Arterial Hypertension – Etiology and Pathogenesis

Basic Questions on The Arterial Hypertension


What are the components formed vascular tone?

In Arterial Hypertension – The neurogenic component of vascular tone is determined exclusively by the tonic activity of sympathetic adrenergic vasoconstrictor nerve fibers (sympathetic and parasympathetic cholinergic vasodilator fibers have no tonic activity). It is considered established that under conditions of physiological rest, tonic sympathetic vasoconstrictor impulses do not exceed 1 – 2 impulses / s. However, electrophysiological studies show that efferent sympathetic impulses at rest have an irregular character, with non-periodic alternation of individual impulses and bursts of impulses, with different distances between impulses, with a different number of pulses in bursts and in frequency, therefore, can significantly exceed 1 – 2 pulses / s.

 

What are the main pressor substances which increase the basal vascular tone?

The basal tone is most pronounced in the vessels of organs with a high level of metabolism in the vessels of the kidneys, heart, and brain. It is influenced by humoral factors. Cell metabolites carbon dioxide, organic acids reduce basal tone and dilate blood vessels, and vasopressin, angiotensin,  adrenaline, circulating in the blood, increase the basal tone and the vessels narrow. Due to the presence of basal tone and its ability to local self-regulation, the vessels of these areas can maintain the volumetric blood flow rate at a constant level, regardless of fluctuations in systemic arterial pressure.

 

What depressor substances can disrupt vascular tone?

the tone of the blood vessels will be disturbed, which, to a greater or lesser extent, will cause the cardiovascular system to suffer. For example, arterial hypertension or TBI (the tone of peripheral vessels is increased) can cause a decrease in the tone of the cerebral vessels (veins) and the development of primary venous dystonia of the GM as a result (cases, when the venous outflow from the GM is impaired, is considered a secondary form of the disease). This is how difficult it is to figure out where the cause is and where the effect is … A vicious circle.

Its cause is often the failure of autonomic nervous activity, which must participate in the regulation of vascular tone. In such cases, the blood flows through the peripheral vessels slowly, in a timely manner, and in full to reach the vessels of the head in order to provide the brain with food. Very often, the activity of the ANS and the tone of the blood vessels does not keep pace with the growth of the body in adolescents. Decreased vascular tone in children with or without NCD often has clinical manifestations of fainting, so orthostatic collapse in adolescents is not considered such a rare phenomenon.

 

What is the vasomotor component of vascular tone? What factors affect it in pathology?

Tension of the vascular wall, which persists after complete denervation of the vessels. This indicates that besides the nervous system, there are other vasomotor mechanisms. Basal tone is regulated by the effects of vasoactive tissue metabolites, endothelial factors, biologically active substances and hormones. In addition, the so-called myogenic regulation plays an important role.

Endothelial regulation of vascular tone is carried out due to the production of biologically active substances with vasomotor activity by endothelial cells. The endothelium produces compounds with a dilatatory and constrictor effect on the tone of resistive vessels. The most important endothelial vasodilator is nitric oxide.

 

What causes hypertension – pathology resistive or capacitive vessels?

Distinguish between primary ( essential ) arterial hypertension (or hypertension) and secondary (symptomatic) arterial hypertension. Primary arterial hypertension develops as an independent chronic disease and accounts for up to 90% of cases of arterial hypertension. In hypertension, high blood pressure is the result of an imbalance in the regulatory system of the body.

Symptomatic hypertension accounts for 5 to 10% of hypertension cases. Secondary hypertension is a manifestation of the underlying disease:

  • kidney diseases ( glomerulonephritis , pyelonephritis, tuberculosis , hydronephrosis , tumors, renal artery stenosis );
  • pathology of the thyroid gland ( thyrotoxicosis );
  • diseases of the adrenal glands ( pheochromocytoma , Itsenko-Cushing’s syndrome , primary hyperaldosteronism);
  • coarctation or atherosclerosis of the aorta, etc.


