Most asthma responds readily to treatment. However, an estimated 5 per cent of cases fail to respond and need additional evaluation and treatment.
The European Respiratory Society defines difficult asthma as ‘poorly controlled in terms of chronic symptoms, with episodic exacerbations, persistent and variable airway obstruction and continued requirement for short-acting beta-2 agonists and a reasonable dose of inhaled corticosteroids’.
Recognising the symptoms
A patient with difficult asthma finds that it is poorly controlled despite three or more classes of anti-asthma treatment, has brittle asthma, has had numerous admissions or A&E attendances, has had previous episodes of life-threatening asthma, needs several courses of steroids in quick succession, has had poor concordance and adherence with repeat medication; and/or has co-morbidities.
A diagnosis of severe or difficult asthma must be founded on good evidence of asthma. The asthma may be severe and will need more intensive treatment. Smoking will make any airways disease worse.
Administering the right drug via the right device for the patient is a cornerstone of asthma management.Concordance and adherence is an issue. If the patient cannot master the inhaler technique then asthma symptoms will persist.
Difficult asthma can occur with mild, moderate or severe disease.
There may be discordance between reported symptoms and measurable severity of the asthma. This is where additional specialised help is likely to be useful in reconciling the mismatch.
Psychiatric co-morbidity can be a major contributor to difficulty in managing asthma. Anxiety will tend to make asthma symptoms worse.
Persistent asthma will also make a depressed patient more depressed. So, both parts of the problem should be treated.
Some patients may have secondary gain from persistent asthma symptoms.
Conditions such as rhino-sinusitis may need controlling.
Environmental allergens in the patient’s home or at work may contribute.
Gastro-oesophageal reflux disease might make asthma worse. Obesity and sleep apnoea also exacerbate asthma and weight loss should be advised.
If you have a patient with type-2 brittle asthma on your list you need a strategy that the patient can implement as soon as an attack starts. Patients with brittle asthma can go from being well to ill very quickly.
Difficult asthma gives rise to most of the major morbidity and mortality from asthma. Although a small subgroup of the total asthmatic population, patients with difficult asthma are important to recognise and refer appropriately.
Some issues can be dealt with in the GP surgery but others will benefit from hospital back-up.
Some hospitals have dedicated difficult asthma clinics that will systematically work through the issues detailed above with the patients.
The ‘rule of threes’ will help identify these patients. The first time you see a patient you treat them. If they return with the same symptoms you try a second treatment. If they come back a third time you probably need help from someone else. The rule of threes will prompt you to send the patient to the right specialist clinic.
Most patients will eventually achieve good control of their asthma. However, a small group will not and may need long-term intensive treatment with powerful agents such as immunosuppressive drugs.