History

Consider acute asthma when a child presents with signs of increase work of breathing, widespread wheezing and shortness of breath. There are other causes to consider such as mycoplasma pneumonia, aspiration, inhaled foreign body, and cardiac failure (Table 6.3.1). In the setting of a child with a previous history of asthma or where asthma seems the most likely diagnosis, one can perform a primary assessment of severity and institute the initial treatment at the onset of history taking.

Acute Chronic Bronchiolitis, mycoplasma Cystic fibrosis Allergy Cilial dyskinesia Aspiration Immune deficiency Heart failure Bronchiectasis Foreign body Airway abnormalities

It is important to understand the patterns of asthma in children – infrequent episodic, frequent episodic, and persistent.¹ The pattern of asthma determines the need for preventive therapy. When a child is discharged from the emergency department (ED) or ward, consideration of the child’s preventative treatment is essential.

Infrequent episodic asthma

Infrequent episodic asthma (IEA) is the most common pattern, accounting for 70 to 75% of children with asthma. In this pattern, children have isolated episodes of asthma lasting from 1 to 2 days up to 1 to 2 weeks, usually triggered by an upper respiratory tract infection (URTI) or an environmental allergen. The episodes are usually more than 6 to 8 weeks apart and these children are asymptomatic in the interval periods. They require management of the individual episode only and regular preventive therapy is unnecessary. Within this group there is a wide range of severity. Most are mild, but this group accounts for up to 60% of paediatric hospital admissions for asthma.¹

Frequent episodic asthma

Frequent episodic asthma (FEA) accounts for approximately 20% of childhood asthma. This pattern is similar to IEA but the interval between episodes is shorter, less than 6 to 8 weeks, and the children have only minimal symptoms, such as exercise-induced wheeze, in the interval period. These children may benefit from regular preventive therapy such as low dose (not greater than 400 mcg per day) inhaled corticosteroids or leukotriene antagonist. Commonly, these children are troubled through the winter months only and may require preventive treatment for that part of the year.¹

Persistent asthma

Persistent asthma (PA) accounts for 5–10% of childhood asthma. These children can have acute episodes like the categories above, but they also have symptoms on most days in the interval periods. These symptoms commonly include: sleep disturbance due to wheeze or cough, early morning chest tightness, exercise intolerance and spontaneous wheeze. Again, there is a wide range of severity in this group, ranging from those with mild symptoms 4 to 5 days per week readily controlled with low-dose corticosteroid preventive therapy, to those with frequent severe symptoms and abnormal lung function requiring intensive therapy.¹

Acute episode

Mortality from acute asthma is fortunately rare – confidential enquiry into deaths from asthma suggests that there are three major factors contributing to the death.

• The severity of the disease: most children who have died from asthma have persistent asthma; however, a minority of children who have died have only mild to moderate disease.^4,^14,¹⁵ Previous near fatal asthma, previous admission in the last year, previous admission to padiatric intensive care unit (PICU), heavy use of β₂ agonists, repeat attendances to the ED are all risk factors associated with risk of a severe attack, near fatal asthma or death.⁴

• Medical management: inadequate treatment steroids, heavy or increasing use of β₂ agonists, inadequate monitoring of the asthma and underuse of written asthma plans and delay in seeking help, have all been associated with deaths from asthma.^4,^14,¹⁵

• Psychological factors: non-adherence, poorly perceived symptoms, failure to attend clinics, conflict between child and parent or medical staff, family dysfunction are all risk factors associated with risk of death from asthma.^4,¹⁶

A child should be considered as ‘high risk’ when attending the ED with an acute exacerbation of their asthma when there is a combination of features of previous severe asthma and one or more adverse psychological factors.

Examination

The most important parameters in the assessment of the severity of acute childhood asthma are general appearance/mental state and work of breathing (accessory muscle use, recession), as indicated in Table 6.3.2. Initial SaO₂ in air, heart rate and ability to talk are helpful but less reliable additional features. Wheeze intensity, pulsus paradoxus, and peak expiratory flow rate are not reliable.² Clinical signs of acute asthma correlate poorly with the severity of the asthma attack and none of the signs in isolation are predictive of severity.⁴ Classification of an acute attack, using the NAC Australia guidelines¹ is as follows: