Australia has one of the highest asthma rates in the world. One in five Australian
children and up to one in 10 adults suffer to some degree from this disease. But
the good news is that asthma is easily treatable.
Asthma is the only chronic condition that is increasing in the Western world and
no one really knows why, although there has been speculation about the role factors
such as pollution and house dust mites may play.
Tragically, though, about 454 people die of asthma in Australia each year - and
at least half of these deaths are preventable. They are young, otherwise healthy
people who get caught out because they are not taking the right medication.
But it's not all bad news. Asthma is easy to treat.
In this Special Report, we explain what asthma is and how it can be managed so those
with the condition can lead full and healthy lives.
People with asthma have over-sensitive airways that respond to irritants in the
following three ways:
- the smooth muscles which surround the airways contract, causing a narrowing of the
air passages
- the mucous membrane which lines the inside of the airways becomes inflamed, further
narrowing the air passages
- this causes increased production of mucus, which clogs the narrowed air passages.
When this happens, a person finds breathing difficult, giving rise to the classic
symptoms of an asthma attack - wheeze, cough, tight chest and shortness of breath.
According to Dr Peter Van Asperen, who heads the Department of Respiratory Medicine
at Sydney's New Children's Hospital at Westmead, the hyper-sensitivity of asthmatic
airways is the result of underlying inflammation which predisposes them to contract
when irritated. It's not known why some people's airways are abnormally sensitive.
However, there appears to be a genetic component as asthma tends to run in families.
Some researchers believe genetic factors may eventually provide an asthma cure.
Most asthmatics are also allergic individuals - their bodies react badly to the
presence of various allergens. Thus, you'll often find that asthmatics or their
close relatives also have eczema, hay fever, or other allergic conditions.
Hormones seem to play a role in asthma, too. In childhood, more boys suffer from
asthma than girls, but the ratios even out during adolescence, and they are reversed
in adulthood when more women than men have the condition. Women's asthma also gets
worse pre-menstrually.
Cigarette smoke is well known as a trigger of asthma attacks in people who already
have the condition. But it can also cause the disease's onset, especially in children
exposed to parental smoking, says Dr David Allen, a respiratory physician in Sydney's
St Leonards. A major cause of adult-onset asthma is exposure to chemicals in the
workplace. The two biggest culprits are a chemical used in the plastics industry,
toluene diisocyanate, and wood dust, especially western red cedar dust. However,
there are more than 200 chemicals that have been implicated in the onset of asthma.
These chemicals can also trigger attacks in people who already have the disease.
The onset of asthma can occur at any age, so it's important to recognise the symptoms
and seek treatment.
Most asthmatics have an audible wheeze that can be accompanied by a persistent,
dry cough and tightness in the chest or shortness of breath. In children, sometimes
the only indicator of asthma is a night cough.
A general practitioner (GP) will find it relatively easy to diagnose asthma in most
cases. If the symptoms improve after the patient is given reliever medication such
as salbutamol (common brands: Ventolin, Respolin), which opens the narrowed air
passages, the problem is almost certainly asthma.
At the initial visit the patient may be asked to blow into a device called a spirometer
to check the maximum volume and flow rate of air he or she can exhale. The patient
may also be asked to blow into a peak flow meter, which measures the force with
which he or she is able to exhale.
In a few cases, the diagnosis may be unclear and the GP may refer the patient to
a lung function laboratory for further tests. These may include skin tests to check
for sensitivity to allergens.
Diagnosis can be more difficult in young children. Dr Van Asperen says that although
wheezing is common in infancy, less than half of these children will have asthma.
The doctor's observations and a history of the child's symptoms from parents can
provide some clues.
Once a diagnosis of asthma has been established, the GP will need to assess its
severity and what the triggers may be. Initially, the patient is likely to be given
medication to settle the symptoms down and the doctor will design a management plan
to keep the asthma under control.
Symptoms vary from individual to individual in duration and severity. Some people
are symptom-free apart from occasional mild wheeze; others, if untreated, wheeze
every day and may face a life-threatening attack.
According to Dr Van Asperen, asthma is classified as mild, moderate or severe according
to the following criteria:
Mild: where an individual has infrequent episodes of asthma - that
is, at the most, one bout of wheezing (requiring regular reliever medication) every
four-to-six weeks - and is symptom-free between episodes.
Moderate: where an individual has episodes occurring more frequently
than every 4-6 weeks, but is symptom-free between episodes.
Severe: persistent asthmatics who have symptoms most days as well
as acute flare-ups from time to time.
The aim of treatment is to minimise symptoms and maintain lung function at its best.
Doctors usually give their patients a tailor-made asthma management plan. It will
detail what medications to take on a daily basis, what to take to relieve symptoms
when they arise, and what to do if their asthma deteriorates.
Some doctors suggest patients monitor their lung function twice daily with a peak
flow meter. People soon get to know what their optimum score is and if it drops
they can increase their medication.
However, Dr Van Asperen says peak flow results are not always reliable indicators
of worsening asthma in children. "Kids can have very variable peak flows just related
to the fact that they don't feel like blowing today," he says. For most children,
he prefers to base asthma management on observation of symptoms.
Medications
The medications used to treat asthma can be divided into two groups - the relievers
and the preventers. They are mostly inhaled, and so deliver the medication straight
to the lungs. There are a variety of devices for delivering inhaled medication.
- Aerosol puffer - both relievers and preventers are available in this form, which
delivers a measured dose of medicated spray.
