ASTHMA

Asthma is a common chronic disease affecting approximately 5% of adults and 15% of children (see p. 94). It is a disease characterised by increased responsiveness of the airways to a variety of stimuli. The clinical picture is one of wheezing, coughing or shortness of breath, often worse at night. The following is based on the 2005 update of the British Thoracic Society Guidelines for Asthma first published in Thorax in 2003.

CHRONIC ASTHMA

Diagnosis

History.

The suspicion of asthma should be raised if there is a history of chronic recurrent cough or wheeze.

Tip

A diagnosis can be made after more than two episodes of wheeze or cough which respond symptomatically to adequate bronchodilator or prophylactic therapy.

Ask about:

• the duration of symptoms and current treatment

• present symptoms and their effect on lifestyle, e.g. sleep disturbance, time off work or school, effort intolerance

• family history

• atopy

• active and passive smoking

• occupation

• drugs.

Examination/peak flow data

• Examine the chest.

• Measure height (and weight for children).

• Measure the PEFR and calculate the predicted PEFR.

• Prescribe a peak flow meter (if it seems appropriate and the asthma is chronic), available on FP10, and teach the use of the peak flow meter and peak flow charts.

In any patient over 12 years old, reversible airways obstruction should ideally be demonstrated via peak flow measurements by:

1. a 15% improvement in PEFR 5 minutes after an inhaled bronchodilator, or

2. a 15% variability in PEFR on a diary kept over a 2-week period when there are no exacerbating factors such as an infection, or

3. a 15% improvement in PEFR during a trial of high-dose oral steroids.

Management

Advice

• Discuss the disease and the principles of treatment (especially the difference between relief bronchodilators and prophylactic anti-inflammatory treatment).

• Teach an appropriate inhaler technique.

• Discuss a self-management plan, where appropriate.

• Emphasise the need for regular review by the GP or nurse.

Management principles

• Avoid provoking factors, e.g.:

– smoking (active or passive)

– house dust mite (cover mattresses and pillows with plastic covers and minimise carpets, soft furnishings and soft toys, especially in the bedroom)

– pets

– drugs: avoid aspirin, NSAIDs and beta-blockers (including eye drops).

• Discuss stress as a common exacerbating factor.

• Encourage self-management (see p. 173).

Tip

Advocate the use of prophylactic treatment even with mild asthma (in patients who need a bronchodilator three times per week or more). The need for bronchodilators is therefore kept to a minimum.

• Select an appropriate inhaler device. (Aerosol inhalers are always more effective if used with a spacer device.) The use of dry powder, e.g. disks, capsules or breath-actuated inhalers may be useful for those who find simple aerosol inhalers difficult to use because of poor coordination.

• Assess inhaler technique regularly, especially if control is poor.

• Treatment should be step-wise (see below), and should be started on the step most appropriate to the severity of the asthma.

• Treatment should be stepped up and down as necessary, depending on the symptoms, the extent of bronchodilator use and the PEFR.

• The need for relieving bronchodilators should be kept to a minimum.

• Use short-term oral corticosteroids for severe asthmatic episodes to bring asthma under control.

Drug therapy (for older children and adults)

Summary of stepwise management of asthma in adults, 2004. Reproduced with permission from the British Thoracic Society/Scottish Intercollegiate Guidelines Network Executive Committee.

Step one.

Occasional symptoms: intermittent use of a short-acting bronchodilator to relieve symptoms, e.g. salbutamol 200 μg (two puffs of aerosol) prn.

Step two.

More frequent symptoms, e.g. if bronchodilator treatment is required three times per week or more: regular use of inhaled anti-inflammatory agents, e.g. beclometasone 100–400 μg (1–4 puffs of beclometasone 100 aerosol inhalation) bd, plus short-acting bronchodilators as required.

Step three.

Worsening symptoms or increasing requirement for bronchodilators: consider inhaled long-acting beta-agonists, e.g. salmeterol 50–100 μg (2–4 puffs of aerosol) bd.

Step four.

Worsening symptoms or an increasing requirement for bronchodilators: as above, plus a sequential therapeutic trial of one or more of the following:

• Regular use of high-dose inhaled steroids, e.g. beclometasone 500–1000 μg bd plus short-acting bronchodilators as required. A spacer should always be used.

• Sustained-release theophylline, e.g. Slo-Phyllin 250–500 mg bd.

• Inhaled sodium cromoglycate or nedocromil, e.g. Intal aerosol inhalation 2 puffs qds.

• Long-acting beta-agonist tablets, e.g. Volmax 8 mg bd.

• High-dose inhaled bronchodilators, e.g. nebulised salbutamol. (Long-term use should be supervised by a chest consultant.)

• Leukotriene receptor antagonist, e.g. montelukast 10 mg tablet od.

Step five.

If control is lost at any stage consider a short course of oral steroids, e.g. prednisolone 30–40 mg mane for 5 days, or until the peak flow has returned to at least 80% of the patient’s best ever peak flow. Oral steroids can be stopped abruptly, even after courses of up to 3 weeks, but should not be stopped if the patient is on long-term oral steroids or if the patient’s asthma is deteriorating subjectively or objectively.

Referral.

Refer if:

• asthma remains poorly controlled or if the diagnosis is in doubt

• asthma is thought to involve occupational factors.

Self-management plan.

Note the patient’s predicted or best-ever PEFR, and calculate the 75% and 50% levels. These levels can be marked on a PEFR chart or on the peak flow meter itself. (Remember to recalculate the predicted or best-ever peak flow as the child grows.)

If the patient has an upper respiratory tract infection, is experiencing nocturnal wheezing or a persistent cough, or has a PEFR consistently between 50 and 75% of normal:

• Double the dose of the inhaled steroid for the number of days it takes to return to normal or until the PEFR returns to the previous baseline.

• Continue on this increased dose for at least the same number of days again. Then return to the maintenance treatment. Use a bronchodilator two puffs 4-hourly, or as appropriate.

If the patient is experiencing shortness of breath with normal activities, is increasing the use of bronchodilators or has a PEFR which is <50% of normal:

• Increase the dose of the inhaled steroids, as above.

• If arrangements have been made to use oral steroids at home:

– See Step 5 (p. 173).

– The patient should contact the GP within 24 hours.

• If oral steroids are not immediately available, the patient should contact the GP that day.

If experiencing difficulty with speaking, bronchodilators are ineffective or the PEFR is <30% of normal, the patient should contact the GP urgently, go directly to hospital or call 999.