ASTHMA

Asthma is a chronic disease in which sufferers have repeated attacks of difficulty in breathing and coughing. It is due to reversible contraction and constriction of smaller airways in the lungs known as bronchioles.

The smallest tubes (bronchioles) are only millimetres wide and they are made up of ring-shaped muscles that are capable of contracting or relaxing. Anything that makes them contract will narrow the passages such as inflammation of the inner lining of the tubes, which makes it more difficult for the air to pass through and also gives rise to the characteristic wheezy noise.

Asthmatics tend to be sensitive to various types of irritants in the atmosphere that can trigger this contraction response from the bronchial muscles.

People of all ages get asthma but 50 per cent of sufferers are children, mostly boys, under 10. Among adults, women are more likely to develop asthma than men.

Trigger factors for asthma

  • Emotion, in most cases intense emotion
  • Exercise
  • Infection due to corona virus or rhino virus
  • Allergens such as house dust, feathers, animal hair, pollutants etc
  • Drugs such as aspirin, beta blockers, anti-inflammatories {NSAIDS}
  • Cold air


Patients usually have a genetic predisposition to the condition and might also suffer from other allergic conditions such as hay fever, eczema etc.

Symptoms

  • Intermittent wheezing
  • Difficulty breathing or otherwise known as dyspnoea
  • Chest tightness
  • Cough, could be at night
  • Disturbed sleep


Signs of asthma getting worse

  • Inhaled medicines appear less effective than usual.
  • Symptoms of increasing wheeze and cough on exertion
  • Night-time wakening with wheezes or coughs.
  • Fall in the peak flow meter reading (a peak flow meter is a simple device that measures the maximum speed at which a person can breathe out).


When it appears that your asthma is becoming less well controlled, you should consult your doctor for advice on what to do.

Signs of severe asthma

  • Bluish skin colour and gasping breath.
  • Exhaustion so severe that speech is difficult or impossible.
  • Confusion and restlessness.
  • Immediate medical attention is needed in such cases.


Things to bear in mind

  • Avoid the substances you are allergic to, if possible. It could be house dust mite, grass pollen, pollutants, cigarette smoke, feathers, animal hair etc. Sometimes an attack can be induced by exercise.
  • If you are on inhalers it is important you use them as prescribed by your general practitioner, even if you feel well.
  • Always discuss your treatment with your general practitioner or practice nurse. You should know what to do if, for example, you get a bit worse during a cold. This will usually involve a temporary increase in the dosage of your treatment such as your inhalers.
  • Be familiar with the use of a peak flow meter, which can help you judge your asthma during spells when it is worse.
  • Make sure you use your inhaler device correctly. If you are unsure your practice nurse, doctor or pharmacist will be able to help and advise you.
  • If you get a serious attack, contact your doctor or the emergency services immediately


Diagnosis The diagnosis is made on the basis of the patient's history of symptoms and on simple tests of the lungs' function.

Sometimes an allergic screening like a skin test might be required to look for hypersensitivity and find out which allergens might be responsible.

Long term outlook

  • Asthma often improves in children as they reach their teens, but it could return in the second, third or fourth decades.
  • Overall asthma tends to improve with age.
  • It is vital to stop smoking to avoid developing long-term lung damage (chronic bronchitis, 'smoker's lung'), which will reduce the lung function drastically.
  • Severe attacks of asthma can be fatal but only if they are treated inadequately or not soon enough.


Management of asthma

Preventive measures such as cessation of smoking, avoidance of allergens are crucial.

Avoid drugs that can induce asthma such as beta blockers, aspirin and certain anti-inflammatories.

Medicines for asthma are generally thought of in two main groups.
  • Bronchodilators as the name implies dilates the bronchi or the airways. These are quick-acting medicines. This opens the airways and makes it easier to breathe. They basically relieve the symptoms.
  • Anti-inflammatories act over a longer time and work by reducing the inflammation within the airways. They should be used regularly for maximum benefit. They mainly prevent attacks of asthma. When the dosage and type of anti-inflammatories is correct, there will be little need for bronchodilators.


