Asthma

AsthmaIn asthma, the inflammatory reaction causes swelling of the airway mucosa and narrowing of the airways, producing the typical disease symptoms. According to the World Health Organization data, 5% of world population suffers from asthma which appears in all ages, but mainly before the age of 10. Asthma can be divided into allergic asthma and intrinsic asthma. Allergic asthma is caused or exacerbated by known allergens; intrinsic asthma, however, is characterized by the absence of a certain cause.

Why should you have your DNA analysed for predisposition to asthma?

We check your genome in different loci, for your genes can also influence the development of asthma in the presence of environmental air pollution.

How is asthma prevented or treated?

Asthma always comes in attacks, lasting from minutes to several hours. During the attack, dyspnoea, cough and wheezing develop. Asthma medications alleviate the symptoms or even prevent the attacks.
An absolute protection against allergic asthma is impossible because the number of allergens keeps increasing in today's developed world.

More detailed description about asthma

Asthma is very common; according to the WHO data, 5% of the world population suffers from asthma. The disease appears in all ages with the majority of cases discovered before the age of 10. This holds especially true for the so called atopic or childhood asthma. The other type is intrinsic asthma which typically appears in adulthood. Boys are more commonly affected in childhood years, while in adulthood these differences in incidence disappear.

Asthma comes in attacks which can last from a few minutes to several hours. During an attack the patient experiences shortness of breath (dyspnoea), cough and wheezing. Severe symptoms of suffocation can develop if asthma is complicated by a coexistent upper airway infection, if specific allergens are inhaled or if the inhaled air is either very cold or very hot. Between attacks, patients generally remain symptom-free.

An asthma attack can also be triggered by physical activity, and in women the disease often worsens before menstruation. Drugs, especially aspirin, can also exacerbate asthma. Other asthma triggers include polluted environmental air, workplace health issues, infections and emotional stress.

Forms of asthma

Asthma can be subdivided into the allergic and non-allergic (intrinsic) asthma. The latter is characterized by having no known cause. Possible causes could include viruses or antibodies that target the lung tissue. Allergic asthma can typically be caused or exacerbated by specific allergens (i.e. substances that trigger an immune response and usually do not harm a healthy body). A history of atopy is the strongest risk factor for the development of allergic asthma. Atopy or atopic syndrome is an allergic hypersensitivity affecting parts of the body not in direct contact with the allergen. Affected individuals have a hereditary predisposition to various allergic diseases including asthma. In childhood, the prognosis of asthma is excellent; 50% of children who suffer from asthma in childhood are disease-free in adulthood. However, asthma can be very dangerous, for a patient can suffocate to death during a severe attack.

The development of allergic asthma is IgE antibody-mediated. When the patient inhales an allergen, special immune cells called mastocytes begin to secrete many inflammatory mediators, most importantly histamine, under the influence of IgE antibodies. The secretion of inflammatory mediators leads to an inflammatory reaction. Airway mucosa swells up and narrows the airways. If the patient is not treated aggressively, permanent injury of airway mucosa may result.

Diagnosis

On appearance of asthma symptoms, diagnosis is made on the basis of a good patient history and a physical exam. The final diagnosis is made based on the results of the pulmonary function tests (PFTs). Asthma can also be confirmed by exposing the airways to special substances and measuring their response.

Prevention

Asthma prevention is directed mainly at preventing acute attacks that present with cough, dyspnoea, wheezing, a choking sensation and chest tightness.

Asthma patients need to:

  • know the triggers of their asthma attacks, which may be various allergens (pollen, dust mites, cat fur, etc.), viral infections of the upper airways, physical stress, cigarette smoke, emotional stress, cold and/or polluted air as well as certain medications;
  • master the technique of inhalation of the asthma medication;
  • master the technique and regularly measure their peak flow in the lungs using the so called PEF meters. In this way, an imminent attack may be recognized and appropriate action can be taken;
  • have a plan of action detailing how to act in the case of an acute attack, even before medical assistance is sought.

Therapy

Asthma therapy generally includes avoidance of all known triggers as well as the use of one or more medications. Because the disease varies with time, it is important to closely follow the symptoms and control the pulmonary function. Because of the need for adequate treatment adjustment, a good cooperation between the patient and the physician is required.

The aim of the therapy in the first line is the treatment of chronic inflammation of the airways and prevention and control of the acute exacerbations.

Two groups of medications are used to that effect:

Short-acting drugs, such as the bronchodilators, are used for immediate treatment of attacks. These medications are symptomatic medications; they are used on a per need basis, i.e. when the patient first starts to feel dyspnoea. These medications act to dilate the airways by relaxing the airway muscles. The group includes the short-acting beta-2-agonists such as salbutamol. They take their effect in a few minutes and last for 4-6 hours.
Medications for long-term control, used on a daily basis, include the anti-inflammatory drugs such as the inhalation corticosteroids that represent the initial drug of choice. They may also be used in combination with the long-acting beta-2-agonists and antileukotriens, etc. in the case that the desired control has not been achieved.

In patients with allergic asthma for whom the culprit for the attacks is the known hypersensitivity to a specific allergen, the following may be of use:

Avoidance of the known allergens is the most important step that a patient can take towards prevention of allergic reactions and decrease of the number of asthma attacks. In immunotherapy, increased amounts of the responsible allergen are injected subcutaneously with the aim of conditioning the immune system and reducing its sensitivity to this allergen. The goal is to ameliorate the asthma symptoms, as well as to reduce the need for medications and the danger of future serious asthma attacks. Initially, injections are administered once or many times per week for about 30 weeks. With time, the doses are administered in increasingly long intervals or once per month. The therapy is carried out for 3 to 5 years, in some cases even longer.

Medications such as systemic anti-histamines; they can be used regularly in the case of dust mite and cat fur hypersensitivity, or only during the periods of greatest exposure, such as in the spring, in the case of pollen hypersensitivity.

In addition, important measures include professional counselling (because choosing the wrong profession may expose the patient to the known allergic triggers) as well as vaccination against influenza and pneumococcus.