cerebral oedema)
• Oliguria or polyuria

Diagnosis and staging 

The evaluation of patients with hypertension involves a combination of clinical examination, laboratory tests, and imaging to assess for evidence of target-organ damage (for example, left ventricular hypertrophy and hypertensive retinopathy) and presence of comorbidities.

NICE guidelines recommend that initial investigations should include 

• Measurement of blood pressure in both arms 
• Physical examination to identify secondary causes of hypertension
• Assessment of cardiovascular risk. Formal assessment may involve using risk calculators such as the Framingham Risk Calculator 1991 or the Q-RISK2

Table 2. Directions by NICE for diagnosing hypertension

In those diagnosed or whilst awaiting confirmation of diagnosis:

• Albumin-creatinine ratio (ACR) and urinalysis: to assess for renal impairment, as indicated by elevated ACR and proteinuria/haematuria 
• Fundoscopy: to assess for hypertensive retinopathy
• 12-lead ECG: to assess for abnormalities in heart rhythm, structure or function 
• Bloods: HbA1c, U&Es, total cholesterol and HDL cholesterol

Hypertension is confirmed if:

• Clinic blood pressure is ≥ 140/90 mmHg.
• ABPM or HBPM provide average values of ≥ 135/85 mmHg.

Table 3. Diagnostic criteria of hypertension by NICE

NICE, National Institute for Health and Care Excellence; ABPM, Ambulatory Blood Pressure Monitoring; HBPM, Home Blood Pressure Monitoring; SBP, systolic blood pressure; DBP, diastolic blood pressure

Table 4. Investigations for hypertension

ABPM, Ambulatory Blood Pressure Monitoring; HBPM, Home Blood Pressure Monitoring; U&Es, urea and electrolytes; TFTs, thyroid function tests

Cardiovascular disease risk assessment

Assessment of cardiovascular disease (CVD) risk is an important component in the management of hypertension. The NICE guidelines recommend using the QRISK3 risk assessment tool to calculate the 10-year risk of developing CVD in people with hypertension who are not already known to be at high risk.

The QRISK3 tool takes into account various factors, including age, sex, ethnicity, smoking status, systolic blood pressure, total cholesterol to HDL ratio, body mass index, family history of coronary heart disease, and other medical conditions such as diabetes, atrial fibrillation, and chronic kidney disease.

For individuals with a 10-year CVD risk of 10% or greater, NICE recommends offering statin therapy for primary prevention, in addition to lifestyle modifications and appropriate antihypertensive treatment. This emphasises the importance of considering overall cardiovascular risk, rather than treating hypertension in isolation.

Management 

Management of hypertension involves a combination of lifestyle interventions and pharmacological therapy, which aim to reduce blood pressure and prevent complications. 

Lifestyle interventions are the first-line treatment for suspected or diagnosed hypertension. This includes:

• Dietary changes: reducing sodium intake, increasing potassium intake, and following a Mediterranean diet
• Regular physical activity
• Weight loss for overweight/obese individuals
• Reducing caffeine
• Limiting alcohol consumption
• Smoking cessation

The choice of pharmacological therapy depends on factors such as age, ethnicity, comorbidities and contraindications. Figure 1 below outlines the patient groups who should be offered antihypertensive treatment. Figure 2 shows the stepped-care treatment protocol recommended by NICE, with medications added or changed based on a patient’s response to treatment.

Summary of NICE guidelines on the initiation of antihypertensive drug treatment. Adapted from NICE guidelines (2019)

Stepped-care treatment protocol for the initiation of antihypertensives by NICE and the BIHS. Adapted from NICE guidelines (2019)

Table 5. NICE recommendations for blood pressure targets in patients with hypertension

Gestational hypertension

Background

Gestational hypertension (GH) is hypertension (blood pressure ≥ 140/90 mmHg on two occasions measured at least 4 hours apart) that develops after 20 weeks’ gestation in previously normotensive women in the absence of proteinuria. GH is a common complication in pregnancy and affects 6-10% of pregnancies globally.