Bronchodilators
There are three groups of these.
1. Beta-2 adrenoreceptor agonists
2. Beta-2 agonists act on molecule-sized receptors on the muscle of the bronchioles. They relax the muscles of the airways and act within minutes. Examples of those which act for a short time (three or four hours following a single dose) are salbutamol and terbutaline. These start to work very quickly after inhalation and are used when required to relieve shortness of breath. They can also be used to open the airways before exercise.

Longer-acting beta-2 agonists include salmeterol and formoterol. Their action lasts over 12 hours, making them suitable for twice-daily dosage to keep the airways open throughout the day.

Formoterol works rapidly to open the airways like the short-acting beta-2 agonists. A combination inhaler which contains formoterol together with the corticosteroid budesonide, is licensed to be used regularly as a preventer and when needed as a reliever to relieve shortness of breath.

Beta-2 agonists are inhaled from a variety of delivery devices, the most familiar being the pressurised metered-dose inhaler (MDI). Other devices include breath-actuated inhalers such as autohalers and dry powder inhalers such as turbohalers.

Anticholinergics

One of the ways in which the size of the airways is naturally controlled is through nerves that connect to the muscles. The nerve impulses cause the muscles to contract, thus narrowing the airway. Anticholinergics medicines block this effect, allowing the airways to open. The size of this effect is fairly small, so it is most noticeable if the airways have already been narrowed by other conditions, such as chronic bronchitis. An example of an anticholinergic is ipratropium bromide. It has a maximum effect 30 to 60 minutes after inhalation, which lasts for three to six hours.

Theophyllines

Theophylline and Aminophylline which is converted to theophylline in the body are given by mouth. It acts by inhibiting an enzyme phosphodiesterase therefore relaxing the airway muscles. Aminophylline is given intravenously in severe cases of asthma, but the drug levels in the blood needs to be closely monitored as they can induce arrhythmias or irregular heartbeats.

All three types of reliever can be combined if necessary.

Bronchodilators

There are three main groups of these.
Corticosteroids
Corticosteroids or 'steroids' such as beclomethasone, budesonide and fluticasone have made an enormous difference to the management of asthma. They work to reduce the amount of inflammation within the airways, reducing their tendency to contract and have allowed many patients with previously troublesome asthma to lead almost symptom-free lives. They are usually given as inhaled treatment, although sometimes oral steroid tablets such as prednisolone may be required for severe attacks.
Although steroids are powerful medicines with many potential side effects, their safety in asthma has been well established.

Cromones There are two medicines in the cromone group: sodium cromoglycate and nedocromil sodium. They also act to reduce inflammation of the airways. They tend to be best for mild asthma and are more effective in children than adults. The medicines are given by inhalation and are usually very well tolerated.

Leukotriene receptor antagonists

Leukotrienes are released from the lungs in people with asthma, causing inflammation and increased mucus production in the airways. They also cause the muscles lining the airways to contract, which narrows the airways. All of this makes it difficult for air to get in and out of the lungs.

Leukotriene receptor antagonists block leukotriene receptors in the lungs and, as a result, block the action of the leukotrienes. This prevents the excess mucus production, inflammation and narrowing of the airways and so prevents asthma attacks. It’s also useful for preventing asthma triggered by exercise.

By blocking this effect with these antagonist medicines the constriction is reversed. There are two leukotriene receptor antagonists currently available: montelukast and zafirlukast, both of which are taken as tablets.

Combination inhalers Combination inhalers have been the mainstay of asthma treatment for a number of years.
In the 1990s longer-acting combinations of bronchodilators and/or corticosteroids in one apparatus were developed. There are currently a number of these regularly used in the UK, such as Seretide (salmeterol, fluticasone), Symbicort (budesonide, formoterol) and Combivent UDVs (salbutamol, ipratropium).

Many patients feel their asthma is much better controlled on these combination inhalers and compliance is much better as they only need to use one inhaler rather than two.

Please consult the online doctor for bespoke, evidence based and confidential medical advice.