The Asthma ( asthma Latin meaning “difficulty breathing”, is a disease affecting the respiratory system and upper airway including the two bronchi , defined as difficulty breathing at the end. The disease can be explained by three mechanisms General:

• inflammation with edema of the epithelium, bronchial;
• a bronchoconstriction ;
• Bronchial hyper-activity (chronic or not) as manifested by increased secretion of mucus , particularly due to a remodeling of the upper airway.

Historical

Asthma is one disease known since antiquity. Aretaeus, around the first century, mentions it in one of his books. Moses Maimonides the XII ^th century also mentions the disease.

The Treatise of the Asthma of John Floyer (1649-1734), published 1698 and is based in part on his own experience. Is the first medical textbook addressing fully asthma?

The French writer Marcel Proust was suffering from asthma since childhood, the disease affecting up to his work.

Epidemiology

In France, a national survey conducted by the National Health Insurance Fund (CNAM) in year 2007 on all patients 5 to 44 years treated for asthma, found that 900 000 people were receiving regular treatment with three or more prescriptions of asthma drugs. Of these 900 000 patients, 27%, mostly in the age group 20-29 years, had inadequately controlled asthma, requiring at least four times a year to use a medicine only intended to address the crisis. In France, there are approximately 15 000 hospitalizations per year for an asthma attack, and 1 000 deaths.

TYPES OF ASTHMA AND CLINICAL

The bronchi have a specific role in protecting the lungs from foreign agents or external aggression, including the restriction of the diameter bronchique.L asthma is characterized by an overreaction of the bronchi in relation to its environment. The airways of asthma are inflammatory and see their small diameter. The mucus produced in response to inflammation further reduces the diameter of bronchi, making it difficult expiration; we speak of expiratory airway obstruction. The causes of inflammation and especially its conditions of events can establish three main types of asthma.

Although each patient corresponds to one or other of the profiles of patients with asthma, it is only a general demonstration of the disease; it is not uncommon for chronic asthmatic crises to know asthma or allergy-induced asthma and vice versa.

In all types of asthma found the following symptoms:

• Difficulty breathing or shortness of breath;
• Oppression (respiratory sensation of heaviness on the chest)
• A tachypnea or conversely a bradypnea , that is to say an increase or a decrease in respiratory rate;
• A whistle at the end (talking about breathing sibilant);
• A decrease in saturation of the hemoglobin oxygen mainly in severe attacks;
• A tachycardia;
• A draw in the event of severe crisis;
• A cough may be chronic or dominate the night.

Crises that may occur after exercise (known as exercise-induced asthma or more precisely broncho-spasm post-exercise)

Only the intensity, duration and causes of these symptoms vary from one type to another.

ASTHMA CHRONIC

It is a chronic bronchial hyperactivity little subject to external agents. Chronic inflammation is often slow onset and progressive. Generally this since childhood and it can occur in the early years of childhood by repeated asthma attacks or bronchitis Chronic sibilants. In this case, it is a worsening of the asthmatic syndrome, which is a chronic (when it existed until this aggravation a trigger). Due to the slow onset and progressive inflammation, it may go unnoticed, especially because the patient has time to get used to the respiratory difficulties and gradually lose the notion of “normality” breathing until that the discomfort becomes too invasive in the patient’s life. Untreated this form of asthma usually develops in respiratory failure.

Although the actual causes remain to this day subject to discussion, a prevailing hypothesis is that this form of asthma is caused by an autoimmune reaction. That is to say that the patient’s immune system would attack its own lungs, thus maintaining the inflammation in time.

ALLERGIC ASTHMA

Generally characterized by the occurrence of one or more attacks caused by an overreaction of the bronchi of the patient to an outside agent (most often allergenic). This is the form most severe asthma in the short term, the degree of bronchial reaction may be particularly important and sometimes fatal.

The allergic asthma is manifested by a sudden blockage and rapid progression of bronchial voice, the patient in crisis choking suffocation (inability to breathe properly to prevent a new inspiration) and lack of oxygen in the blood (inability to breathe preventing oxygen (due to the inspiration) and saturating the body Co2).

This form of asthma may develop in chronic asthma, particularly if the allergen exposure is constant and long duration.

The asthma attack is always a medical emergency life-threatening and requires specific care.

ASTHMA EFFORT

This is manifested by an asthma attack occurring during physical exertion. The cause is defined as an effort traumatic for the bronchi. That is to say a special effort seeking the bronchi and / or conducted under conditions that make work more difficult bronchus. The effort is typically a cardio (requesting the cardiac system in particular so breathing). Environmental factors such as worsening of asthma, are the cold, wind and an environment with poor ventilation. The cold and wind, promoting airway inflammation, also promotes the crisis.

