ASTHMA - a patient's guide
Dr Adrian Harrison - Chest Specialist, Mercy Hospital

What is asthma?

Asthma is an inflammatory condition of the breathing tubes (or bronchi). The inflammation causes airway irritability and results in airway narrowing (called bronchospasm).

Now, to explain that in a little more detail, let's go back a few steps.

How the lungs work

Our breathing "equipment" is made up of two parts: a set of breathing tubes - similar to the trunk and branches of a tree, except that our breathing tubes, of course, are hollow. At the end of the finest branches of a tree there are leaves. In our bodies, instead of leaves, our lungs are made up of a sponge tissue.

Inhaled air travels down the breathing tubes, out to the finest branches, which are in close communication with blood vessels containing blood. The blood takes the oxygen from the air and carbon dioxide travels in the other direction, from the blood stream back into the airways, where it is breathed out.

The process of gas exchange occurs in the sponge tissue of the lung. The job of the breathing tubes is to get the air in and the carbon dioxide out.

What is different about the lungs in asthma?

In asthma, the sponge tissue works well. The problem lies in the breathing tubes.

The breathing tubes (bronchi) have an inner lining, which is similar to the lining of your mouth. In the middle of the airway wall is a layer of muscle. In asthma, this muscle layer is very irritable or "twitchy" so that a wide variety of trigger factors cause it to tighten. This causes narrowing of the breathing tubes, making it harder to breathe, and also causing chest tightness, wheezing and coughing.

Why is the muscle layer in the breathing tubes so irritable? By far the main reason for this is inflammation. An example of inflammation elsewhere in the body is sunburn. Inflamed tissues are red and swollen. In asthma the lining of the breathing tubes are inflamed.

a) Inflamed tissue contains a large number of white blood cells and these are like tiny chemical factories. The substances they release have a number of harmful effects. They cause blood vessels to become leaky so that fluid seeps out into the tissues - the tissues then become swollen.

b) Other chemicals or substances from the white blood cells attack the inner lining layer of the breathing tubes, causing it to become so damaged that, under the microscope, it looks as though the lining layer has been attacked with sandpaper. Because of this damage, infections and irritating substances we breathe in can affect the breathing tubes more easily and cause problems.

c) Some chemicals released by the white blood cells act like a signal, calling in more white blood cells into the area. Because of this, the inflammation in asthma "has a life of its own" - there is an inbuilt mechanism by which the process keeps itself going on and on.

d) We will talk about asthma medicines later, but one of the most important actions of inhaled steroids is to calm down the white blood cells, reducing the release of chemicals from them, and thus allowing the asthma process to settle down.

A third part of the asthma process is the production of sticky mucus from the inner lining layer of the breathing tubes. Asthma mucus tends to be a pale lemon-yellow colour.

In summary, the key to things to remember about asthma is that it is essentially an inflammatory condition of the airways resulting in over-sensitive breathing tubes, which then react to things which don't cause problems for normal airways.

What are the symptoms of asthma?

Typical asthma symptoms include a tight feeling across the upper chest, cough, breathlessness and wheezing.

A wheeze is a noise - a high pitched noise which comes from within the chest. Anyone can mimic this wheezing sound by tightening their throat muscles and breathing out forcibly. The wheezing in asthma is similar to this, but comes from within the chest, not the throat.

Asthma symptoms may be brought on by head colds, exercise, exposure to pollens or dust to which the person is allergic, or a whole host of other factors.

Not everyone with asthma has these typical symptoms. For instance, a frequent or persistent cough might be the only obvious feature of underlying asthma.

Conditions which can be confused with asthma

Occasionally, people who are elderly are told they have emphysema when, in fact, there may be at least some asthma present.

Hyperventilation - that is, "overbreathing" caused by an abnormal breathing pattern - can mimic asthma. Sometimes people have a combination of asthma and hyperventilation, both of which cause breathing difficulties and chest tightness.

Vocal cord spasm is another condition which is less common, but can also mimic asthma. Here, change in the quality of the voice is usually present, and the wheezes which are heard are generated from the throat, rather than from breathing tubes in the chest.