What is hypertension?

Hypertension is a pathology of the cardiovascular apparatus that develops as a result of dysfunction of the higher centers of vascular regulation, neurohumoral and renal mechanisms and leads to arterial hypertension, functional and organic changes in the heart, central nervous system and kidneys. Subjective manifestations of high blood pressure are headaches, tinnitus, palpitations, shortness of breath, pain in the heart, veils before the eyes, etc. Examination in hypertension includes monitoring of blood pressure, ECG, echocardiography, ultrasonography of the arteries of the kidneys and neck, urinalysis and biochemical parameters blood. When the diagnosis is confirmed, the selection of drug therapy is made taking into account all risk factors.

 

What is symptomatic hypertension?

In some cases, the diagnosis of hypertension is mistaken, and patients receive long-term and unsuccessful treatment. Such patients lose the chance for prompt and productive treatment and risk numerous complications. This diagnostic error indicates an incorrect examination of the patient, in which the true cause of the rise in blood pressure to high numbers was not determined. In approximately 10-15% of cases, the cause of pressure surges is symptomatic arterial hypertension caused by various diseases of the organs involved in the regulation of blood pressure.

This condition occurs in 20% of people in the group of patients with malignant hypertension, which does not respond well to conventional treatment regimens. Symptomatic (or secondary) arterial hypertension is not an independent disease, and modern medicine knows about 70 diseases that can provoke this symptom.

 

List the main types of symptomatic hypertension.

  1. Renal hypertension (renovascular and renoparenchymal)
  2. Endocrine hypertension
  3. Drug hypertension
  4. Neurogenic hypertension
  5. Hemodynamic hypertension
  6. Toxic hypertension
  7. Stress hypertension

 

What hypertension is called regional?

 

 

 

List the “risk factors” explaining the acceleration of cardiovascular disease?

Risk factors for CVD are divided into:

  1. Modifiable, that is, which we can influence and eliminate
  2. Non-modifiable – which cannot be influenced. These are gender, age, racial and hereditary predisposition.

Non-modifiable CVD risk factors:

  • Gender: before the age of 50–55, men are more likely to develop angina pectoris than women.
  • Age. In men, the risk of cardiovascular disease increases after 45 years, and in women after 55 years.
  • Race: residents of Europe (Scandinavian countries), suffer from angina pectoris and arterial hypertension several times more often than people of the Negroid race.
  • Heredity. If a relative of a patient in the male line (first line of relationship) suffered a myocardial infarction or died of sudden cardiovascular death before the age of 55, and on the female side before the age of 65, then there is a high probability of developing angina pectoris.

Modifiable risk factors for CVD:

  • Obesity
  • Smoking
  • increase in blood glucose levels
  • Emotional stress
  • Physical inactivity
  • Arterial hypertension
  • Dyslipidemia
  • Increased blood clotting

 

At what phase of traumatic shock may occur high blood pressure? Why?

In the erectile phase – The muscles are tense. General hyperesthesia is noted, skin and tendon reflexes are increased. Breathing is quickened, uneven. The pulse is tense, blood pressure periodically rises, which is due to the release of the “emergency hormone” – adrenaline. It was noted that the more pronounced the erectile phase of shock, the more severe the torpid phase usually proceeds, and the worse the prognosis.

 

What determines the magnitude of blood pressure?

The difference between the maximum and minimum pressure values is called pulse pressureNormal blood pressure figures are in the range from 100/60 to 140/90 mm Hg. Art. The amount of blood pressure depends on a number of factors: cardiac output, blood volume, and peripheral vascular resistance.

Blood pressure increases with increased cardiac output, peripheral vascular resistance, the volume of blood, the viscosity of blood, and rigidity of vessel walls. Blood pressure decreases with decreased cardiac output, peripheral vascular resistance, the volume of blood, the viscosity of blood, and the elasticity of vessel walls.

 

What risk factors favor the development of resistant Arterial hypertension?