Managing severe asthma in adults: what GPs need to know

In the first of a new miniseries of articles exploring management of complex asthma presentations, GP and respiratory specialist Dr Fiona Mosgrove explains the key issues when managing adult patients with severe asthma

What factors tend to make asthma severe?

Severe asthma occurs in a small percentage of asthma patients who continue to have symptoms and exacerbations requiring treatment with oral corticosteroids, despite concordance with maximal medical treatment.

These patients have such a high burden of inflammation in their airways that inhaled steroids and other treatments are insufficient to gain control of it. Severe asthma is often associated with raised levels of IgE and allergen specific IgE, blood eosinophils and fractional exhaled nitric oxide (FeNO).

There are several forms of severe asthma. One important form is that still often called ‘brittle asthma’, a term adopted in the 1970s to describe specific phenotypes of asthma and split into two subtypes. Type 1 was defined as having large swings in peak flow variability throughout the day, Type 2 as good asthma control in the background with very sudden and severe exacerbations.¹

Neither subtype of brittle asthma is associated with specific pathophysiological changes, and both are now considered likely to be subtypes within severe asthma. Type 1 effectively describes what happens in patients who have persistent uncontrolled inflammation, and Type 2 is suspected in patients who have elevated biomarkers but few symptoms; it may be the case for some patients that symptoms do not always correlate with inflammation, while some patients have very minimal symptoms but have grumbling inflammation and take very little extra inflammatory stimulus to precipitate an exacerbation. What we recognise in clinical practice in primary care as brittle asthma is that which is challenging to treat due to wide variability in symptoms day to day or, more alarmingly, sudden onset of severe or life-threatening exacerbations.

How can GPs mitigate these factors?

The main role of GPs and primary care teams is to identify patients with poor control who are on medium- or high-dose steroid inhalers, using lots of puffs of reliever inhaler and having frequent exacerbations requiring treatment with oral steroids. These patients will often either have difficult-to-treat or severe asthma and it is a matter of working out which, if any, modifiable risk factors can be manipulated to improve control. If manipulation of a modifiable risk factor achieves control, then this is difficult to treat, rather than severe asthma. Patients with brittle asthma are usually at the more severe end of the spectrum.

Checking concordance and inhaler technique, treating any nasal disease or reflux, identifying and avoiding triggers where relevant and advising regarding smoking cessation are some of the most important things that can be done, but early referral is probably wise.

What self-management plans should these patients have in place?

It is important that the self-management plan is useful for and usable by the patient and that it is referred to and updated during consultations. My own typical practice for severe asthma is to make sure they know that if they exacerbate, they need prompt treatment with oral corticosteroids; increasing puffs of inhaler over and above their maintenance dose is unlikely to make any difference. It is also important to encourage patients to have confidence in recognising their early signs of exacerbation. We know from diary studies that symptoms increase in the 7-10 days before an exacerbation,²so it is helpful to tell patients this – eg, ‘if you are feeling more symptomatic for a few days and it’s not settling, that probably means you are working towards a flare up’. Peak flow is only useful and worth including in the self-management plan if the patient finds it helpful and uses it as part of their routine management – eg, they have symptoms, then confirm their peak flow is low.

What is the role of rescue packs and what should be prescribed?

The appropriateness of rescue packs can be a contentious issue in asthma patients. With the introduction of newer treatments, we are moving away from the old culture of ‘steroids and antibiotics’ being a core part of asthma exacerbation treatment, towards one that views these as a reflection of poorly controlled inflammation and a need to review and optimise treatment.

Patients with severe asthma who know their condition well and can confidently identify exacerbations might manage to safely have a rescue pack of steroids at home (typically 40mg daily for 5 days) to allow them to start treatment promptly. This may be particularly relevant for patients with brittle asthma. I would usually establish a few rules around rescue packs, however, such as asking the patient to let the practice know they are starting them so we can review treatment, if necessary, depending on the scenario. For example, they may need referral to the asthma clinic. It is also important to reinforce advice on worsening symptoms.

Antibiotics are not usually required for treatment of asthma exacerbations, as these are typically inflammatory events and oral corticosteroid is the treatment for inflammation. Patients who have dark yellow or green sputum, suggestive of bacterial infection, may benefit from the addition of an antibiotic to the oral corticosteroids. (Though not a definite indicator of bacterial infection, the dark yellow/green colour is due to myeloperoxidase released from neutrophils, which are associated with response to bacterial infection; therefore antibiotics might be considered, particularly in patients with a history of recurrent exacerbations with green sputum. The other option is to treat with steroids and ask the patient to report if symptoms do not resolve, or to send a sputum culture.)

How should we respond to requests for home nebulisers?

I tend to avoid endorsing nebulisers for asthma patients to use at home and increasingly practices and severe asthma centres do not have a supply of them to give out to patients (though patients may purchase them for themselves).

For long term management of asthma, salbutamol multidosed via spacer is as effective as nebulised salbutamol, but some patients feel that the nebuliser is more effective. This is particularly the case if they have had a previous good response to a nebuliser administered in hospital, for example.

The guidelines generally advise the nebulisers be reserved for acute asthma, particularly in the hospital setting, or where patients cannot use inhalers properly – eg, due to cognitive or musculoskeletal issues.

The main worry with nebulisers is that patients become reliant on them for symptom relief and neglect their background treatment, which is the important part in terms of controlling airway inflammation. They can also expose patients to much higher doses of salbutamol.

What unusual asthma complications might be the cause of brittle or severe asthma?

More severe asthma can be complicated by an allergic response to aspergillus, known as allergic broncho-pulmonary aspergillosis (ABPA), which presents with exacerbations and viscous sputum which is typically extremely difficult to expectorate. This is diagnosed on CT scan and is usually picked up at severe asthma clinic, rather than in primary care, but the history of viscous sputum might raise ABPA as a possibility in primary care. Eosinophilic granulomatosis with polyangiitis (EGPA, formerly known as Churg-Strauss syndrome) is one of the other conditions we often screen for in the asthma clinic. It presents as asthma and allergic rhinitis or nasal polyps and, as the disease evolves, a high eosinophil count and vasculitis can develop. Eosinophil counts above 1 would raise suspicion of this. The other common conditions that can occur in severe asthmatics and may also mimic asthma are breathing pattern disorder and inducible laryngeal obstruction (ILO). Breathing pattern disorder is highly prevalent in severely asthmatic patients and can cause significant breathlessness. ILO is paradoxical adduction of the vocal cords giving rise to a feeling of breathlessness, often higher up in the throat, rather than the chest and can produce a stridulent noise which patients and clinicians may mistake for wheeze.

Dr Fiona Mosgrove is a GPwSI in respiratory medicine in Aberdeen