Risk factors 

• Age > 40 years 
• Pre-existing hypertension, including essential hypertension, preeclampsia or gestational hypertension
• Pre-existing renal or vascular disease
• Obesity
• Diabetes
• Nulliparous
• Multiple pregnancy
• Pregnancy interval > 10 years
• Family history of preeclampsia
• Black or Hispanic ethnicity

Clinical features

• Most women are asymptomatic 
• Headache that is persistent and severe
• Visual disturbances 
• Women should be asked about symptoms that suggest pre-eclampsia, e.g. weight gain, peripheral oedema, headaches, and upper abdominal pain

Diagnosis and investigations

Table 6. Investigations for gestational hypertension

Severity classification of gestational hypertension:

• Hypertension: systolic BP ≥ 140/90 mmHg or diastolic BP ≥ 90 mmHg, or both
• Severe hypertension: BP persistently ≥ 160/100 mmHg for a minimum of 4 hours

Complications

• Pre-eclampsia: a severe form of GH, characterised by hypertension, proteinuria and end-organ damage
• Placental abruption: the placenta separates from the uterine wall, causing heavy bleeding and foetal distress
• Intrauterine growth restriction: leads to low birth weight and other complications
• Pre-term delivery: may be necessary if GH is severe or if there are other complications

Management

The management of GH depends on the severity of the condition, and ranges from close monitoring of BP and urine protein levels in mild GH to admission to hospital and antihypertensive treatment in the context of high or persistently elevated BP (summarised in Table 2).

Important considerations

• Lifestyle modifications: the same advice on rest, exercise and work to women with chronic hypertension 
• Antihypertensive treatment: Oral labetalol is 1st line (avoid in asthma). Alternatives include: 
  • Nifedipine if worsening hypertension previously controlled with oral labetalol 
  • Methyldopa, if labetalol or nifedipine are not suitable; avoid postpartum due to risk of depression, and change to an alternative within 2 days of delivery if started.
• Planned early delivery. Indications include the following:
  • Preterm labour or premature rupture of membranes
  • Vaginal bleeding
  • Abnormal foetal testing
  • Intrauterine growth restriction
  • Development of pre-eclampsia or eclampsia
  • Evidence of end-organ damage (e.g. neurological, hepatic or renal dysfunction)
• Corticosteroids (e.g. betamethasone), if planned early delivery < 37 weeks’ gestation is necessary to promote foetal lung maturation, as indicated
• Magnesium sulphate if planned early delivery < 34 weeks’ gestation, for neuroprotection, as indicated 
• Low-dose aspirin (PO 75mg) in subsequent pregnancies to reduce the risk of pregnancy-induced hypertension and pre-eclampsia

Table 7. Management of gestational hypertension

Postnatal investigation, monitoring and treatment

• Continue monitoring the mother’s BP. Measure BP daily for the first 2 days after birth, at least once between day 3 and day 5, and as clinically indicated afterwards.
• Continue antihypertensive treatment if required. Start treatment if BP ≥ 150/100 mmHg and they were not treated during pregnancy. Reduce treatment dosages if BP falls < 130/80 mmHg
• Follow-up with GP or specialist 6-8 weeks after birth, or 2 weeks after transfer to community care for women who remain on antihypertensive treatment

Pre-eclampsia and eclampsia

Background

Pre-eclampsia is a systemic syndrome in pregnancy that usually occurs after 20 weeks’ gestation, characterised by hypertension and proteinuria. The mechanism underlying pre-eclampsia has not been fully elucidated; however, it is thought to be related to abnormal placentation and inadequate trophoblastic invasion of the uterine spiral arteries, leading to vasoconstriction, increased systemic vascular resistance, and decreased organ perfusion. Eclampsia is a complication of pre-eclampsia, characterised by seizures.

Epidemiology

Nearly 2-8% pregnancies worldwide are implicated by pre-eclampsia. Eclampsia is a rare complication, with an incidence of 1 in 2,000 pregnancies.

Risk factors 

• Nulliparity 
• Previous maternal history or family history
• BMI > 30
• Maternal age > 40 years
• Multiple pregnancy
• > 10-year interval since previous pregnancy
• Sub-fertility 
• Gestational hypertension
• Pre-existing diabetes
• Pre-existing renal or vascular disease
• PCOS
• Autoimmune disease

Clinical features

• The key clinical features of pre-eclampsia are hypertension and proteinuria after 20 weeks’ gestation
• Women may be asymptomatic and diagnosed at a routine clinic visit
• Headaches (usually frontal): indicates severe pre-eclampsia 
• Visual disturbances
• Peripheral oedema
• Upper abdominal pain (usually right upper quadrant)
• Nausea and vomiting 
• Breathlessness (due to pulmonary oedema): one of the main causes of maternal mortality 
• Seizures: requires prompt admission to ICU, stabilisation and delivery
• Oliguria

HELLP syndrome is a variant of severe pre-eclampsia characterised by haemolysis, elevated liver enzymes, and low platelets.

