3: Asthma

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Last modified 22/06/2015

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Case 3 Asthma

Description of asthma

Definition

Asthma is a chronic inflammatory disease of the airways, characterised by acute exacerbations of reversible airway obstruction. The condition was formerly divided into two main types – extrinsic and intrinsic asthma. These classifications have since changed. Asthma is now separated into more specific aetiological subtypes, including, for example, allergic, exercise-induced, nocturnal, aspirin-sensitive and occupational asthma.

This distressing, often disabling, and sometimes fatal disorder affects around ten per cent of the Australian population.¹ A slightly higher prevalence rate is evident among adult women (eleven per cent) and among the 15–24 and 75 years and over age groups (eleven per cent). Higher rates of asthma are also observed among socially disadvantaged, unemployed and Indigenous populations.¹

Aetiology and pathophysiology

The aetiology of asthma is multifactorial, with genetic and familial factors playing a major part in the pathogenesis of the disease. There is some suggestion that the growing prevalence of asthma is also due to a number of environmental contacts, such as vaccination, early introduction of foods, early exposure to antibiotics and food additives,^2,³ but there are insufficient data to support these theories. Emerging evidence does indicate that exposure to infectious agents may be a risk factor; one recent longitudinal study reported significantly higher odds of asthma and respiratory wheeze among 5-year-old children who reported severe respiratory infections during infancy, particularly those with atopy.⁴ Other factors linked to the development of asthma are obesity, exposure to household allergens (e.g. dust mite, cockroaches, pets), omega 3 fatty acid intake and perinatal issues (e.g. lack of breastfeeding, poor maternal nutrition, young maternal age, prematurity, low birthweight).^3,⁵ Evidence linking nutrient deficiency (e.g. vitamin C, vitamin E) with asthma is not convincing.^6,⁷

The acute onset of asthma in susceptible individuals can be initiated by a range of allergic and non-allergic triggers, including household allergens (e.g. dust mite, cockroaches, animal dander), respiratory irritants (e.g. air pollution, cigarette smoke, perfumes, cleaning agents, sulfur dioxide), grass and tree pollens, occupational irritants (e.g. latex, solder, flour), hormonal changes, exercise, emotions (e.g. anger, anxiety, excitement), respiratory infections, cold air, aspirin and gastro-oesophageal reflux disease.^3,⁸ It is not yet established how these factors trigger respiratory distress, although the prevailing theory suggests that heightened inflammatory activity could be a precipitating factor. The predominance of T-helper cell type 2 (Th2) activity observed in asthmatics and the subsequent increase in pro-inflammatory cytokine levels, airway eosinophilia and immunoglobulin (IgE) production, all appear to promote the development of smooth muscle hypertrophy and airway remodelling.⁹ These changes lead to airway hyper-responsiveness, which, upon exposure to any one of the aforementioned triggers, causes airway inflammation, submucosal oedema, increased mucus production, bronchoconstriction, mucus plugging and respiratory distress.^3,⁹

Clinical manifestations

People with mild asthma are normally asymptomatic between exacerbations. In more severe cases of asthma, and during acute exacerbations of asthma, people typically present with dyspnoea, tachypnoea, chest tightness, cough, audible wheezing and anxiety. As airway obstruction progresses, and oxygen exchange diminishes, more serious manifestations begin to emerge, including hypoxia, cyanosis and altered consciousness, and at worst, respiratory failure and death.^3,⁸

Clinical case

23-year-old woman with exercise-induced asthma

Rapport

Adopt the practitioner strategies and behaviours highlighted in Table 2.1 (chapter 2) to improve client trust, communication and rapport, and the accuracy and comprehensiveness of the clinical assessment.

Assessment

Once measures have been put into place to build client–practitioner rapport, the clinician can begin the clinical assessment.

Health history

History of presenting condition

A 23-year-old woman presents to her CAM practitioner with concerns about relapsing asthma. The client developed mild asthma at the age of 5, that went into remission in mid-adolescence. In the past 12 months, the signs of asthma have returned, specifically, wheezing, coughing, dyspnoea and chest tightness. These symptoms, which manifest at least 2–3 times a week, are mild and short-lived, and are no more than 10–15 minutes in duration. The symptoms, relieved by salbutamol inhaler and rest, are infrequently aggravated by cold air and frequently triggered by intense exercise. The exercise-induced asthma is particularly problematic for the client as it is interfering with her ability to perform as a personal trainer. The client is deeply concerned that without adequate treatment, she may have to turn to another career.