This type of asthma is often isolated or sometimes associated with chronic asthma or allergic complication of becoming a kind of induced asthma.

Asthma attacks could be facilitated by intense stress 4. Indeed, stress has the effect of increasing the heart rate and develops a syndrome of hyperventilation, facilitating or exacerbating asthma.

The crisis in asthma is also classified as follows:

The intermittent asthma, which is arbitrarily defined as the occurrence to a maximum of two brief seizures per week and / or two nightly episodes per month, and a PEF greater than 80%.

The persistent asthma is defined when more than two episodes per week and / or more than two nocturnal episodes per month, with impact on ongoing operations. It can be mild, moderate or severe.

The severe acute asthma that involves life-threatening. It requires urgent treatment in hospital (for example, in France about 2 000 people a year die from asthma or 3.2 cases per 100 000 inhabitants) 5. Clinically, there is at least one of the following signs:

• Unusual feeling of crisis;
• Difficulty speaking (spoke a word at a time)
• Cyanosis
• Increased heart rate (tachycardia CF> 120/min)
• Impaired consciousness (confusion, coma)
• “Auscultatory silence” (absence of breath sounds on auscultation);

A decrease in PEF ( peak expiratory flow or Peak Flow ) reduced by half compared with the best score of the patient, or from its theoretical value, the DEP is the only objective means of assessing the intensity of asthma

Resistance to treatment of the crisis (bronchodilator fast action);

A respiratory rate 25/mn adults, 30/mn in children over 5 years 50/mn among children 2 to 5 years, even with low breathing pauses in breathing

A hypotension

It is advisable to separate the asthma infants , defined by the appearance of at least three episodes of wheezing before the age of three years. Asthma in infants disappears usually before age five.

Recent Expansion Of Asthma

There has been a rapid expansion of the disease for 40 years in developed countries 6,7. It occurs mainly in countries with a high degree of industrialization, and industrialization in developing fast, it is little known example in sub-Saharan Africa. In 1999 researchers at the International Study of Asthma and Allergies in Childhood few have quantified data on asthma, by measuring the percentage of asthma and allergies among 13-14 year olds in different countries:

-       Sweden and Finland: between 10% and 20%;

-       Albania, Romania, Russia, Georgia and Uzbekistan: <6%;

-       United Kingdom:> 30% (asthma is the second leading cause of mortality)

• Monitoring the evolution of the incidence in France is conducted by the sentinel network of Inserm.

Diagnosis

-       Examinations of lung function or spirometry ;

-       Test reactivity to a bronchodilator (forced expiratory flow before and after salbutamol);

-       Bronchial provocation test.

-       Measurement of exhaled nitric oxide (diagnostic aid but also evaluating the effectiveness of treatment)

-

Treatment

Asthma Chronic

Steroids used to treat chronic inflammation, whereas the bronchodilator helps relieve the daily sick. The first line of treatment is a beta-2 agonist short duration of action.

Secondly just treatment by inhaled cortico-steroids (eg Flixotide is propionate fluticasone ) + beta-2 agonist short duration of action in a crisis.

Third if the consumption of beta-2 agonist short duration of action (Ventolin) inhaler more than a year (or 2 uses per week), should be treated with inhaled cortico-steroid + beta-2 agonist long-term action.

It is also recommended to monitor and possibly treat allergies with antihistamines . People with allergic asthma should avoid contact with the most common allergens (cat dander, dust, pollen, etc. …)

In recent years, emerged receptor antagonists of leukotrienes (eg montelukast , zafirlukast ).

The Asthma

The treatment is to administer a bronchodilator on salbutamol (known in France under the trade name of “Ventolin”) or terbutaline , causing a “relaxation” of the bronchial muscles and reopening of airways.

The administration is done mainly by inhalation aerosol dispensers or powders.  The technique of using MDIs must always be known by the patient for maximum effectiveness. The use of specific devices ” spacer “greatly facilitates the administration of metered dose inhalers, particularly in children but also adults.

Any crisis that does not yield quickly to the medication should be treated as a medical emergency.

The Acute

A transfer medicalized and hospital emergency are essential. The first line of treatment is based on a high-flow oxygen (6 to 8 liters / min), associated with the use of beta 2-stimulating short-acting inhaled at high doses, and administration of oral corticosteroids or IV 8. Indeed, the main risk here is asphyxiation.

Moreover, as in several cases of difficult ventilation, the permissive hypercapnia is an approach advocated by several authors.