- Spacer - a cone-shaped holding chamber. It allows medication to be released from
an aerosol puffer into the chamber before the patient breathes in, making the puffer
easier to use and increasing the efficiency of medication delivery. Some spacers
come with face masks for infants.
- Dry powder inhaler - there are a number of these that deliver both reliever and
preventer medication in powder form. Each pharmaceutical company makes its own dry
powder inhaler to deliver its brands of medication - thus, the Rotahaler delivers
Ventolin and Becotide, the Turbuhaler delivers Respolin and Pulmicort, and so on.
- Nebuliser - this is a pump that delivers a mist of medication to the patient via
a face mask. It used to be recommended for delivery of medication during acute asthma
episodes and for children too young to use an aerosol puffer, but delivery via spacer
is now preferred.
Relievers
The relievers, as the name suggests, are taken to relieve the symptoms of asthma.
They are bronchodilators, which means they open up the airways by relaxing the smooth
muscles which surround the airways (and which contract during an asthma attack).
The most common bronchodilators are the beta2 agonists, salbutamol and terbutaline
sulphate. Commonly used brands of salbutamol are Ventolin and Respolin; less common
ones are Asmol and Respax. Terbutaline is marketed as Bricanyl.
As well as relieving symptoms, the beta2 agonists can also prevent their onset if
taken before exercise or in the presence of a known trigger.
Another bronchodilator which is sometimes given in conjunction with a beta2 agonist
is ipratropium bromide (brand name, Atrovent).
Other long-acting bronchodilators occasionally prescribed for severe asthma include
salmeterol (Serevent) and theophylline (Nuelin, Theo-Dur). Theophylline is taken
orally as tablets, syrup or "sprinkles".
Mild asthmatics may only need reliever medication to treat the occasional episode
of wheeze. But people who need to use their bronchodilators three or more times
a week should be on preventative medication. In fact, continual use of beta2 agonists
is discouraged because their overuse increases airway sensitivity, worsening the
underlying asthma. Preventative therapy minimises wheezy episodes and thus the need
for bronchodilator medication.
Preventers
The preventers are inhaled twice daily every day, whether or not the patient has
symptoms. As the name suggests, their regular use helps to reduce the frequency
and severity of a person's asthma attacks. They allow many people to remain symptom
free. The preventers work by reducing the underlying inflammation of the lining
of the air passages, thereby making them less sensitive. But preventer medication
will not open the airways in an asthma attack.
There are two types of inhaled preventer - the non-steroids and the steroids. Dr
Van Asperen says the non-steroids - sodium cromoglycate (Intal and Intal Forte)
and nedocromil sodium (Tilade) - are the first choice for preventative treatment
in children. Children who are well between asthma episodes will usually respond
to Intal or Tilade, although children with daily symptoms generally need an inhaled
steroid.
Intal and Tilade will also help prevent exercise-induced asthma if taken before
sport. Dr Allen says the non-steroids don't have much of a role in treating adult
asthma. "In the adult population the most effective treatment for asthma is inhaled
steroids," he says. The two most common inhaled steroids are beclomethasone (Becotide,
Becloforte, Aldecin) and budesonide (Pulmicort). They come in inhalers which deliver
different sized doses per "puff". Becotide is available in two different puff sizes
- 50 mcg and 100mcg; Becloforte delivers 250mcg per puff; and Pulmicort is available
in doses of 100mcg, 200mcg and 400mcg per puff.
Dr Allen explains: "The usual sort of doses we would give for moderate to severe
asthma would be about 800mcg morning and evening - that would be two puffs of Pulmicort
in the morning and two puffs in the evening. We would certainly go higher if they're
not controlled with that sort of dose."
Dr Van Asperen says once you've got a person's asthma under control with inhaled
steroids, you gradually wind the dose back to the minimum that will maintain control.
Side-effects of inhaled steroids
The most common side-effects of inhaled steroids are relatively trivial - oral thrush
and a husky voice, both of which can be overcome by using a spacer and rinsing the
mouth out afterwards.
However, doctors are cautious about prescribing inhaled steroids for children because
of data that suggests they stunt growth. But there seems to be a "catch-up" effect
once children are taken off the medication and, as Dr Van Asperen points out, untreated
asthma will itself stunt growth.
Dr Allen says adults can safely take up to 1600mcg of inhaled steroids a day. Long-term
doses above that level may cause softening of the bones or easy bruising. It's worth
remembering that the side-effects of poorly controlled asthma can be far worse than
those of the medication.
Fluticasone (Flixotide) is a new inhaled steroid that is more potent than either
beclomethasone or budesonide but has fewer side effects. As yet, it is only available
for people with very severe asthma who have to take oral steroids.
Rescue medication
If a person is suffering an acute asthma attack that is not responding to reliever
medication, they may be given a short course (3-10 days) of oral steroid tablets
(Prednisone and Prednisolone). These are powerful agents that reduce swelling in
the airways.
A short burst of oral steroids will have no harmful long-term side effects. However,
a few people have severe asthma that can only be controlled by a daily low dose
of oral steroids. Long-term, they may notice side effects including puffiness, increased
appetite, mood swings, raised blood pressure, thinning of bones, easy bruising,
slowed growth, glaucoma and cataracts.
The inhaled steroid, Flixotide, can be prescribed as an alternative to regular oral
steroids.
The sources of the information in this article are:
Dr Peter Van Asperen
Dr David Allen
Asthma Management Handbook 1996, National Asthma Campaign
Asthma Foundation of NSW literature.
For further information on asthma phone Free Call 1800 645 130