Medical history

Lifestyle history

Diet and fluid intake
Breakfast	Wholemeal toast with low-fat cream cheese, coffee.
Morning tea	Protein bar, banana, walnuts.
Lunch	Tossed salad or wholemeal sandwich with turkey or chicken, tomato, low-fat cheese and lettuce.
Afternoon tea	150 g vanilla yoghurt.
Dinner	Egg white omelette with tomato and cheese, grilled salmon or whiting with carrots and beans, stirfry with chicken breast, carrots, capsicum and onion.
Fluid intake	1–2 cups of instant coffee a day, 7–8 cups of water a day.
Food frequency
Fruit	1–2 serves daily
Vegetables	2–3 serves daily
Dairy	2–3 serves daily
Cereals	4–5 serves daily
Red meat	1 serve a week
Chicken	6 serves a week
Fish	1 serve a week
Takeaway/fast food	0–1 times a week

Quality and duration of sleep

Continuous sleep, average duration is 6–7 hours. In winter, sleep is often broken due to cold-air induced exacerbations of asthma.

Frequency and duration of exercise

Client is very active. Drives to work, but participates in personal training activities (e.g. weights, circuit) more than 4 hours a day; recently had to cease aerobic training due to asthma. Engages in incidental exercise (e.g. cleaning, cooking, work-related walking) more than 3 hours a day and sedentary activities less than 2 hours a day.

Socioeconomic background

The client is German-born with German-born parents. She completed tertiary education 18 months ago and has since been employed as a full-time personal trainer, which she enjoys. The client lives with her supportive partner in a new home in the outer suburbs, away from arterial roads and heavy industry. She has no children, nor any firm religious or cultural beliefs.

Physical examination

Inspection

Client is able to maintain a normal conversation in a sitting and lying position without becoming short of breath. Respiratory rate (16 breaths per minute), rhythm (regular), depth and effort are unremarkable. There are no visible signs of respiratory distress (e.g. accessory muscle use), hypoxia (e.g. clubbing or cyanosis), oropharyngeal inflammation, chest deformities or scarring.

Olfaction

Mild halitosis is evident. The client denies any sinus, chest or oral infections.

Palpation

Paranasal sinuses, lymph nodes and chest wall are non-tender and unremarkable. Chest expansion is symmetrical and tactile fremitus is normal.

Percussion

All lung fields are resonant; no abnormal percussive tones were detected.

Auscultation

Vesicular breath sounds are heard equally over all lung fields. Mild late expiratory polyphonic wheeze is also evident across all lung fields. Bronchophony, aegophony and whispered pectoriloquy are absent.

Additional signs

Client is afebrile (36.7°C, per oral) and of normal weight (BMI is 21.4 kg/m², waist circumference is 67 cm).

Clinical assessment tools

The asthma control scoring system (ACSS) revealed a clinical subscore of twenty per cent (a measure of symptom frequency, physical limitation and rescue medication use), a physiological subscore of eighty per cent (a measure of peak expiratory flow rate), and an inflammatory subscore of eighty per cent (a measure of airway eosinophil count).¹⁰ This provided a mean global asthma control score of 60 per cent, signifying modest asthma control and moderate asthma severity (a higher percentage score indicates better control and reduced severity).

Diagnostics

CAM practitioners may request, perform and/or interpret findings from a range of diagnostic tests in order to add valuable data to the pool of clinical information. While several investigations are pertinent to this case (as described below), the decision to use these tests should be considered alongside factors such as cost, convenience, comfort, turnaround time, access, practitioner competence and scope of practice, and history of previous investigations.

Pathology tests

Eosinophil count

This count is a useful marker of asthma activity because activated eosinophils release histamine, which triggers bronchial smooth muscle contraction and mucus production, all of which are implicated in the pathogenesis of asthma.⁹

Immunoglobulin E (IgE)

IgE is an antibody primarily involved in allergic reactions. When IgE is cross-linked with an antigen, it stimulates the release of vasoactive substances (e.g. histamine) from basophils and mast cells. This results in smooth muscle contraction, increased vascular permeability and inflammation,¹¹ and the subsequent manifestation of symptoms such as wheeze and dyspnoea. Elevated levels of serum IgE are positively associated with the severity of asthma.¹²

Plasma or red cell fatty acid analysis

This assesses the concentration of fatty acids within the plasma or erythrocyte, including omega 3, omega 6 and omega 9 polyunsaturated fatty acids, saturated fatty acids and trans fatty acids. Given that high dietary omega 3 fatty acid intake is associated with decreased odds of developing wheeze and asthma when compared with lower omega 3 fatty acid intake,⁵ this test may help to determine whether poor omega 3 fatty acid consumption is a contributing factor in asthma.