The Therapeutic Management

Adapted in asthma crisis, it is based on the following steps before to prevent the occurrence but also the intensity of crises:

rehabilitation training ( adapted physical activity ) to push the threshold of exercise intensity causing the appearance of the broncho-spasm post-exercise; minimize ventilatory adaptation necessary for a given intensity (less shortness of breath during exercise) to fight against the reconditioning of a population that minimizes physical activities for fear of the crisis.

Act on the question of whether asthma is allergic, either by carrying out the eviction (= separation) of the allergen, or by attempting a desensitization to the allergen in question. The results are good with mites, pollen – less good with animals.

To prevent attacks, asthmatics can use a device (peak flow) to measure their peak expiratory flow, control of bronchial obstruction and tailoring their treatment outcome (taking acting bronchodilator Quick example, or change in treatment of substance in collaboration with the doctor.)

The method of thoracic manipulation called “Method Gesret” 9practiced in several countries since 1995.

Differential Diagnosis

See equivalent asthma, a disease associated speaking bronchial hyperresponsiveness, causing spasmodic cough and night, without causing clinically detectable decrease in the volume of air expired.

The Allergens And Pollution

In the early 1960s, has challenged the allergenic, mites and others. Hunting allergens result (using various products, possibly for most allergens) has assisted some patients.

The evolution of the correlation between asthma and allergy is not always symmetrical: this correlation has been demonstrated in Britain, but not in Germany or Italy, where the incidence of allergies has increased but not that of asthma 7. Which goes to prove that asthma could be intrinsic causes an autoimmune reaction or a genetic predisposition, although there have to date no studies proving it formally.

However, some studies tend to prove that asthma is also highly developed in areas subject to air pollution. In the early 1990s, it was shown that the particles of diesel in the air damaging the heart and lungs. Manufacturers have therefore changed the compression ratio of diesel engines and reducing the size of the volatile particles which damage the lungs now. A Dutch study clarifies the relationship between exposure to air pollutants and increased risk of asthma in children10.

Scientific studies show that air pollution is a cause of asthma 11, including VOC (volatile organic compounds) and NOx (nitrogen oxide: carbon monoxide, nitrogen dioxide) present both in the air in certain industrial cleaning or repair11.

To protect domestic pollution, asthma and allergies, doctors recommend regular ventilate her apartment, or use a device to purify the air of volatile microparticles 12or residues of pollutants or cleaning renovation, such as air purifier. The use of an air exchanger also reduces respiratory diseases in children13.

Moreover, the UFC Que Choisir has recently raised the issue of indoor air pollution and impacts of pollution in the interior spaces. In addition to NOx, VOC and dust in the air, polluting industrial products used for the renovation such as carpet glued polluting and whose impact on health was denounced by consumer organizations in the same way as industrial paints, adhesives and cleaning products as being directly responsible for asthma in children and the frail.

Tobacco

Stephen Holgate considers that the smoke of tobacco is by far the leading identified cause of asthma. He and his team have proven that tobacco smoke alters genes in lung cells of mice, and could cause genetic changes in the lungs of the fetus, making them vulnerable to asthma . The same could be true for the unhealthy diets and even paracetamol (a powerful antioxidant that has recently been linked to asthma).

Smoking both active and passive 14may be involved.

Since the 1990s, we began to focus on the lack of coexistence between humans and bacteria in countries particularly affected by the disease. So are put into question the “surhygiène” with its antibacterial cleaning products, as well as the widespread broad-spectrum antibiotics and routine vaccinations.

All leading to a lack of self-immunization by lack of exposure to surrounding bacteria. One wonders why, for example, in an Indian hospital a group of children from poor neighborhoods is afflicted with pneumonia and other infections, while the group of children from wealthy neighborhoods is suffering from asthma. This “hygiene hypothesis” is supported by evidence such as any occurrence of allergies in children living on farms and in contact with animals, those who are breast-fed non-pasteurized, or in the 3 th or 4 th or 5 th child of a family – who are exposed at a young age to all pathogens and other microorganisms that their elders can bring to school. Researchers are exploring the potential to cause the same response in the immune system of a child as that caused by infection with bilharzia parasites. On the other hand, the “hygiene hypothesis” justifies the climb more allergies than asthma, which does not necessarily go together (you can have one without the other, under one or more forms).

THE GENETIC

These last years researchers have demonstrated that the airways of patients with chronic asthma or are permanently altered by the disease, or – possibly – develops differently in the womb. Stephen Holgate, a researcher on asthma in Great Britain, published in the journal Nature the results of a five year research involving the gene ADAM33. This is the first gene discovered for asthma, and monitor how the muscle develops in the airways. Holgate also believe that environmental factors could influence things much earlier than previously thought in the development of the disease: they may influence the expression of genes in the developing fetus, thereby contributing to genetic modification favoring disease. Holgate and his team have already shown the alteration of the gene ADAM33 by tobacco smoke in cultures of mouse lung tissue.

