Stages and grades of essential hypertension
The diagnosis is formulated taking into account the stage (assessing target organ involvement) and grade (blood pressure values).
Stages of target organ damage:
- Stage II: Blood pressure is elevated, objective changes in target organs are documented (e.g., left ventricular hypertrophy), but their function is not impaired.
- Stage III: Blood pressure is elevated, with present functional impairment of target organs (heart or renal failure, strokes).
Grades of blood pressure elevation (WHO/ISH 1999):
- Grade 1 (mild): 140–159 / 90–99 mm Hg
- Grade 2 (moderate): 160–179 / 100–109 mm Hg
- Grade 3 (severe): >180 / >110 mm Hg
- Isolated systolic hypertension: >140 / <90 mm Hg
Mechanisms of development (pathogenesis)
It was previously believed that the main cause was stress and neurogenic factors. Modern medicine takes a multifactorial approach.
Key hemodynamic factors determining blood pressure levels:
- Cardiac output (minute volume of blood).
- Total peripheral vascular resistance (TPVR).
Blood pressure can increase via a hyperkinetic type (increased cardiac output), hypokinetic type (increased TPVR with low output), or eukinetic type (regulatory failure with normal parameters).
An important role is played by the kidneys. They regulate fluid volume and secrete hormones. Activation of the renin-angiotensin-aldosterone system (RAAS) leads to the formation of angiotensin II (a potent vasoconstrictor) and the release of aldosterone (which retains sodium and water). In addition, genetic defects can impair sodium and calcium ion transport, causing a tendency for blood vessels to spasm and undergo mechanical narrowing due to wall edema.
Target organs and complications
Long-term arterial hypertension affects specific organs, causing structural and functional changes.
- Heart: Left ventricular hypertrophy develops. The risk of coronary artery disease (angina, myocardial infarction) increases, and heart failure develops (even without ventricular dilation, due to impaired relaxation).
- Kidneys: Nephroangiosclerosis forms, glomerular filtration rate decreases, and microalbuminuria appears. In the end stage, chronic renal failure occurs.
- Brain: Risk of thrombosis, hemorrhages, and lacunar infarctions. This leads to encephalopathy and strokes.
- Blood vessels: Retinal arteries are affected (spasm, sclerosis, hemorrhages), along with the carotid arteries and aorta. Fundoscopic examination is the only way to visually assess the state of microvessels.
Principles of Diagnosis and Treatment
To confirm the diagnosis, at least two measurements at two doctor visits are required (with an interval of 2 months after the first). 24-hour ambulatory blood pressure monitoring (ABPM) is used to rule out "white-coat hypertension" and assess the nocturnal blood pressure profile (normally, blood pressure drops by 10–20% at night).
Treatment: Non-pharmacological therapy is mandatory (weight loss, salt restriction to 2–25 g/day, alcohol cessation).
Pharmacological therapy is lifelong. Treatment begins with minimum doses (monotherapy); if ineffective, the drug class is changed or combinations are used (e.g., ACE inhibitor + diuretic). Preference is given to 24-hour-acting drugs (once daily administration). Main classes: diuretics, β-blockers, ACE inhibitors, calcium channel blockers, centrally acting agents.
Briefly: answers to topical questions
What are the stages of essential hypertension depending on target organ damage?
Depending on target organ damage, three stages of essential hypertension are distinguished.
- Stage I is characterized by elevated blood pressure, with an absence of organic changes in the cardiovascular system.
- Stage II is determined by the presence of objective changes in target organs (retinal vessels, brain, heart, kidneys), but organ function remains unimpaired.
- Stage III is diagnosed when arterial hypertension is combined with target organ damage and the mandatory presence of impaired function in these organs (e.g., development of heart or renal failure, vascular events).
Class and exam questions
What is "white-coat hypertension"?
This is a phenomenon in which a patient's blood pressure rises only during a doctor's appointment due to stress, while remaining normal at home. It is detected using ABPM.
Can pills be stopped if blood pressure has normalized?
No, drug therapy must be lifelong and continuous. Blood pressure normalization is achieved precisely through medications; only careful dose adjustment by a physician is possible.
Why is the eye fundus examined in hypertension?
Funduscopy allows the doctor to directly view the small retinal vessels. Their changes (spasm, sclerosis) reflect the state of microcirculation throughout the body, including in the kidneys and brain.
What else to study on this topic
- Pathogenetic mechanisms at the vascular wall level (ionic imbalance and edema)
- Instrumental diagnostics: signs of LVH on ECG and echocardiography
- Metabolic syndrome in essential hypertension
- Hypertensive crisis: causes, clinical presentation, management algorithm
- Balance of vasopressor and vasodepressor systems
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