Diagnosis and investigations

Diagnosis is based on the presence of the following after 20 weeks’ gestation:

• Hypertension: SBP ≥ 140 mmHg and/or a DBP ≥ 90 mmHg on 2 occasions at least 4 hours apart 
• Proteinuria: ≥ 30 mg/mmol on PCR or ≥ 0.3g/24 hours or ≥ 1+ on a urine dipstick

After diagnosing pre-eclampsia, further testing should be performed, including foetal assessment for complications and maternal testing for systemic involvement. A summary of the investigations can be found in Table 1.

Table 8. Investigations for pre-eclampsia

PCR, protein: creatinine ratio; PIGF, placental growth factor

Severity classification of pre-eclampsia:

• Hypertension: BP of 140/90 – 159/109 mmHg 
• Severe hypertension: BP of ≥ 160/110 mmHg

Complications

Maternal complications

• Seizures (eclampsia)
• Placental abruption
• Pulmonary oedema
• Pregnancy-associated stroke
• Cardiovascular disease 
• Renal failure
• Death

Foetal complications 

• IUGR
• Pre-term delivery
• Intrauterine death

Management

Managing pre-eclampsia requires attention to the following critical considerations: 

• Monitoring
• Delivery: date and method
• Controlling blood pressure
• Controlling seizures
• Postnatal fluid management

Important considerations

• Antihypertensive treatment: choice should be based on pre-existing treatment, possible side effects, maternal vs foetal risk, and the woman’s preference. Combination therapy may be required.  
• Corticosteroids (e.g. betamethasone) to promote foetal lung maturation, as indicated 
• Magnesium sulphate if planned early delivery. It is the treatment of choice for eclampsia. Monitor for signs of magnesium toxicity (e.g. respiratory depression and loss of reflexes); calcium gluconate may be used as a reversal agent. 
• Delivery: the definitive management of pre-eclampsia, however it may take a few days to resolve completely. Indications for planned early delivery < 37 weeks may include the following: 
  • Inability to control maternal BP despite ≥ 3 classes of antihypertensives
  • Maternal pulse oximetry < 90%
  • Progressive deterioration in blood results
  • Ongoing neurological features, e.g. severe intractable headache, repeated visual scotomata
  • Placental abruption
  • Reversed end-diastolic flow in umbilical artery doppler velocimetry, a non-reassuring CTG, or stillbirth

Table 9. Management of pre-eclampsia

fullPIERS, Pre-eclampsia Integrated Estimate of RiSk; PREP-S, Prediction of complications in early-onset pre-eclampsia (using a survival model).

Postnatal investigation, monitoring and treatment

• Measure BP at least once between day 3 and 5 after birth, then on alternate days until normal, if BP was abnormal
• Continue antihypertensive treatment if required. Start treatment if BP ≥ 150/100 mmHg and they were not treated during pregnancy. Reduce treatment dosages if BP falls < 130/80 mmHg
• Follow-up with GP or specialist 6-8 weeks after birth, or 2 weeks after transfer to community care for women who remain on antihypertensive treatment 
• The main risk to the mother in this period is fluid overload; therefore, fluid management is crucial. NICE guidelines fluid restriction to 80 ml/hour

Hypertensive emergency

Background

Hypertensive emergency is defined as a significantly elevated blood pressure which usually results in end-organ damage. Generally, this is a systolic blood pressure greater than 180mmHg and a diastolic blood pressure of 120mmHg. End-organ damage may include acute kidney injury, ischaemic or haemorrhagic stroke, myocardial ischaemia or heart failure.

Epidemiology

1-2% of patients with hypertension will suffer from a hypertensive emergency in their lives.

Risk factors 

Hypertensive emergency occurs largely due to undiagnosed as well as poorly controlled essential hypertension. It may also be due to secondary hypertension caused by a systemic condition such as phaeochromocytoma or hyperaldosteronism.

Poor lifestyle choices such as increased salt intake and obesity, as well as certain medications such as steroids, sympathomimetics and NSAIDs, may also predispose a hypertensive emergency.

Clinical features

A patient with hypertensive emergency may present with no symptoms and may incidentally find a very high blood pressure. Patients, however, may present with a variety of symptoms seen in the table below.

Diagnosis and investigations

Diagnosis is generally based on a systolic blood pressure >180mmHg and a diastolic pressure >120mmHg. 

