Hypertension

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oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

Hypertension is a major risk factor for cardiovascular disease (CVD) - cerebrovascular events (CVEs) and ischaemic heart disease (IHD) - and is therefore one of the most important preventable causes of premature morbidity and mortality in developed and developing countries.

Hypertension is often symptomless, so screening is vital - before damage is done. Many surveys continue to show that hypertension remains underdiagnosed, undertreated and poorly controlled in the UK.[1] Overall, the prevalence of hypertension (at least ≥140/90 mm Hg or on treatment for hypertension) in those aged over 35 was 31% in men and 28% in women.[2] 

The prevalence significantly increased with age in both sexes:[2] 

  • About 33% of men and 25% of women aged 45-54 years have hypertension.
  • About 66% of men and 78% of women aged ≥75 years or older have hypertension.

All adults should have their blood pressure (BP) measured, at least every five years up to the age of 80, and at least annually thereafter.[3] 

Measuring blood pressure[3]

  • Use a correctly calibrated and maintained machine (manual or automatic).
  • Seated BP is adequate except in elderly patients or those with diabetes who may have orthostatic hypotension (standing BP is needed as well - after at least one minute's standing). If standing systolic blood pressure (SBP) is 20 mm Hg or lower than when seated, review medication, and measure all subsequent blood pressures with the person standing (consider specialist referral if postural hypotension symptoms persist).
  • Remove tight clothing and support the arm with the hand relaxed and the cuff (of appropriate size) at heart level.
  • Initially, measure BP in both arms; if there is a persistent difference of >20 mm Hg between arms then ensure subsequent blood pressures are taken in the arm with the higher reading.
Use an automated machine or the following manual method (if the pulse is irregular (eg, in atrial fibrillation), always use the manual method):
  • Inflate the cuff whilst palpating the brachial artery, until the pulse disappears. This provides an estimate of systolic pressure.
  • Inflate the cuff until 30 mm Hg above systolic pressure, then place a stethoscope over the brachial artery. Deflate the cuff at 2 mm Hg per second.
  • Systolic pressure: the appearance of sustained repetitive tapping sounds (Korotkov I). Diastolic pressure: usually the disappearance of sounds (Korotkov V). However, in some individuals (eg, pregnant women) sounds are present until the zero point. In this case the muffling of sounds,(Korotkov IV), should be used.
  • Record to the nearest 2 mm Hg.
  • If initial BP is ≥140/90 mm Hg, take a second or even third reading and record the lowest (discard the initial reading) as the clinic BP.

If BP in the GP surgery is ≥140/90 mm Hg then offer ambulatory blood pressure monitoring (ABPM) to confirm the suspected hypertension, or home blood pressure monitoring (HBPM) if ABPM is not available or not tolerated.[3]

  • If using ABPM - take ≥2 readings every waking hour, and average at least 14 measurements when deciding whether hypertension is present.
  • If using HBPM - on each occasion take two consecutive BP measurements (<1 minute apart), with the person seated. Take readings twice daily (morning and evening) over ≥4 days (ideally 7 days) - disregard the first day and then average the rest.

Those with high normal values (130-139/85-89 mm Hg) subsequently should be checked annually.

While waiting for further BP readings to confirm diagnosis of hypertension, look for target organ damage and carry out cardiovascular risk assessment with a suitable assessment tool - look for hypertensive retinopathy, left ventricular hypertrophy on ECG, and perform blood tests (serum electrolytes, creatinine, eGFR, fasting glucose and lipids) and urinalysis for albuminuria, proteinuria or haematuria ± albumin:creatinine ratio.

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Blood pressure (BP) has a skewed normal distribution within the population and the currently accepted model assumes risk is continuously related to BP. The National Institute for Health and Care Excellence (NICE) recommends the following definitions:

  • Stage 1 hypertension - BP in surgery/clinic is ≥140/90 mm Hg and ABPM or HBPM is ≥135/85 mm Hg.
  • Stage 2 hypertension - BP in surgery/clinic  is ≥160/100 mm Hg and ABPM or HBPM is ≥150/95 mm Hg.
  • Severe hypertension - BP in surgery/clinic is ≥180/110 mm Hg or higher.
  • Hypertensive crisis: there are two types
    • Malignant (accelerated) hypertension: this is a syndrome characterised by severe hypertension (eg, systolic >200 mm Hg, diastolic >130 mm Hg) accompanied by end-organ damage - eg, encephalopathy, dissection, pulmonary oedema, nephropathy, eclampsia, papilloedema and/or angiopathic haemolytic anaemia. Accelerated hypertension needs urgent (same day) assessment and immediate treatment to reduce the BP within minutes to hours.[3]This is also termed hypertensive emergency.
    • Hypertensive urgency:  a systolic blood pressure (SBP) ≥180 mm Hg or a diastolic blood pressure (DBP) ≥120 mm Hg without impending end-organ damage. Treatment should safely reduce BP over a few days.
  • Suspected phaeochromocytoma: consider this diagnosis if there is labile or postural hypotension, headache, palpitations, pallor and profuse sweating - refer for urgent (same day) assessment.[3][4] This is also termed urgent hypertension.
  • Systolic or diastolic pressure: for many years diastolic pressure was considered to be more important than systolic pressure.  They are both important determinants of cardiovascular risk.
  • Hypertension in the elderly: although age-related, rise in systolic pressure can be considered part of the 'normal' ageing process; isolated systolic hypertension (ISH) in the elderly should not be ignored. The benefits of treatment are far greater than treating moderate hypertension in middle-aged patients.[5]
  • Essential hypertension (primary, cause unknown) accounts for the majority of cases, particularly in the older patient.
  • Secondary hypertension is commonly caused by renal disease or pregnancy:
    • Renal disease - approximately 75% are from intrinsic renal disease: glomerulonephritis, polyarteritis nodosa, systemic sclerosis, chronic pyelonephritis, or polycystic kidneys.
      Approximately 25% are due to renovascular disease - most frequently atheromatous (eg, elderly cigarette smokers with peripheral vascular disease) or fibromuscular dysplasia (more common in younger females).
    • Endocrine disease:[4] 
      • Cushing's syndrome
      • Conn's syndrome
      • Phaeochromocytoma
      • Acromegaly
      • Hyperparathyroidism
    • Coarctation.
    • Pre-eclampsia and hypertension in pregnancy.[6] 
    • Drugs and toxins - eg, alcohol, cocaine, ciclosporin, tacrolimus, erythropoietin, adrenergic medications, decongestants containing ephedrine and herbal remedies containing licorice.

