14. The importance of essential hypertension, epidemiology, diagnosis and treatment (+ HTN in general)

Page created on April 8, 2022. Last updated on April 20, 2022 at 13:59

Hypertension in general


Hypertension, elevated blood pressure in the arterial system, is not a disease but a risk factor for development of many diseases, most notably cardiovascular disease. It’s mostly asymptomatic.

Hypertension is a major cause of morbidity and mortality worldwide, and it’s also becoming more and more common. However, even small decreases in blood pressure in the case of hypertension cause large improvements in the risk for complications.


  • Primary (see below) (90% of cases)
  • Secondary (see topic 15)

Classification of severity

According to the European Society of Cardiology (ESC):

Severity Systolic blood pressure (mmHg) Diastolic blood pressure (mmHg)
Normal <140 <90
Grade 1 HTN 140 – 160 90 – 100
Grade 2 HTN 160 – 180 100 – 110
Grade 3 HTN >180 >110
Isolated systolic HTN >140 <90
Isolated diastolic HTN <140 >90

Special types

  • White-coat hypertension – hypertension in a clinical scenario (hospital, clinic) but not on ambulatory measurements
  • Masked hypertension – hypertension on ambulatory measurements but not in a clinical scenario
  • Treatment-resistant hypertension – uncontrolled blood pressure despite the use of 3 antihypertensive agents of different classes, where one is a diuretic.
  • Hypertensive crisis – an acute increase in blood pressure corresponding to grade 3 hypertension. It’s an umbrella term for two conditions, hypertensive urgency and hypertensive emergency.
    • A hypertensive urgency is a hypertensive crisis which is asymptomatic or only causes nonspecific symptoms like headache or dizziness.
    • A hypertensive emergency is a hypertensive crisis which causes end-organ damage to the heart, CNS, kidney, eye, etc.

Clinical features

Hypertension by itself is asymptomatic, but there may be findings of cardiovascular disease or renal disease. Severe hypertension may cause non-specific symptoms like headache.

Diagnosis and evaluation

The diagnosis of hypertension is not made after one measurement of elevated blood pressure. Proper diagnosis requires multiple measurements under standardised conditions at multiple consultations.

Ambulatory (24 hour) blood pressure monitoring (ABPM) involves wearing a blood pressure during a whole 24-hour period while the patient goes along with their life. It measures the blood pressure at fixed intervals of 15 – 60 minutes. ABPM can be used to confirm blood pressure readings and diagnose white coat and masked hypertension.

Home blood pressure monitoring (HBPM) requires patient training and proper equipment to be accurate.


  • CNS
    • Stroke
    • Hypertensive encephalopathy
    • Dementia
  • Heart
    • Acute myocardial infarction
    • Hypertensive cardiomyopathy -> heart failure
  • Kidney
    • Chronic kidney disease
  • Hypertensive retinopathy
  • Peripheral artery disease
  • Diabetes mellitus
  • Early death
  • +++

Primary hypertension

Introduction and epidemiology

Primary hypertension, previously called essential hypertension due to the false belief that it was essential to maintain perfusion in elderly, is a very prevalent condition. Hypertension occurs in >30% of the adult population.

Primary hypertension accounts for >90% of cases of hypertension.


The precise cause of primary hypertension is not known, but many risk factors are known:

  • Old age
  • Obesity
  • Increased salt intake
  • Family history


Many mechanisms are probably involved in development of primary hypertension:

  • Activation of renin-angiotensin-aldosterone system
  • Activation of sympathetic nervous system
  • Fluid and salt retention

Diagnosis and evaluation

Unless there are features to suggest secondary hypertension, newly diagnosed hypertension is managed as primary.


The blood pressure targets for treated hypertension are:

  • At least BP reduction by >20/10 mmHg, ideally to <140/90 mmHg
  • Optimally:
    • If <65 years: BP target <130/80 mmHg
    • If >65 years: BP target <140/90 mmHg, but consider higher targets individually

However, ESC has also published more detailed blood pressure targets depending on the presence of comorbidities as well.

There are several non-pharmacological interventions which are known to decrease blood pressure:

  • Achieve normal body weight (BMI 18 – 25)
  • Adopt DASH diet
  • Reduce dietary sodium (< 2,4 g/day, equal to 5 g/day of NaCl)
  • Increase physical activity
  • Decrease alcohol consumption
  • Smoking cessation

However, in many people, pharmacological treatments are necessary. The 2020 International Society of Hypertension (ISH) recommends the following:

  • First line: A single pill containing two antihypertensive drugs in low dose, ideally a RAAS blocker + calcium channel blocker
  • Second line: A single pill containing two antihypertensive drugs in higher dose, ideally a RAAS blocker + calcium channel blocker
  • Third line: Addition of diuretic (thiazide-like diuretic)
  • Fourth line (resistant hypertension): Addition of spironolactone

However, the choice of antihypertensive drug should also take into account other indications the patient might have. For example, if the patient has heart failure or angina, a beta blocker may be a better choice as antihypertensive because it treats both the heart condition and the high blood pressure.

Leave a Reply

Inputting your name is optional. All comments are anonymous.

This site uses Akismet to reduce spam. Learn how your comment data is processed.