In October 2005 they published a report showing that when tissues of asthmatic airways are inflamed, they produce a molecule called TNF alpha, or tumor necrosis factor alpha. But the gene ADAM33, involved in asthma, behaves very similarly to the gene ADAM17 responsible for the production of TNF-alpha. There is also this molecule TNF alpha in inflamed tissue of patients with other chronic respiratory diseases such as rheumatoid arthritis (?) Or Crohn’s disease. After six years of struggle with the pharmaceutical industry to perform these tests, Holgate was able to convince them to endorse an experience that goes against the general trend towards a disease asthma allergen. In October 2004, he and his team injected 15 volunteers with the etanercept , a soluble receptor for TNF-alpha, which intercepts and prevents the molecule from binding to cells and tissues of irritating the airways. The results are very satisfactory for the moment, with persistent and marked improvements in each of 15 volunteers. To this date November 2005 three of these patients used any steroids from 12 weeks of weekly injections just over twelve months ago.

Other genes are correlated with asthma. A mutation in the gene encoding the protein YKL-40 (a chitinase) and significantly increases the risk of developing asthma15.

Assessing the severity of asthma

An acute asthma attack is characterized by an acute exacerbation of dyspnea , cough and wheezing, and accompanied by a decrease (transient) of lung function. The assessment of the severity of an asthma attack can be done by assessing lung function (peak expiratory flow or PEF, forced expiratory volume per second, or FEV. The clinical evaluation of the severity of the crisis is even more important that the evaluation of lung function, among other reasons because the results of pulmonary function measurements during an acute asthma attack are not always reliable. Depending on the severity of the crisis, it should whether the patient can be treated as first-line service (in-patient in the absence of improvement) or should be hospitalized immediately.

The criteria on basis of which a severe asthma attack should be suspected and immediate hospitalization are considered.

Dyspnea at rest does not allow to impose a sentence in one go.

Respiratory rate> 25/minute in adults> 30/minute in children over 5 years> 50/minute in children 2 to 5 years. (Note: in cases of asthma to be life-threatening, respiratory failure may occur with reduced frequency breathing!)

-       Use of accessory breathing muscles.

-       PEF <50% of predictive value or personal best.

-       Oxygen saturation <92%.

The following warning signs indicate a depletion and the need for immediate admission to an emergency department.

-       Onset of sedation or confusion.

-       Decrease in pulse rate.

-       Decreased respiratory rate.

-       Decrease or absence of inspiratory breath sounds.

-       Cyanosis

-       Disappearance of wheezing.

In following patients who have a high risk of death related to asthma, attention is required and a more rapid hospitalization is required.

-       Patients with a history of near fatal asthma.

-       Patients who were hospitalized in the previous year for asthma.

-       Patients who take corticosteroids by mouth or who have recently arrested.

-       Patients who frequently use beta-2-agonists short-acting inhalers.

-       Patients who do not follow their proper anti-asthmatic chronic.

-       Patients with a history of psychiatric or psychosocial problems (including the use of sedatives).

Psychological Effect

Contrary to popular belief the disease is triggered by somatic or psychological causes. Nevertheless, the effect of stress and panic that usually accompanies an asthma attack worsens respiratory distress felt by the patient including the hyperventilation syndrome.

Calming an asthmatic crisis can improve his breathing, but only a specific medical care (primarily bronchial dilator immediate action) is likely to pass the crisis.

Asthma and Flu

Most people with asthma, like other vulnerable people, may suffer serious complications and exacerbated in cases of influenza.

The vaccine against seasonal flu are recommended (from 6 months, paid 100% for asthmatics) in France by the Higher Council of Public Health of France, and by equivalent bodies in most other industrialized countries ( EU , U.S. ). Vaccination reduces the risk in patients with asthma hospitalization and increased need for medication.

But the three million French victim of asthma (especially children and adolescents), only 32% have been vaccinated in the winter 2006 – 2007 and less than a quarter of under 65 were vaccinated (and only 14% of those under 15 years), against 77% among those 65 and older. The allergic to egg (rare and detectable by skin testing) is the only cons-indicated if the patient is free of infection scalable, fever and / or unstable asthma. Asthmatics vaccinated have no significant side effects or individual within fifteen days (no change in respiratory rate, or increased need for bronchodilators, or increased medical consultations or consumption of steroids).