Hypertension

Synonym: High blood pressure German: Hypertonie, Hypertonus, Bluthochdruck

There are three different forms of hypertension:

• Arterial hypertension (increased blood pressure in body circulation)
• Pulmonary hypertension (increased blood pressure in lung circulation)
• Portal hypertension (increased blood pressure in portal venous system)

For most, the term Hypertension generally denotes arterial hypertension, which is the type discussed here.

	Table of contents
	1. Definition 2. Epidemiology 3. Classification 3.1. Classification according to cause 3.2. Classification according to ESH 3.3. Classification to WHO 3.4. Other classifications 4. Pathogenesis 5. Symptoms 6. Diagnostics

Definition

According to the WHO criteria, a systolic blood pressure higher than 120 mmHg or a diastolic blood pressure higher than 80 mmHg are borderline values, and a systolic blood pressure higher than 140 mmHg or a diastolic blood pressure higher than 90 mmHg is defined as hypertension.

Epidemiology

The prevalence of arterial hypertension is relatively high in the western industrial countries. The specifications of several epidemiological studies however partly clearly vary from one another. A study conducted in 2003 in 6 European countries, Canada and the USA stated the prevalence of hypertension among 44% of the population above 35 years of age in Europe. A prevalence of 28% is stated for the USA. As a rough approximation, it may be said that, of the population in Europe,

• 20-30% in the age group of 45-54 years,
• 30-40% in the age group of 55-64 years, and
• 40-50% in the age group of 65-74 years

suffer from high blood pressure.

Classification

The arterial hypertension may be classified according to many different aspects, which are partly pathophysiological and partly clinically affected.

Classification according to cause

Primary hypertension: A hypertension that develops without any identifiable causes. It is also termed essential hypertension. It accounts for an overwhelming share of hypertension cases (approx. 85%).

Secondary hypertension: A hypertension that occurs as a consequence of another primary disease and/or triggered by verifiable factors. The secondary hypertension accounts for the smaller share of cases (approx. 15%). Potential causes are:

• Kidney diseases ("renal hypertension")
• Endocrine disorders ("endocrine hypertension")
  • Hyperthyreosis
  • Hyperaldosteronism (Conn’s syndrome)
  • Hyperparathyroidism
  • Acromegaly
  • Cushing’s syndrome
  • Pheochromocytoma and many others.
• Vascular diseaseso
  • Aortic isthmus stenosis
  • Vasculitis
  • Collagenosis
  • Renal artery stenosis
• Tumors (renin-producing tumors, brain tumors)

Not classified as chronic arterial hypertension are temporary increases in blood pressure, which are triggered by, among others, the following causes:

• Medicaments (corticosteroids, cyclosporin, erythropoietin, adrenalin)
• Drugs (alcohol, cocaine, amphetamine)
• Poisoning (carbon monoxide)
• Pregnancy (see: Pregnancy-induced hypertension (PIH)

Classification according to ESH

The ESH classifies the hypertension according to the extent of the blood pressure value:

	Classification according to ESH
	Grade Systolic RR Diastolic RR Grad 1 (mild) 140-159 mm Hg 90-99 mm Hg Grad 2 (moderate) 160-179 mm Hg 100-109 mm Hg Grad 3 (severe) >180 mm Hg > 110 mm Hg

Classification to WHO

According to the recommendations of the WHO hypertension is classified depending on the damages to blood vessels, eyes, heart, kidneys, etc.:

• Grade I: Hypertension without damages to the end organ
• Grade II: Hypertension with damages to the end organ (e.g.. fundus hypertonicus (Grade I and II), plaque formation in the larger blood vessels)
• Grade III: Hypertension with manifest cardiovascular secondary diseases (e.g. angina pectoris, heart attack, stroke, PAVK)

Other classifications

• Form of blood pressure increase
  • Isolated systolic hypertension
  • Isolated diastolic hypertension
  • Combined systolic-diastolic hypertension
• Time-dependent hypertensiono
  • Labile hypertension (borderline hypertension)
  • Stable hypertension (continuous hypertension)

Pathogenesis

The pathogenesis of primary hypertension is so complex that it could not be completely clarified so far. One reason is that the blood pressure is influenced by many diverse factors. Among others these are the circulating blood volume, the blood viscosity, the cardiac output, the blood vessel elasticity, the blood vessel width, and the hormonal (renin) and neuronal stimulation of the blood vessel tonus.

Symptoms

Hypertension appears mostly asymptomatic and in case of moderately high blood pressure values often causes only uncharacteristic ailments:

• Headaches (especially in the morning in bed)
• Dizziness
• Epistaxis (nosebleeds)
• Abnormal fatigue

In case of very high blood pressure the following can appear:

• Severe dyspnea
• Angina pectoris
• Palpitation
• Nausea
• Impaired vision

If the hypertension is not diagnosed by a blood pressure checkup, it often becomes noticeable only by late damages.

Diagnostics

The diagnosis of “hypertension� is primarily conducted by the repeated blood pressure measurement in both arms. The basic program for hypertension diagnosis further includes:

• Anamnesis (general symptoms, medicaments, nicotine, coffee, alcohol, drugs)
• Family anamnesis (heart attack, stroke)
• Auscultation (heart, arteria carotis in particular, abdomen)
• Ophthalmoscopy (ocular fundus)
• Laboratory
  • Urine status
  • Serum electrolytes
  • Creatinine clearance
  • TSH
  • Screening of cardiovascular risk factors (e.g.. cholesterol, blood sugar)
• ECG
• Echocardiography Links