The young person with asthma
CASE AIMS
After examining this case study the reader should be able to:
• Briefly explain the pathophysiology of choking and wheezing as symptoms of asthma.
• List the main causes of asthma in childhood.
• Demonstrate an understanding of the mode of action and side-effects of inhaled salbutamol and steroids in asthma.
• Explain why anticholinergics and leukotriene receptor antagonists may also have been considered in the treatment of asthma.
• Describe the role of the nurse in caring for the young person with asthma
• Outline the pharmacological treatment that would be prescribed in the acute phase of asthma.
CASE
Sam was diagnosed with asthma when he was 2 years old. He would awaken choking and wheezy, most nights. His parents were initially told that it was ‘teething’, but as his symptoms persisted he was investigated more thoroughly by his general practitioner (GP).
1 With reference to the pathophysiology of asthma, what would lead Sam to experience wheeziness and choking?
2 What are the main causes of asthma in childhood?
Sam was started on pressurized metered-dose inhaled salbutamol (a β2-adrenergic agonist), one puff as needed, and inhaled corticosteroids on a regular basis. This successfully controlled his symptoms for approximately three years.
3 Explain the modes of action and possible side-effects that salbutamol and inhaled corticosteroids will have on have on Sam
4 What other drugs may have been considered for the short- and long-term treatment of Sam’s asthma?
5 Outline the role of the nurse in Sam’s treatment and care
The family acquired a dog, Pancake, and Sam started school on a full-time basis. Within three weeks of getting Pancake, Sam had been admitted to hospital with an acute exacerbation of his asthma. Initially, his heart rate was 138bpm, his respiratory rate 34, he had dyspnoea with marked recession, a slight wheeze and inability to speak. Sam’s temperature was 38.4°C. On attaching an oxygen saturation monitor his saturations were 90%.
6 Outline the pharmacological treatment that would be prescribed for Sam in this acute phase of his illness
ANSWERS
1 With reference to the pathophysiology of asthma, what would lead Sam to experience wheeziness and choking?
A Asthma is a complex, multifactorial disease. Although airway reactivity, inflammation and increased mucus secretion are agreed on universally as the central components of asthma, the pathophysiology of each of these is complex (Lissauer and Clayden 2012).
WHEEZINESS
Following inhalation of a trigger, such as dog hair from Pancake, which is composed of protein alien to Sam’s body, a complex system of events are initiated.
• Firstly, helper T cells sensitive to the dog hair will bind with it, an action that stimulates B cells to produce specific antibodies in the form of immunoglobulin E (Ig E).
• Ig E in turn binds with a specific protein receptor on the surface of mast cells or basophils, which causes the cells to degranulate, releasing histamine, prostaglandins and leuko-trienes (also known as slow-reacting substances of anaphylaxis – SRS-A).
• SRS-A are primarily responsible for the contraction of smooth muscle in the bronchi and bronchioles, which leads to narrowing of the airways and an increase in airway resistance, which would cause Sam to wheeze (Rees et al. 2012).
CHOKING
Excessive mucus production is a universal symptom of asthma and is brought about by the action of histamine, prostaglandins and SRS-A which causes further narrowing of the airways. In 2002 a calcium-activated chloride channel (HCLCA1) was identified as being responsible for regulating excessive mucin production, which is thought to be a critical component of mucus in the airways. Mucus therefore fills the alveoli, inhibiting alveolar respiration and leading to the feeling of choking (Carroll et al. 2002)
2 What are the main causes of asthma in childhood?
A
• Genetics – there is irrefutable evidence to show that familial and genetic factors play a large part in childhood asthma (Van Bever 2009).
• Allergy – approximately 6% of childhood asthma is attributable to allergy to animal dander or foodstuffs, and 90% of these are allergic to dairy products, nuts or shellfish (Sohi and Warner 2008).
• Viral infections – infection with rhinovirus in infancy has been linked to future symptomology of asthma in childhood and early adulthood, while mycoplasma has been implicated in 20% of children admitted to hospital with asthma (Bizzintino et al. 2011).
• Obesity and oesophageal reflux – asthma in obese children may be as a result of inactivity rather than the obesity itself. However, there is a link between asthma and abnormal glucose and lipid metabolism that goes beyond the child’s basal metabolic rate (BMR) (Cotterell et al. 2011).