Sputum culture and sensitivity testing

These tests may be warranted if infectious triggers of asthma are suspected, in particular, the presence of bacterial, viral or fungal infections of the respiratory tract.¹¹

Radiology tests

It is not routine practice to use medical imaging in the diagnosis of asthma. Chest X-ray and CT scans may be indicated, however, in complicated asthma, atypical presentations of asthma, and/or suspicions of more serious pathology.⁷

Functional tests

Pulmonary function tests (PFTs)

PFTs are often used to evaluate the presence and severity of asthma. The PFT can incorporate any number of different measures of lung volume and capacity, including total lung capacity, tidal volume, maximal mid-expiratory flow (MMEF), maximal volume ventilation (MVV), peak inspiratory flow rate (PIFR), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), and peak expiratory flow rate (PEFR). Reductions in the latter three measures are often evident in obstructive airway diseases such as asthma.¹¹

Invasive tests

Invasive procedures are not typically used in the diagnosis of asthma unless there are suspicions of serious underlying pathology.

Miscellaneous tests

Bronchial provocation tests use either direct (e.g. inhaled histamine or methacholine) or indirect (e.g. exercise, cold air hyperventilation) stimuli to trigger bronchial smooth muscle contraction in hyperresponsive airways. There is some debate as to whether the results of these tests are specific to a diagnosis of asthma.^13,¹⁴

Diagnosis

Clusters of data extracted from the health history, clinical examination and pertinent diagnostic test results point towards the following differential CAM diagnoses.

• Dyspnoea (actual), secondary to asthma, related to genetic predisposition (client has a family history of asthma), chronic inflammation (if supported by an elevated serum IgE and eosinophil count), exercise (asthma symptoms are triggered by intense exercise), cold air (asthma symptoms are aggravated by cold air), and/or low omega 3 fatty acid intake (low omega 3 fatty acid intake is associated with increased odds of developing asthma; while the client reports the consumption of approximately one serve of fish a week, dietary recall bias cannot be excluded).

• Exercise intolerance (actual), secondary to asthma, related to genetic predisposition, chronic inflammation, exercise, cold air and/or low omega 3 fatty acid intake.

Planning

The goals and expected outcomes that best serve the client’s needs and that are most relevant to the presenting case (as determined by the clinical assessment and CAM diagnoses) are as follows.

Goals

1. Client will report a reduction in acute asthmatic episodes (client is concerned about the relapsing asthma).

2. Client will experience an improvement in exercise tolerance (client has expressed concern about the asthma interfering with personal training activities).

Expected outcomes

Based on the degree of improvement reported in clinical studies that have used CAM interventions for the management of asthma,^15,¹⁶ the following are anticipated.

1. Client will demonstrate a forty per cent reduction in the baseline number of asthma attacks experienced per week in 6 weeks or by dd/mm/yyyy (measured by asthma diary and ACSS clinical assessment subscore).

2. Client will exhibit a forty per cent decrease in baseline asthma severity in 6 weeks or by dd/mm/yyyy (measured by mean global asthma control score).

3. Client will report a forty per cent increase in the baseline duration of exacerbation-free exercise per week in 3 weeks or by dd/mm/yyyy (measured by exercise diary).

Application

The range of interventions reported in the CAM literature that may be used in the treatment of asthma are appraised below.

Diet

Low-calorie diet (Level I, Strength C, Direction +)

As previously stated, there are a number of factors that elevate a person’s risk of developing asthma. A risk factor that is generally responsive to dietary change is obesity. There is, for instance, convincing evidence that high body weight at birth and/or during middle childhood increases the risk of developing asthma.¹⁷ Whether weight-reduction strategies are able to reverse this risk or improve asthma outcomes requires evidence from intervention studies. According to a Cochrane review, only one RCT has explored this hypothesis. The trial found the consumption of a low-energy diet plus education for 14 weeks to be statistically significantly superior to normal diet plus education at improving FEV₁, FVC and rescue medication use in obese people with asthma.¹⁸ Given that low-calorie diets also reduce serum levels of inflammatory markers¹⁹ suggests that the low-energy diet could have improved respiratory function via an anti-inflammatory effect.