It is usually asymptomatic, except accelerated hypertension.

All patients need a full history and physical examination. Look hard for a cause (renal, endocrine, etc. - as above) in the young, severe hypertensive and those with resistant hypertension.[4][7][8] 

  • Take a full drug history (non-steroidal anti-inflammatory drugs (NSAIDs), oral contraceptives, steroids, licorice, sympathomimetics, ie cold cures).
  • Are they aware of the hypertension? Episodic feelings 'as if about to die' or headaches, or paroxysmal sweats or palpitations, suggest phaeochromocytoma.
  • Consider renal causes: is there a present, past or family history of renal disease? Are the kidneys palpable? Is there an abdominal or loin bruit (renovascular disease) or delayed or weak femoral pulses (coarctation).
  • Does the patient look Cushingoid or might he or she have Conn's syndrome (tetany, weak muscles, polyuria, hypokalaemia)?
  • Consider contributory factors: obesity, excess alcohol, salt intake[9] and lack of exercise, environmental stress, and cardiovascular risk factors (smoking, diabetes, cholesterol and family history) ready for your management plan.

Assess the degree of end-organ damage or complications of hypertension - eg, previous CVE, transient ischaemic attack (TIA), dementia or known left ventricular hypertrophy (LVH)/left ventricular (LV) strain, IHD, peripheral vascular disease, or renal impairment. Perform ophthalmoscopy; dilate with 1% tropicamide if there is poor view.

Investigations

  • Looking for target-organ damage:[4] 
    • Urine dipstick test for protein and blood.
    • Serum creatinine and electrolytes and eGFR.
    • Renal ultrasound scan.
    • 12-lead ECG (looking for LVH or signs of IHD).
    • Echocardiography.
  • Cardiovascular disease prevention:
    • Fasting blood glucose.
    • Fasting serum total and high-density lipoprotein (HDL) cholesterol.
  • Specific investigations for a suspected secondary cause:[4] 
    • 24-hour urinary metanephrines.
    • Urinary free cortisol and/or dexamethasone suppression test.
    • Renin/aldosterone levels.
    • Plasma calcium.
    • Magnetic resonance imaging of the renal arteries.

Referral to a specialist may be appropriate for some of these tests.

  • Urgent treatment is needed: accelerated hypertension, severe hypertension (>220/>120 mm Hg) or impending complications (eg, TIA, LV failure).
  • Possible underlying cause: low K+, Na+ elevated (possible Conn's syndrome); elevated creatinine, proteinuria or haematuria; sudden onset or rapidly worsening or resistant hypertension (ie needs >3 drugs); young age: patient aged <20 years, or <30 years needing treatment.
  • Therapeutic problems: multiple drug intolerance or contra-indications, persistent non-compliance or treatment refusal (the reluctant hypertensive).
  • Special situations: hypertension in pregnancy,[6] unusual BP variability.

For a full discussion on CVD risk assessment, treatment thresholds and their modification dependent on target organ damage and concurrent diseases, see separate related article Management of Hypertension.

Further reading & references

  1. Wolf-Maier K, Cooper RS, Kramer H, et al; Hypertension treatment and control in five European countries, Canada, and the United States.; Hypertension. 2004 Jan;43(1):10-7. Epub 2003 Nov 24.
  2. Health, social care and lifestyles: Chapter 3 - Hypertension - Health Survey for England (2011); Health and Social Care Information Centre
  3. Hypertension: management of hypertension in adults in primary care; NICE Clinical Guideline (August 2011)
  4. Guidelines for the management of arterial hypertension; ESH/ESC Clinical Practice Guidelines, European Society of Cardiology (2013)
  5. Lewington S, Clarke R, Qizilbash N, et al; Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet. 2002 Dec 14;360(9349):1903-13.
  6. Hypertension in pregnancy; NICE Clinical Guideline (August 2010)
  7. Stergiou GS, Nasothimiou E, Giovas P, et al; Diagnosis of hypertension in children and adolescents based on home versus ambulatory blood pressure monitoring. J Hypertens. 2008 Aug;26(8):1556-62.
  8. Falkner B; Hypertension in children and adolescents: epidemiology and natural history. Pediatr Nephrol. 2009 May 7.
  9. He FJ, Li J, Macgregor GA; Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ. 2013 Apr 3;346:f1325. doi: 10.1136/bmj.f1325.
  10. Ezzati M, Lopez AD, Rodgers A, et al; Selected major risk factors and global and regional burden of disease. Lancet. 2002 Nov 2;360(9343):1347-60.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Hayley Willacy
Current Version:
Peer Reviewer:
Dr Helen Huins
Document ID:
2289 (v26)
Last Checked:
17/12/2013
Next Review:
16/12/2018