What causes asthma?

This is not properly understood. In most cases there is no obvious reason why one person develops asthma.

Asthma can be inherited or have a genetic cause, but this is only a factor in about 50% of people with asthma.

We also know that viral infections which attack the breathing tubes can, at times, set off asthma in someone who has never had asthma before. If this type of asthma is recognised in time (within, say, a couple of months) and fairly intensive treatment is given (usually with inhaled steroid and steroid tablets) good treatment has an excellent chance of producing a cure from this form of asthma.

In the work place there are a few substances recognised as causing asthma in people who have never had it before. Toluene di-isocyanate (TDI) is the best known. TDI is found in 2-pot paints (used by car body paint sprayers), and in a number of glues where two components have to be mixed together to form the glue. Persistent exposure to sawdust from Western red cedar can also cause asthma: here the offending substance is plicatic acid, which is a natural chemical found in this particular wood.

There is an important distinction between "causes" of asthma (two of which we have just discussed), and asthma "triggers", which make existing asthma worse.

Asthma triggers

Asthma triggers are things that make asthma worse. The most common asthma triggers include head colds, cigarette smoke, exercise, fumes, allergic substances (such as pollens, pets and dust), weather factors (weather change, cold or humid weather), and change in emotions (such as stress or excitement). Food factors may be important in some individuals but not others.

It is important to know about asthma triggers and to look out for those triggers that affect you. Regularly using a peak flow meter, with recordings morning and night, can help you track down triggers. If you are suspicious of a particular possible trigger factor, measuring the peak flow before and after exposure can help determine if that factor is important or not.

Though many trigger factors cause asthma soon after exposure, some only affect asthma hours later. Another complication is the fact that it sometimes takes a combination of several triggers to make asthma worse, with the individual triggers themselves not causing problems.

Tracking down asthma triggers is important, but it may be an exercise in frustration. You need to decide for yourself how much effort you want to put into finding things that make your asthma worse. Just remember, though, trigger avoidance is a fundamental aspect of good asthma care.

Asthma attacks

Surprisingly, it is not easy to define what is an asthma attack. What the medical profession regard as an asthma attack is worsening of asthma, with an important degree of respiratory distress, or with an important degree of fall in lung function.

Asthma attacks can be sudden and severe, in which case it is important to take extra medication straight away and to get medical attention. At other times, asthma can be mildly, but persistently worse over a period of days, or even weeks, with gradual deterioration. Thus, asthma attacks can have a sudden onset or a slow onset. Either way, when asthma becomes worrying, or distressing, it is time to get help.

Asthma attacks are important because they can result in death if they are not managed properly. Typically, people who are too busy, or just keep on putting off getting medical attention, are the ones who wind up in trouble. "A stitch in time saves nine" - early treatmentof attacks saves trouble; it saves lives.

Looking after asthma

1. How you feel about asthma is important

Most people with asthma can live normal lives if they look after asthma conscientiously. Up to 10% of people with asthma have problems which cause some interference with their life despite good treatment. But this interference can be minimised with good treatment.

How you feel about your asthma and the treatment is important. Some people feel angry because they have asthma, become frustrated because they can't stop problems occurring, and hate having to take medication. While these feelings are natural and normal, it is a fact that they are a source of unhappiness. More than this, these feelings about asthma can produce a significant amount of stress which, in turn, can make the asthma worse.

Behind all these negative feelings, I suspect that there lies a fear, or probably a number of fears. It may be that these fears become mixed up with a wider pattern of fears about other issues. If this feels familiar to you, it may be worth taking steps to manage stress, fear or anger, for instance, by reading books, attending courses, or considering a counsellor, for instance.

Be determined, calm and responsible in looking after asthma. The problems associated with the condition can be considered to be tests and trials to be overcome. If you are interested in developing yourself into a stronger, more effective person, asthma could be an ideal training ground! Surrendering to anger, annoyance or stress isn't the answer. Good help is available, good medications are available. Success in looking after asthma should be expected - there are plenty of people who can help.