• Hygiene hypothesis – this is a misleading title, as this notion is actually linked to a presumed decline in exposure to dirty environments. This hypothesis has been debated consistently and linked to the current obsession of western civilizations with hygiene and cleanliness. More recent work identified that while exposure in childhood to farmyard living can confer protection from respiratory allergies, the obverse has not yet been identified – i.e. that living in clean cities can actually cause such allergies (Van Mutius 2010).
• Passive smoking – smoking around children has been identified as a possible cause of their asthma, although the mechanism is vaguely defined. While there is no specific causal link, the lung development of infants of mothers who smoked during pregnancy has been shown to be affected (NICE 2008; Becker and Kozyrskyj 2010).
• Emotion and psychological factors – it has long been identified that there is a link between emotion and asthma development. Establishing what the link is has become the main focus for many researchers (Ritz et al. 2010).
3 Explain the modes of action and possible side-effects that salbutamol and inhaled corticosteroids will have on have on Sam
B2-ADRENERGIC RECEPTOR AGONISTS
Short-acting β2-adrenergic receptor agonists (SABAs) such as salbutamol are commonly known as ‘relievers’ or ‘rescue medications’, which act in minutes and last up to four hours. They work by relaxing the smooth muscle of the bronchi and bronchioles (bronchodilation) by potentiating the effect of β2-adrenergic receptors in the heart and lungs which are activated by the sympathetic nervous system. They also aid in clearing mucus, but do not decrease mucosal swelling (Rees et al. 2012). The impact of their therapeutic mechanism leads patients to complain of tachycardia, tremor, palpitations, nausea and anxiety (Sweetman 2011).
For a more sustained mode of action, longer-acting β2-adrenergic receptor agonists (LABAs) such as salmeterol (licensed for children over 4 years) or formoterol (licensed for children over 6 years) are available, which again act in minutes but last for up to 12 hours (BMJ Group 2011).
STEROIDS
Steroids, commonly referred to as ‘preventors’, are most effective if taken on a regular basis. Their mode of action is to limit the number of SRS-A being released and to interfere with their cytokine action, leading to a reduction in mucous membrane inflammation.
Glucocorticoids are the second step in the SIGN ‘Stepwise’ approach (2012) and are the most effective first-line prophylactic therapy. Inhaled forms are usually used except in the case of severe persistent disease, in which case oral steroids may be needed. Inhaled formulations may be used once or twice daily, depending on the severity of symptoms.
There are a variety of inhaled formulations that include budesonide, which is licensed from 3 months of age and may be mixed with either terbutaline, salbutamol or ipratropium, and fluticasone, which is available for use with young people aged 16 years or older.
Side-effects of inhaled steroids tend to be muted and include impaired growth, adrenal suppression and altered bone metabolism if used in high doses. Oral steroids conversely have major side-effects that include immune-suppression, fluid retention, discolouration or thinning of the skin, hyperglycaemia, redistribution of fat and hypothalamic-pituitary-adrenal suppression. These adverse effects can be mitigated by tapering the lowest effective dose and by alternate-day administration (NICE 2007).
4 What other drugs may have been considered for the short- and long-term treatment of Sam’s asthma?
A ANTICHOLINERGICS
These are a group of drugs that influence the parasympathetic nervous system in blocking the effect of the neurotransmitter acetylcholine, leading to an increase in the diameter of bronchi and bronchioles. Ipratropium bromide is the most widely used in childhood and provides additional benefit when used in combination with SABAs in those with moderate or severe symptoms. Anticholinergic bronchodilators can also be used if a person cannot tolerate a SABA and their main side-effects tend to be gastrointestinal upset, dry mouth, anxiety, coughing and headache.
