Managing paediatric asthma in primary care
Asthma is a heterogeneous disease characterized by chronic airway inflammation, manifesting with respiratory symptoms such as wheeze which varies in frequency and severity over time. It is estimated that about 20 percent of children in Singapore suffer from asthma. Due to the condition being so common, GPs will be dealing with paediatric asthma frequently in their practice.
Diagnosing paediatric asthma
Making an accurate diagnosis of asthma in children requires a thorough history from the patient and parent. One should look for a history of recurrent respiratory symptoms (wheeze, cough, dyspnoea, chest tightness) which are typically worse at night or early morning. These may be exacerbated by exercise, viral infection, smoke, dust, pets, mold, dampness, weather changes, laughing, crying, or allergens.
Also, a personal history of atopy (eczema, food allergy, allergic rhinitis) and family history of asthma or atopic diseases are risk factors for the development of asthma.
Physical examination may be normal, or reveal features such as chest hyperinflation or wheeze on chest auscultation. Other clues for atopy such as eczema or signs of allergic rhinitis should be sought.
Further supporting tests
Although the diagnosis of asthma is mainly obtained from the history of the child’s presenting complaints, there are tests which can help support the diagnosis. Children aged ≥5 years can attempt spirometry as they can follow test instructions and form a secure seal around the mouthpiece of a spirometer while doing so. The presence of airflow limitation by way of a low forced expiratory volume in one second (FEV1), and a low FEV1:FVC ratio (where FVC is the forced vital capacity) suggests the presence of asthma.
In addition, a positive bronchodilator reversibility test with salbutamol demonstrating an increase in FEV1 of ≥12 percent predicted constitutes further evidence of the diagnosis. Testing for bronchodilator reversibility in children younger than 5 years old is possible by impulse oscillometry, but this is only available at tertiary centres.
While peak expiratory flow (PEF) measurements in children may help support a suspected diagnosis of asthma, the normal range for PEF is wide in children, so it is more useful for monitoring asthma rather than making a diagnosis.
Other tools for supporting the diagnosis include fractional exhaled nitric oxide to detect eosinophilic airway inflammation. This tool has become more widely available and may predict the development of asthma in preschool children with recurrent cough and wheeze.
In terms of making the diagnosis of asthma, it is important that the physician has confirmed the presence of episodic symptoms of reversible airflow obstruction as detailed previously before making the diagnosis of asthma. It is also important to ensure that other conditions that may mimic asthma are excluded, such as bronchiectasis or inhaled foreign body.
Young children under the age of five present a diagnostic dilemma. Wheeze is a common symptom with respiratory viral infection. In infants up to a year old who present with wheeze, bronchiolitis is a more likely diagnosis, particularly if the wheeze is preceded by coryzal symptoms. Also, the majority of preschool children (age 2–5 years) presenting with recurrent viral-induced wheezing will not develop asthma, especially those with no personal or family history of atopy. These children will generally “grow out” of their symptoms. The Asthma Predictive Index is one example of a risk profile tool that will help identify those at risk of developing school-age asthma.
Managing paediatric asthma
The approach to the management of and long-term treatment strategy for children with asthma should be a holistic one ─ with the aim of achieving good disease control, so that the patient can lead as normal a lifestyle as possible.
Key approaches to good disease control include:
· Patient and parent education
· Identification and avoidance of triggers (for example, exposure to household smoking or other allergens)
· Use of appropriate medication (including correct technique and appropriate delivery of medication – young children should have inhaled medication delivered via a spacer, with a mask for those too young to place a good seal over the spacer mouthpiece)
· Regular monitoring
Comorbidities such as obesity and allergic rhinitis should also be managed.
Good control is essential to reduce the future risk of asthma morbidity such as frequent and severe asthma exacerbations. A written asthma action plan should be in place to instruct parents about the correct medications to give if an exacerbation occurs.
Patients should be reviewed regularly (every 3 months) to step up or step down on medications. Short-acting beta2-agonists should be the first step of therapeutic management. If preventers are needed, low-dose inhaled corticosteroids are preferred, stepping up to moderate-dose inhaled steroids after 3 months if control is not achieved. For children ≥4 years, long-acting beta2-agonists can be given in combination with inhaled corticosteroids if control is not achieved. A leukotriene receptor antagonist can be added on, if needed, to help achieve control.
Patients should be referred to a tertiary unit if there are doubts about the diagnosis of asthma, for example if treatment escalation does not result in improvement of the child’s symptoms, or if there are signs of concern on examination such as finger clubbing. Patients should also be referred if symptoms or exacerbations remain uncontrolled despite moderate-dose inhaled corticosteroids (with or without long-acting beta agonists). Any concerns about side effects of treatment such as growth delay or frequent need for oral corticosteroids to treat exacerbations should also warrant a referral.
Preschoolers should be referred for further evaluation if there are associated failure to thrive, very early onset of symptoms (for example, in the neonatal period), continuous wheezing, or if there are any focal signs on chest examination.
One main challenge in managing paediatric asthma is adherence to preventer therapy. Preventer therapy usually requires children to take their medication at least twice daily, and a significant proportion of patients will not fully adhere to their treatment regimen.
Both patient and parent factors have a role in this: for instance, parents may worry about side effects of long-term inhaled steroid therapy (whether real or perceived), and may choose to stop medications on their own accord. Adolescent patients may not see the need for daily medication, or they may be in denial about their diagnosis, leading to poor or nonadherence to treatment.
Educating and counselling parents and patients on the need for adherence to a prescribed treatment regimen is key to success. Safety and efficacy of treatment should be emphasized, and any concerns addressed.
Paediatric asthma should be approached in a holistic manner. Education is a cornerstone in management; working together with the patient and family to ensure a clear plan of management is key to optimizing treatment.