2. Trigger avoidance

In the section on asthma triggers, it was made clear that trigger avoidance is one of the cornerstones of good asthma care. Some of the following may be appropriate for you:

At the first sign of a cold or flu, increase your preventer treatment (usually this will be the inhaled steroid - see below).

Don't smoke - this is the worst thing you can do if you have asthma, even if the asthma seems trivial.

Don't tolerate being a passive smoker - consider making a rule for your home (and work place): "No Smoking Here". If you just can't get away from smokers, try and sit in a smoke-free area or near an open window.

If exercise makes your asthma worse, take your reliever inhaler 10-20 minutes before exercise. Exercise is one trigger that needs to be controlled, rather than avoided, if at all possible. Warm up exercises may also reduce exercise-induced asthma.

House dust allergy is caused by tiny mites which eat the skin we shed. House dust mites are unavoidable in modern life, but exposure to house dust must be minimised. Here are some tips for avoiding them and other asthma triggers:

Put bedding items in direct sunlight every couple of weeks - direct sunlight kills the dust mite.
Wash bedding in warm water regularly.

Either avoid using sheepskins and electric blankets, or air them frequently in sunlight. Sheepskin can also be washed.

Vacuum frequently (perhaps twice a week) using a vacuum which doesn't expel dust into the air through its exhaust system.

Don't use a feather duster - use a damp cloth to dust other surfaces.

Don't allow pets into the bedroom and, if possible, keep them outside. Pets carry dust and dirt; it's not just allergy to their dander that is important.

Take extra medicine during the pollen season if pollens affect you.

Damp houses are associated with worsened asthma - keep your house warm and dry. Clean away mould straight away, checking wardrobes and cupboards.

Foods and drinks can be important trigger factors - metabisulphite and monosodium glutamate (MSG), as well as the colouring agent tartrazine, should be avoided.

Aspirin and the class of pain relievers called NSAIDS affect about 5% of people with asthma, making their asthma worse. If you are sensitive to them, they should be avoided. (If you change doctors, remember to let the new one know).

Principles of good asthma care

Trigger avoidance.

Don't ignore symptoms: when asthma gets worse, extra treatment is required. If it gets much worse, see your doctor.

Preventer treatment should be taken regularly - usually this means twice a day. Preventers reduce airway inflammation, which is the fundamental problem in asthma.

When you stop your preventer treatment inflammation automatically starts getting worse.

See your doctor and obtain an action plan. This will help you recognise an asthma attack and know what to do about it.

Have regular check ups with your doctor. The more troublesome the asthma, the more frequent the check-ups. Even people with very well-controlled asthma should see their family doctor at least twice a year.

Natural therapies for asthma

There are a large number of natural therapies available - for instance homeopathy, acupuncture, chiropractic manipulation, aromatherapy and many more. Only a few have been subjected to scientific testing to prove whether or not they help. The results of the studies which have been done are disappointing: they don't show good effectiveness. However, some of these treatments might well be helpful in mild asthma. They are unlikely to be effective in troublesome asthma, because of the severity of airway inflammation.

People who use these therapies should obviously continue them if they are effective. If you want to try out a new form of therapy, it is important not to stop conventional medications. A better approach would be to start the "natural" therapy and see if you are able to reduce some of the medication. If you have a comfortable relationship with your family doctor, talk to him or her about the balance between "natural" and conventional medication.

It is common for people to not want to be dependent on medications, or to take as little of them as possible. However, most asthma medicines are very safe and can be taken for a lifetime without major problems. The dose of inhaled steroid which is regarded as being completely safe would be 500mcg of beclomethasone or budesonide in a child, and twice this amount per day for an adult. Above these levels, these two medicines can have minimal side effects up to about 1500mcg per day. High doses are occasionally prescribed and can be taken without problems for a few weeks. Discuss with your doctor the balance between the risks and benefits of these high doses.

The overall message about asthma medicines is that usual doses are very safe indeed. These are an excellent option, as they can control asthma without side-effects and allow people to live a normal, happy life.

Asthma medicines

1. Bronchodilators, or relievers

These medicines relax the layer of muscle in the wall of the breathing tubes, allowing the breathing tubes to open up. When they are taken at a time when symptoms are present, they give relief - hence the name.

