In general, a specific causes of high blood pressure or hypertension cannot be detected in the vast majority of patients. When arterial hypertension (AHT) has no apparent cause, it is called Essential Hypertension. In studies performed at the Health Centers around the world, secondary AHT, that is, with detectable cause, is usually less than 5%. However, in certain big hospitals receiving more severe patients, this percentage is higher.
For this reason (95% without identified cause), it is neither appropriate or desirable, nor even possible, to investigate the cause in all individuals with hypertension. However, in selected cases, especially those who are resistant to therapy, severe cases and young hypertensive patients, or in which any clinical suspicion is raised, should be investigated in order to detect curable causes of hypertension. Because in these cases, cure of the disease is possible, hence tests to investigate the cause of hypertension should therefore be performed if there are suspicious signs or symptoms.
ESSENTIAL ARTERIAL HYPERTENSION
Today hypertension is thought to be due to a combination of hereditary, environmental factors and lifestyle errors. We must not forget that the hereditary factors are not modifiable, but the lifestyle is. The adoption of a healthy lifestyle is not only beneficial in terms of prevention and control of hypertension, but also of several other noncommunicable or chronic diseases (cancer or diabetes) and health in general.
There is a whole set of lifestyle mistakes that conditions, in susceptible individuals, the onset and / or aggravation of hypertension or its complications.
RISK FACTORS FOR HYPERTENSION
Excess salt consumption:
In modern societies, salt is consumed exaggerated, far above our needs, which is why it is currently considered one of the great rogues of public health. Excessive sodium intake is linked to an increased incidence of hypertension, which in turn increases the risk of cardiovascular disease and kidney damage. Excessive and unnecessary salt consumption is thought to contribute to the development of hypertension in industrialized countries. People that do not consume salt do not suffer from hypertension.
Excess body weight:
Hypertension is much more common in overweight and obese individuals and is associated with other cardiovascular risk factors in these individuals. It is estimated that a reduction of 5 kg in body weight is accompanied by a decrease in blood pressure from 10 mmHg to systolic pressure and from 5 mmHg to diastolic. This descent allows the control of most mild hypertensive individuals.
It is known today that three or more glasses of wine (or the equivalent in other alcoholic beverages) contribute to raise blood pressure. It is well demonstrated that when alcohol consumption is reduced, blood pressure drops.
Regular exercise lowers blood pressure by about 10-15 mm Hg (millimeter of mercury). Physical activity provides other benefits such as helping to control weight, reduce tension caused by stress, conditions deeper sleep, better disposition and raise HDL (good cholesterol).
Smoking increases blood pressure and exacerbates the harmful effects of hypertension on the walls of the arteries, accelerating atherosclerosis. There are studies showing that, in cases of mild and moderate hypertension, the benefit obtained from smoking cessation is even higher than that of the antihypertensive drug therapy itself.
SECONDARY ARTERIAL HYPERTENSION
The causes of secondary hypertension, although relatively rare, are of great importance because they are potentially curable. They are the identifiable causes of high blood pressure.
Following are the most important causes:
Sleep apnea is a very common and sometimes devalued clinical condition. It is characterized by recurrent episodes of airflow arrest resulting from inspiratory airway collapse during sleep followed by decreased arterial oxygen saturation. The individual stops breathing momentarily during sleep due to airway obstruction. The relationship between sleep apnea and hypertension is due in large part to the fact that apnea permanently activates the sympathetic nervous system, which increases blood pressure.
Renal or Kidney disease
Renal artery stenosis is another cause of secondary hypertension. This is characterized by a decrease in the diameter of the renal artery, which will offer more resistance to the passage of blood thus raising blood pressure.
Not all renal diseases are associated with AHT, but they are the main cause of known secondary AHT, especially renal parenchymal diseases. Renal artery stenosis (narrowing) is a relatively rare cause, but if diagnosed, it can in many cases be cured surgically or, more recently, by angioplasty (dilation of the narrowed artery, with a catheter having an inflatable balloon in the coronary artery disease).
They are very rare cause of hypertension. The most frequent ones act through a hormonal production increased by the suprarenals, generally by a tumor that can be removed surgically, like for example, the primary Hyperaldosteronism, the Pheochromocytoma or even the Cushing’s syndrome.
Pheochromocytoma is a catecholamine-producing tumor (such as adrenaline and noradrenaline) that originates in a type of adrenal gland (chromaffin cells), accounting for about 0.2% of cases of secondary hypertension. This hypertension is due to the fact that catecholamines have positive effect on blood pressure.
Almost all women who take the oral contraceptive pills suffer a slight increase in blood pressure. In a small number of cases, such elevation may be considerable and lead to hypertension.
In the above given cases, AHT arises as a consequence of the diseases, however it may also be the result of the use of certain medications such as non-steroidal anti-inflammatory drugs or antidepressants.
The causes of secondary hypertension, although rare, are of great importance because they are potentially curable if detected early.