(Jrt)
Hypertension
Epidemiology
The statistics are difficult to establish because they relate primarily if not exclusively, patients treated.
In the world
In 2000, an estimated 26.4% in the proportion of hypertension (26.6% men and 26.1% women) and 29.2% should be achieved by 2025 (29% men and 29.5% of women). Among the 972 million adults with hypertension, 333 million, or 34.3%, from countries "developed", and 639 million, or 65.7%, come from "developing" countries, which shows a prevalence much strongest of hypertension among developed countries. The number of adults with high blood pressure by 2025 could increase by 60% to 1.56 billion.
High blood pressure is responsible for just under 8 million deaths per year worldwide and nearly 100 million days of disability. It would be the cause of almost half of stroke and heart accidents.
Definition
Blood pressure should be measured sitting or lying, after 5 to 10 minutes of rest. The values must be recovered amounted to three different occasions so that we can speak with hypertension (HTA). The doctor measure two numbers:
* The systolic blood pressure or PAS, which reflects the pressure during the contraction of the left ventricle (systole)
* Diastolic blood pressure or PAD, which reflects the pressure during relaxation of the left ventricle (diastole)
* A blood pressure average is calculated from the first two.
The measures speak centimeter or in millimeters of mercury (Hg). Blood pressure is considered high blood pressure prior to the values of systolic blood pressure between 120 and 139 mm Hg and / or diastolic blood pressure between 80 and 89 mm Hg.
The concept of hypertension limit no longer exists.
* If increased values are found occasionally, one speaks of labile hypertension, which then requires a simple oversight, possibly accompanied by measures hygiénodiététiques.
* There is talk of white coat effect if the tension is high in the doctor's office and normalcy in the everyday life. This increased pressure is secondary to the stress of consultation and is not abnormal. This effect would almost a quarter of patients diagnosed with hypertension.
* On the contrary, we talk about HTA hidden when the figures are normal tensionnels the doctor's office and they are high otherwise.
This definition of hypertension is based on the acceptability of a risk rather than on a normal value.
High blood pressure is not a disease but represents a risk factor which, if it is handled, can be avoided, to some extent, complications.
The risk increases with high blood pressure and it is desirable to have tensonniels figures as low as possible. However, the World Health Organization (WHO) has set limits, taking into account both the risks tensionnels and disadvantages associated with treatment.
A voltage is therefore regarded as normal:
* If the systolic blood pressure is less than 140 millimeters of mercury (Hg)
* And if diastolic blood pressure is less than 90 mm (Hg)
A hypertension is called "resistant" if it remains high despite the hotel concomitantly three-hypertensive drugs. It concerns 20 to 30% of HTA.
Causes
1. In 90% of cases, hypertension is called essential: no known cause can be found in this case.
2. In 10% of cases, hypertension is secondary: Several causes may be the cause of hypertension, some of which are curable permanently.
Causes kidney: 4%
1. Renal (secondary to polycystic kidney disease, glomerulonephritis, a pyelonephritis, etc.)..
2. Affection unilateral renal non-vascular (pyelonephritis unilateral tuberculosis, congenital hyperplasia).
3. Stenosis of the renal artery (atheroma or fibrosis). It follows a hypoperfusion renal parenchyma of the affected side, with the consequence, an increase of activity of the renin - angiotensin - aldosterone, causing water retention and salt and a vasoconstriction of the arteries.
Causes adrenal
1. The pheochromocytoma. It is a tumor secreting excess of catecholamines. These substances increase the heart rate, the strength of contraction of the heart and cause a vaso constriction of the arteries, these three elements lead to increased numbers tensionnels. The tumor, mostly adrenal, however, may have other locations. The symptoms involve, the advanced tensionnelles, headaches, sweating and palpitations. The diagnosis is possible by the bioassay derivatives of catecholamines, including acid vanylmandélique, in blood or urine. The scanner or adrenal scintigraphy can locate the tumor (diagnosis topographic).
2. Cushing's syndrome (a tumor or a bilateral adrenal hyperplasia) causes a significant cortisol secretion or its derivatives. The signs are usually evocative: érythrose (red) face ...