Short-acting bronchodilators such as Ventolin, Bricanyl and Respolin are known as "short-acting beta agonist bronchodilators". They work for up to 4-6 hours in mild asthma.

Atrovent is another short-acting bronchodilator, unrelated to the beta agonist group. It works by blocking the constricting action of the vagus nerve on bronchial muscle.

Serevent and Foradil are long-acting beta agonist bronchodilators - their action continues for up to 12 hours. Long-acting beta agonist inhalers are taken regularly twice daily. The recommended dose should not be exceeded.

Avoid using high doses of relievers as the usual treatment for long periods. The shorter-acting beta agonist inhalers can be taken when needed, but if you need 8 puffs or more per day on a regular basis, you must get medical attention. Long periods on high doses of the beta agonist inhalers is associated with increased airway irritability and worsening of asthma.

The best way to allow the dose of reliever inhalers to be minimised is to take preventer inhalers regularly.

Shakes, or a rapid heartbeat, are sometimes noticed when first using a beta-agonist reliever inhaler, but these are usually mild. They are not dangerous, and they disappear once the medicine has been used for a few weeks.

Two types of reliever tablets are available:

Beta-agonist tablets - this is a tablet form of Ventolin (salbutamol)

Theophylline tablets or capsules - frequently used brands are Nuelin and Theodur. Nausea and headaches are common side effects, which can be minimised by taking these medicines straight after food. These particular medicines also have anti-inflammatory actions (thus acting as a preventer medicine), although they act mainly as relievers.

2. Preventers, or controllers

This group of medicine acts by reducing airway inflammation, which is the basic problem in asthma. Preventer treatment is fundamental to asthma care.

Preventers work by stopping the white blood cells from releasing the chemicals they would otherwise produce. As the inflammation settles, the asthma gradually calms down and the muscle irritability reduces. However, although people usually feel well within a few weeks of taking regular preventer treatment, it takes between one and two years at least before the inflammation in the airways to settle. Preventers only work when they are taken regularly every day - usually twice a day. You don't feel any better when you take them, but after a few weeks the asthma usually starts settling down. Then less reliever medication is needed.

Preventers, or controllers, fall into three main categories:

a) Corticosteroids: inhaled steroids are best because they give a small dose. Steroid tablets, such as Prednisone, are needed when asthma is more severe. When you use an inhaled steroid, you can reduce the amount of steroid which is absorbed into the body by gargling with water, rinsing the mouth and spitting the water out. This can reduce the amount of steroid which gets into your body by up to 80%. Gargling, rinsing and spitting also reduces the chances of the inhaled steroid affecting your voice or causing thrush.

b) Intal, Vicrom and Tilade: these medicines are all related because they belong to a class of medicine called cromolyn. They are not steroids. They are less effective than steroid treatment but sometimes work well in children. They generally need to be taken three or four times a day, whereas inhaled steroids are usually only taken twice a day.

c) Leukotriene inhibitors: these are a new class of medicines, one example being Singulair. Leukotrienes are a family of substances which, when released from body tissues, cause inflammation. These substances are not important in all asthmatics. Experience is still being gathered to decide which people with asthma actually benefit from leukotriene antagonist tablet treatment.

Treatment of other conditions which can affect asthma

a) Hay fever and sinus problems can make asthma worse. If your asthma isn't well-controlled and you have upper respiratory tract problems, see your family doctor.

b) Indigestion and reflux from a hiatus hernia can also make asthma worse. Treatment for these conditions can be important in minimising problems from asthma.

Getting better control of asthma

If your asthma isn't well controlled, despite the best efforts of yourself, your family and your doctor, consider asking your family doctor to refer you to an asthma specialist.

Asthma devices

1. Peak flow meters

A peak flow measures one aspect of lung function. A peak flow meter is a simple device with a mouthpiece and a measuring system with a pointer. Blowing through the mouthpiece as hard and fast as you can enables the speed of the air which has been blown out to be recorded. To use a peak flow meter correctly (1) take as deep a breath in as possible, (2) then secure the mouthpiece to between your lips, and then (3) blow out as hard and fast as possible, emptying your chest of air in the first second.