Table 2.1 Stepwise approach to asthma medications
| Intermittent asthma | Persistent asthma: daily medication | |||||
| Age | Step 1 | Step 2 | Step 3 | Step 4 | Step 5 | Step 6 |
| < 5 years | Rapid-acting beta2-agonist prn | Low-dose inhaled corticosteroid (ICS) Alternate regimen: cromolyn or montelukast | Medium-dose ICS | Medium-dose ICS plus either long-acting beta2-agonist (LABA) or montelukast | High-dose ICS plus either LABA or montelukast | High-dose ICS plus either LABA or montelukast; oral systemic corticosteroid |
| 5–11 years | Rapid-acting beta2-agonist prn | Low-dose ICS Alternate regimen: cromolyn, leukotriene receptor antagonist (LTRA), or theophylline | Either low-dose ICS plus either LABA, LTRA, or theophylline or medium-dose ICS | Medium-dose ICS plus LABA Alternate regimen: medium-dose ICS plus either LTRA or theophylline | High-dose ICS plus LABA Alternate regimen: high-dose ICS plus either LABA or theophylline | High-dose ICS plus LABA plus oral systemic corticosteroid Alternate regimen: high-dose ICS plus LRTA or theophylline plus systemic corticosteroid |
| 12 years or older | Rapid-acting beta2-agonist as needed | Low-dose ICS Alternate regimen: cromolyn, LTRA, or theophylline | Low-dose ICS plus LABA or medium-dose ICS Alternate regimen: low-dose ICS plus either LTRA, theophylline, or zileuton | Medium-dose ICS plus LABA Alternate regimen: medium-dose ICS plus either LTRA, theophylline, or zileuton | High-dose ICS plus LABA (and consider omalizumab for patients with allergies | High-dose ICS plus either LABA plus oral corticosteroid (and consider omalizumab for patients with allergies) |
LEUKOTRIENE RECEPTOR ANTAGONISTS
Leukotriene receptor antagonists (also known as leukasts) are one of the newest drugs to be introduced into the arsenal for fighting asthma. Leukotrienes are part of the inflammatory mediators that induce broncho-constriction, so these drugs inhibit their action by blocking the receptor sites in lung tissue. Leukotriene receptor antagonists (such as zafirlukast, montelukast and zileuton) are an alternative to inhaled glucocorticoids, but are not preferred. They may also be used in addition to inhaled glucocorticoids but in this role are second line to LABAs. There are few recognized side-effects, although the British National Formulary for Children (BMJ Group 2011) cautions against the development of eosinophilia, vasculitic rash, worsening pulmonary symptoms, cardiac complications or peripheral neuropathy.
5 Outline the role of the nurse in Sam’s treatment and care
A The nurse has a number of roles in Sam’s treatment and care, including the following.
• Assessment of Sam’s and his family’s lifestyle.
• Involving Sam in decision-making to improve concordance.
• Ascertaining whether the asthma symptoms are affecting Sam’s activity during the day or sleeping at night.
• Taking peak expiratory flow rate (PEFR) (in children aged over 5 years), using the best of three readings, expressed as a percentage of personal best PEFR.
• Measuring the amount and/or speed of air that can be inspired and expired (spirometry).
• Measuring height and weight annually to monitor correct prescribing dosage and potential drug impact on both.
• Measuring oxygen saturation – low oxygen saturations (<92%) after initial broncho-dilator therapy indicate a more severe subgroup of patients. Children with life-threatening asthma or SpO2 <92% should receive high flow oxygen via facemask or nasal cannula.
• Giving calm reassurance at all times.
• Assessment of inhaler technique on a six-monthly basis.
• Educating Sam and his parents about asthma and the need for treatment even when no symptoms are present.
6 Outline the treatment that would be prescribed for Sam in this acute phase of his illness
A In the acute phase, Sam’s treatment would depend on the severity of his asthma. His treatment would be in line with the British Thoracic Society/Scottish Intercollegiate Guidelines Network (SIGN 2012). He would be commenced on oxygen at a high flow rate of 10–15L via a facemask with a reservoir bag, and given nebulized salbutamol 5mg and ipratropium bromide 250mcg made up to 4ml with normal saline; a flow rate of 6–8L/min of oxygen would be required. This would be repeated every 20–30 minutes as necessary to maintain Sam’s SpO2 above 92%. If he is not responding as well as expected, intravenous (IV) hydrocortisone 4mg/kg four-hourly to a maximum of 200mg/day would be prescribed.
If Sam’s lack of improvement continued, the doctor would prescribe IV salbutamol 15mcg/kg followed by IV infusion of 1–5mcg/kg/min as required. To ensure that arrhythmias from this treatment were detected as soon as possible, Sam would be nursed on a cardiac monitor.
KEY POINTS
• Asthma affects 1 in 10 children and is the most common childhood condition in the UK for which GPs are consulted.
• The condition is bi-phasic in nature and mirrors the inflammatory process.
• Current treatment revolves around a ‘stepwise’ approach that starts with β2-receptor agonists in addition to inhaled steroids.
• There is an array of both short- and long-term inhaled treatments available.
• The role of the nurse in relation to this condition is wide and includes, for example, assessment of the individual and their lifestyle, involving the child or young person and their family in decision-making to increase concordance, and educating parents and young people about their asthma and the necessity for treatment even when they are not suffering any symptoms.
• Inhaler technique should be assessed six-monthly, in addition to height and weight.
• Nurses should know when to refer to secondary care environments.
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