3. Conn's syndrome leads to a secretion of aldosterone excess, causing water retention as a result of sodium retention, and a leak of potassium. The guiding the diagnosis is the finding of hypokalemia (lower rate of potassium in the blood). This hyperaldostéronisme, dosable in blood and urine, is said primary because it is not due to the increase in renin (normal or low rates of the latter in the blood). He opposes the hyperaldostéronismes secondary (high renin and aldosterone) as seen in cases of stenosis of a renal artery.
The poisoning by the glycyrrhizine
The glycyrrhizine or licorice comes from the root of the liquorice. It acts on the inhibition of an enzyme, 11 β-hydroxysteroid dehydrogenase (type 2), normally present in certain kidney cells to metabolize cortisol to cortisone to allow aldosterone regulate the reabsorption of sodium on its receptor (mineralocorticoid receptor). In inactivating action by the 11 β-hydroxysteroid dehydrogenase (type 2), licorice allows the permanent activation of the receptor for aldosterone by cortisol, and an unregulated reabsorption of sodium. Too much licorice reproduced the picture of a adenoma Conn. The poisoning is secondary to the abundant consumption (more than one gram per day of glycyrrhizine) based beverages liquorice (mostly pastis without alcohol) or solid (licorice sticks ...).
The aortic coarctation
The shrinkage congenital (birth) of the junction between horizontal and aorta descending aorta (aortic isthmus) results:
1. an increase in blood pressure upstream of the shrinkage, particularly in terms of both arms,
2. a decrease in blood pressure downstream, manifested by femoral pulse hard or not perceptible.
This diagnosis is systematically to refer to any hypertension of the child.
Pregnancy
High blood pressure, occurring in a pregnant woman is called hypertension pregnancy. The precise mechanism is unclear, but makes use of hormonal phenomena and probably immuno-allergic.
Other causes
1. endocrine: hyperthyroidism, hypothyroidism, acromegaly, hyperparathyroidism and causes adrenal already mentioned above.
2. Drug: steroids and hormones
3. A brain tumor or stroke.
Causes favorisantes
In the vast majority of cases, the precise mechanism of hypertension is unknown. However, we can determine a number of circumstances associated statistically with hypertension. This is called a risk factor. This term implies that causation is not established (only statistical risk). The frequent coexistence among these factors in the same patient, in fact, a multifactorial disease.
The age
Blood pressure increases with age. This increase is continuing for systolic, while the diastolic lowered after the sixties, probably by a mechanism rigidification of the arteries. Thus, less than 2% of subjects under the age of 20 are hypertensive, even though they are more than 40% after 60 years.
The sex
The level tensionnel men is higher than that of females up to 50 years, then there's inversion beyond.
Heredity
There is a genetic determinism of essential hypertension, whose nature composite was highlighted.
The food (including excess salt)
* The most studied was the consumption of edible salt (NaCl) whose importance could, if triggered, at least maintain an HTA. Excessive salt would be responsible for 25 000 deaths per year in France (75 000 cardiovascular events). The sodium ion (Na +) play an essential role in susceptibility to salt hypertension. The report sodium / potassium could be a determining factor. In any case, the reduction in consumption of sodium chloride (30 to 35% over 30 years) in Finland seems a major factor in the decline of more than 1 percentage point blood pressure average population, and thereby the fall of over 75% of cardiovascular mortality in people under 65, and increased life expectancy of 6 to 7 years. Other authors attribute an equally important role in the ion chlorine (Cl-) or even, in certain forms of hypertension, calcium ion (Ca + +).
* The consumption of alcohol leads to a chronic increase in the level tensionnel. The big drinkers have elevated systolic pressure of more than 1 cm Hg, on average, compared to non-drinkers.
* The consumption of polyunsaturated fatty acids has an inverse relationship with the level tensionnel.
* The consumption of coffee is accompanied by an increase in tension but the effect is minimal due to the development of tolerance to caffeine.
* The consumption of licorice, see poisoning by the glycyrrhizine above.
The weight
There is a strong correlation between body mass index (an indicator of overweight, bringing the weight to height) and the level tensionnel.
In contrast, a diet with an obese hypertensive accompanied by a decrease in tension.