Investigations may include:

• CT head: This may reveal a hemorrhagic stroke, but will not rule out an ischaemic stroke
• Fundoscopy: to look for signs of papilloedema 
• Urine dipstick: to look for blood and protein in the urine
• Renal profile: deranged renal function may explain 
• ECG: to look for left ventricular hypertrophy and rule out ischaemia
• Cardiac enzymes: to rule out myocardial infarction
• Urine drug screen: illicit drugs
• Thyroid function tests
• Plasma renin and aldosterone levels may point towards hyperaldosteronism as a cause 
• Urine metanephrines for phaeochromocytoma
• 24-hour urinary cortisol for Cushing’s syndrome 
• CXR
• CT aortogram if aortic dissection is suspected.
• Renal ultrasound / MRA

Complications

• Heart failure
• Cerebral ischaemia, haemorrhage, encephalopathy
• Acute kidney injury

Management

Management of hypertensive emergencies should not be delayed whilst investigating end-organ damage and underlying cause. Patients are usually kept on a cardiac monitor and commenced on parenteral anti-hypertensive medication with the aim of gradual reduction in blood pressure to avoid renal, cerebral or cardiac ischaemia. This is with a few exceptions, as detailed below. 

Generally, it is recommended to reduce blood pressure by no more than 25% in the first hour. A further reduction is done in the next 4-6 hours with an aim of reaching a normal blood pressure within 24-48 hours, and weaning parenteral infusion.

There are a few exceptions:

• Patients suffering from an ischaemic stroke should not have an aggressive reduction in blood pressure and may benefit from maintaining a very high blood pressure to maintain cerebral perfusion.
• On the other hand, patients with ischaemic stroke who are candidates for thrombolysis should have a gentle reduction in their blood pressure <185/110 before thrombolysis.
• Patients suffering from an aortic dissection should have aggressive reduction in blood pressure within the first hour to a systolic less than 120mmHg.
• Patients with pre-eclampsia, eclampsia or phaeochromocytoma crisis should have a reduction in their blood pressure within the first hour to a systolic <140mmHg.

Specific emergencies

Malignant hypertension

     Malignant hypertension is a subcategory of hypertensive emergency, which includes either grade III or IV retinopathy. Hypertensive encephalopathy refers to neurological symptoms caused by severely elevated blood pressure and typically improves with blood pressure correction. Intracranial haemorrhage may occur with malignant hypertension.

Management:

• 1st line – Labetalol infusion
• 2nd line – Nicardipine or nitroprusside if no evidence of raised intracranial pressure
• 3rd line – Fenoldopam

Aim to reduce mean arterial pressure by 20-25% within the first 2-4 hours, then to 160/100-110 mmHg within the next 2-6 hours [2].

Myocardial Ischaemia or Infarction

Management:

1. 1st line – Esmolol + GTN infusion
2. 2nd line – Labetalol + GTN infusion

Heart failure / pulmonary oedema

IV nitroglycerin or nitroprusside may be considered as an adjuvant to diuretic therapy. Due to the potential of significant hypotension, nitroprusside should be used with invasive haemodynamic monitoring, typically in the intensive care setting.

Aortic Dissection

Aortic dissection requires particularly aggressive blood pressure management to reduce the risk of propagation of the dissection.

Aortic dissection is classified based on its location and duration:

1. Stanford Classification: 
   • Type A: Involves the ascending aorta, with or without the involvement of the aortic arch and descending aorta
   • Type B: Involves only the descending aorta
2. DeBakey Classification: 
   • Type I: Originates in ascending aorta, propagates at least to the aortic arch
   • Type II: Originates in and is confined to the ascending aorta
   • Type III: Originates in descending aorta, extends distally or proximally

Management:

1. 1st line – Combination of IV beta-blocker (e.g., labetalol or esmolol) and vasodilator (e.g., nicardipine or nitroprusside)
2. If using labetalol alone, higher doses may be required

Targets:

• Reduce systolic BP to <120 mmHg within the first hour of presentation
• Maintain systolic BP < 120 mmHg or to the lowest BP that maintains adequate end-organ perfusion
• Target heart rate of 60 to 80 bpm

Definitive treatment depends on the type of dissection: 

• Type A typically requires urgent surgical intervention
• Uncomplicated Type B can often be managed medically, with endovascular repair considered in certain cases

Remember, in all cases, the key principle is to lower blood pressure gradually to avoid organ hypoperfusion, while being mindful of the specific risks associated with each condition.

References

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• National Institute for Health and Care Excellence. (2019). Hypertension in pregnancy: diagnosis and management. Retrieved from https://www.nice.org.uk/guidance/ng133.
• BMJ Best Practice. (2021). Hypertensive disorders of pregnancy. Retrieved from https://bestpractice.bmj.com/topics/en-gb/528.
• https://bestpractice.bmj.com/topics/en-gb/27
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