Читать книгу Asthma-Free Naturally: Everything you need to know about taking control of your asthma - Patrick McKeown - Страница 9

So what is asthma and what are the symptoms? The condition consists of inflammation, tightening and swelling of the airways in the respiratory system, resulting in obstruction of the flow of air to and from the lungs. The symptoms of asthma include breathlessness, wheezing, coughing and chest tightness. Sufferers may also have a blocked nose, frequent colds and hay fever, or rhinitis. The symptoms and their severity are peculiar to the individual, and they vary from season to season and according to the individual’s susceptibility to a wide range of triggers.

An ‘asthma attack’ is the term used to describe an episode of breathing difficulty. In some cases, this may follow exposure to a specific trigger, such as dust, pollen, or certain

Airways narrowing

foods. In other cases there appears to be no particular trigger. Some people have a cough and no wheeze, while others may have a wheeze and very little coughing, but each case is accompanied by some level of breathing difficulty. Symptoms may occur periodically, on a day-to-day or season-to-season basis, or they may be more or less continuous.

A ‘trigger’ is something that makes asthma worse. The most common triggers include (in alphabetical order): allergies; cigarette smoking (and cigarette smoke for nonsmokers); colds and flu; cold air; dust mites; exercise under certain circumstances; moulds; noxious fumes; pollens; stress, and weather types such as fog and damp. In some instances an asthma attack may be triggered by a combination of catalysts. Anxiety can be caused by the variations on the asthma theme, particularly where a child is involved. Sometimes, there may be confusion between doctor and patient when a diagnosis is being made.

There is also a wide variety in the symptoms of asthma. The following is a list of those most commonly experienced by sufferers.

♦ Wheeze

This is a high pitched whistling sound produced when air is forced through narrowed airways. If you blow through a Biro pen when the ink refill is removed, the sound is similar.

♦ Breathlessness

This is the feeling of not being able to take in enough air. There is a need to breathe out while, at the same time, a compulsion to breathe in. If this symptom develops to an extreme level it can be frightening for the sufferer and very distressing for those close to him or her.

♦ Coughing

This may be either a repetitive dry cough or a cough with phlegm, often occurring during the night or early morning. Repetitive coughing can put a strain on the heart and drives sputum deeper into the lungs. Patients with this symptom may feel like they are on a conveyor belt: the more they cough, the more they feel the need to cough again.

♦ Chest tightness

Trapped air in the lungs generates a feeling that the chest is over inflated. This is often described as someone squeezing or sitting on one’s chest.

♦ Frequent yawning

When asthma symptoms are at their worst, sleep is interrupted by difficult periods of breathing which contributes to tiredness.

Non-asthmatics can, of course, observe these symptoms, but they will not appreciate the feelings of tension, panic, uncertainty and helplessness which accompany them, particularly when the asthmatic struggles to breathe. If you are not an asthmatic, imagine trying to breathe while a pillow is being pressed firmly over your face. That feeling you imagine is the feeling someone with asthma has during an attack. In your case, the imaginary pillow can be easily removed to allow you to breathe effortlessly; for an asthmatic, the remedy is not so simple.

Given the variety of symptoms and their severity, diagnosing a condition that has no commonly accepted definition is not an exact science. Many asthma symptoms are also the symptoms of other conditions, such as chronic bronchitis or bronchiectasis, for example. Diagnosis has to take into account the chronic nature of asthma and the constriction of the airways due to inflammation by various cells and chemicals. Generally, diagnosis of asthma is based on the following factors.

♦ History of the patient

This includes establishing if the patient has experienced asthma symptoms while at rest, during exercise or after exposure to a known trigger.

♦ Lung function tests

The peak flow meter measures the maximum speed at which the patient can exhale air in one second. A person with asthma usually produces a lower reading, and, generally speaking, a more inconsistent range of results than a person who doesn’t suffer from the condition. Spirometry measures both the speed and volume of air which is exhaled with each breath, thereby providing additional airway obstruction information.

♦ Effect of reliever or steroidal medication

In part, diagnosis of asthma is based on the effects of medication, and whether or not it leads to a temporary reversal of symptoms. Other conditions which demonstrate common asthma-type symptoms, such as emphysema, include irreversible airway obstruction.

♦ Provocation test

The patient inhales a broncho-constricting agent, such as histamine or methacholine. The airways of people with asthma are far more responsive to inhalation of these substances; agents like these will provoke more extensive narrowing of air passages in people with asthma.

♦ Skin tests to determine allergies

A number of common allergens are selected, such as dust mites, pollen or animal dander. One at a time, the allergens are placed on the forearm, and the skin is then gently pierced to allow the substances to penetrate. After fifteen minutes, the skin surrounding this spot may develop a small rash. While this test is not always conclusive, the presence of a rash and the size of the weal indicate an allergy to a specific substance.

♦ Chest x-ray

X-ray is used to rule out other respiratory diseases in a person who has the symptoms of severe chronic asthma. X-ray charts show irreversible damage to the airways, and this aids the diagnoses of other respiratory disorders.