In asthma, narrowed breathing tubes slow down the speed of airflow, resulting in a lower reading on the peak flow meter. After taking an inhaled reliever, waiting 10 or 15 minutes and then repeating the peak flow measurement, a higher reading will usually be seen.

Not everyone with asthma needs a peak flow meter. Peak flows can be useful in several circumstances.

To help identify asthma triggers: If you think a particular food or exposure to a pet, for instance, makes your asthma worse, it is possible to test for this. Take a peak flow reading before exposure to the possible trigger, and, following exposure, take a series or readings - perhaps 5 minutes after exposure, when your chest feels tight, and perhaps 4-6 hours after exposure.

To see if a new medication improves the asthma: To do this, record your peak flows morning and evening for about a week. Make a note of when you start the new medication, and keep the recordings going twice daily. In the case of a new preventer, it may take a couple of weeks before your peak flows show improvement.

To identify asthma attacks: Sometimes it is helpful to start recording your peak flow as soon as you are exposed to a trigger factor, which sets off asthma attacks, or as soon as you notice any deterioration in asthma. It is important to know your peak flow readings when you are well - keep a record for at least a week, then, when you get a head cold, for instance, start peak flow readings straight away, recording them morning and night. If the peak flow starts to drop, increase your preventer inhaler as directed by your doctor. Your doctor will be able to devise an action plan to enable you to add additional treatment as the peak flow gets lower, to prevent the development of a full-blown attack.

To show whether the asthma is stable, or not: Normally peak flows only vary 30 - 40 litres per minute if a person has stable asthma. If the peak flows show more than 100 litres/minute variation from highest to lowest values during the course of a week, this indicates the asthma is not stable and your doctor should review your peak flow record and the treatment you are taking. Unstable asthma puts people at risk of asthma attacks.

2. Nebulisers

Nebulisers are used to enable people to get a full dose of medication - in 99% of cases, this will be a reliever medicine.

A nebuliser consists of an electrical air pump which pumps air through plastic connecting tubing which is attached at its other end to a nebuliser bowl, and either a face mask or mouthpiece. A mist of medication spray issues from the face mask or mouthpiece and this is inhaled.

Small children and people with disabilities who are unable to use other asthma devices sometimes need a nebuliser. Nebulisers are generally used in an emergency-type situation, such as a doctor's surgery or Accident and Emergency Department, to give the high dose of medication needed to treat an asthma attack. Sometimes people with very troublesome asthma, despite otherwise good treatment, require a nebuliser.

Before thinking of getting a nebuliser, it is important to have tried non-nebuliser medications on a regular basis. Fewer than 5% of people with asthma require a nebuliser.

3. Other inhaler devices

The original asthma inhalers came in the form of a glass bowl with a hand-held rubber pump which was squeezed, creating a jet of medication aerosol. These days, the devices to deliver inhaled asthma medications are much more scientific and deliver a measured dose of medication. Also, the size of the inhaled particles is designed so that it can travel right down into the lungs, and does not just impact in the throat or upper airway.

a) The technique of using inhaler devices:

With all inhaler devices (except nebulisers) there are 3 key steps to obtain an effective dose. They are:

i) gently and comfortably exhale

ii) then inhale the medication slowly, over 2-3 seconds

iii) then, hold your breath for 10 seconds, if possible.

A very rapid inhalation and a short (or no) breath-hold results in very poor amount of medication staying in the lungs and helping the asthma.

b) Pressure pack inhalers: These are called "metered dose inhalers" (MDI's). They are still useful but have limitations. The main problem is that care is needed to coordinate the timing of (i) firing the inhaler and (ii) breathing in. Dose-delivery from an MDI can be improved by firing the dose into a plastic chamber called a "spacer" and then inhaling from the spacer - as explained in (a).

c) Non-MDI devices. There are several available now and others will come available in the future. They include the Accuhaler, the Autohaler, Diskhaler and the Turbuhaler. Which of these is selected depends largely on you and your doctor, as well as the medication selected as being best for you. Although there are differences in how these devices perform, they are not important for most people.