Diabetes
The subjects were diabetic, on average, a blood pressure higher than in the rest of the population.
Stress
An acute stress is accompanied by an increase in transitional tension. A chronic stress, or rather, some ways in which the individual responds to a chronic stress, seems to promote a sustainable rise in blood pressure.
The physical exertion and physical inactivity
Increasing numbers tensionnels the effort is a physiological reaction acute quite normal.
Conversely, the chronic effect of an adapted physical training is usually accompanied by a lowering of blood pressure at rest. A lower blood pressure in the subject resulted in a report on sedentary is generally recognized.
Other factors
* The noise causes a rise in blood pressure.
* The altitude: those living at high altitudes have tensionnel a level lower than those living at sea level
* The season: blood pressure is higher in winter.
* Sleep: ronfleurs subjects are twice as often hypertension than non-ronfleurs.
* The estro-progestin pill increases the figures tensionnels.
Events
Many hypertensive patients have no symptoms and hypertension is then discovery of a systematic review or consultation motivated by something else.
In some cases, symptoms may reflect the impact of raising tension on the body. Although not specific, the main symptoms that may be encountered during a hypertension are:
* Headache (headache): they are particularly characteristic of severe hypertension. They are typically present in the morning, in the occipital region (neck and above)
* Tinnitus (whistling hearing), phosphenes (perception of light dots)
* Dizziness,
* Palpitations (sensation of increased heart rate)
* Asthenia (feeling tired),
* Dyspnea (difficulty breathing),
* Epistaxis (nosebleeds),
* Hematuria (presence of blood in the urine).
Signs may be characteristics of a causal affection (Cushing's disease, pheochromocytoma ...), for example: headache (headache), sweating, palpitations in the pheochromocytoma. In other cases, symptoms encountered are the result of a complication.
Complications
If hypertension is not controlled by treatment, complications can occur. It is important to note that hypertension itself is not a disease: it is a factor encouraging. In other words, its existence is neither necessary nor sufficient to see the diseases develop in the individual. On the scale of a population, hypertension is an issue of major public health. On the scale of an individual, it has a relatively low predictive value on the development of vascular problems.
They can be:
* Consequence "mechanical" blood pressure increased on vessels (rupture of the latter with bleeding)
* Consequence "mechanical" on the heart pump working at high pressures for a long time;
* The result of participation in the training or the growth of atheroma, obstructing more or less gradually arteries.
They are especially cardiac, neurological and kidney.
Complications heart
The additional workload imposed on the heart because of increased blood pressure leads to hypertrophy (increase) left ventricular very early, can be detected by ECG or ultrasound heart. This may regress hypertrophy in an antihypertensive treatment.
More belatedly, cavities heart expands and the contractile function of the myocardium (heart muscle) deteriorates, then showing signs of heart failure.
In addition, the attainment of atherosclerotic coronary as well as the increased needs oxygen of a heart enlarged explain the frequent occurrence of coronary insufficiency in hypertensive patients.
The HTA facilitates the formation of atherosclerotic plaque, which is broken when it forms a thrombus (clot), which can come stay at a coronary. The coronary will then be blocked and the area irrigated by cardiac normally it will gradually nécroser is myocardial infarction.
Complications neurological
The retinal changes may be observed at the bottom of eye, which helps monitor the vascular linked to hypertension: spasms, narrowing of arterioles, the emergence of exudates or hemorrhages, papilloedema ...
A breach of the central nervous system is common. It manifests itself in particular by the possible occurrence:
* A haemorrhagic stroke, a rupture of a cerebral vessel, or ischemic by obstruction of an artery by atheroma or a thrombus (a result of the rupture of a plaque of atheroma).
* A hypertensive encephalopathy (severe hypertension, disorders of consciousness, with papilloedema retinopathy, seizures), when HTA to very high figures;
* Dementia artériopathique in violation of diffuse brain arteries by atheroma.
Complications kidney
At the level of the kidneys, blood pressure is responsible for a nephro-angiosclérose and promotes the occurrence of renal failure. The impaired renal function is often very early and moderate, but is likely to worsen progressively.
Read also Nutrition
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