Asthma

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Introduction

Asthma is a relatively common condition that is characterised by at least partially reversible inflammation of the airways and reversible airway obstruction due to airway hyperreactivity. It can be acute, subacute or chronic and/or exercise induced

Asthma:

• Is a major noncommunicable disease (NCD), affecting both children and adults.
• Affected an estimated 262 million people in 2019 and caused 461000 deaths (1).
• Is the most common chronic disease among children.
• Inhaled medication can control asthma symptoms and allow people with asthma to lead a normal, active life.
• Avoiding asthma triggers can also help to reduce asthma symptoms.
• Most asthma-related deaths occur in low- and lower-middle income countries, where under-diagnosis and under-treatment is a challenge.

Epidemiology

Asthma is one of the most common chronic diseases in the world. It is a common pathology, affecting around 15% to 20% of people in developed countries and around 2% to 4% in less developed countries. It is significantly more common in children.

Image: Deaths from Asthma in 2012 per million persons. Statistics from WHO grouped by deciles. Lightest yellow 0-10 through to red 96-251

Asthma:

• Affected an estimated 262 million people in 2019 and caused 461000 deaths.
• May occur at any age (significantly more common in children), most patients with asthma experience their first symptoms before the age of 5 years old and about 66% are diagnosed before the age of 18 years.
• Almost 50% of children with asthma have a decrease in severity or disappearance of symptoms during early adulthood.
• Prevalence is greater in extreme of ages due to airway responsiveness and lower levels of lung function.
• In many countries, including the US, asthma kills one out of every 100,000 persons.
• Results in millions of school and workdays lost. In the US alone, close to 2 million asthmatics seek regular care in the emergency department, which also increases the costs of healthcare.

Aetiology

Inflammation plays a major role in asthma and involves multiple cell types and mediators. The factors that initiate the inflammatory process are complex and still under investigation. Genetic factors (eg cytokine response profiles) and environmental exposures (such as allergens, pollution, infections, microbes, stress) at a crucial time in the development of the immune system are known to be involved.             

Risk Factors

Include:

• Asthma is more likely if other family members also have asthma – particularly a close relative, such as a parent or sibling.
• Asthma is more likely in people who have other allergic conditions, egeczema and rhinitis (hay fever).
• Urbanisation is associated with increased asthma prevalence, probably due to multiple lifestyle factors.
• Events in early life affect the developing lungs and can increase the risk of asthma. Eg low-birth weight, prematurity, exposure to tobacco smoke and other sources of air pollution, viral respiratory infections.
• Exposure to a range of environmental allergens and irritants are also thought to increase the risk of asthma, eg indoor and outdoor air pollution, house dust mites, moulds, and occupational exposure to chemicals, fumes, or dust.
• Children and adults who are overweight or obese are at a greater risk of asthma.

Pathophysiology

Asthma is a condition of acute, fully reversible airway inflammation, often following exposure to an environmental trigger. The pathological process begins with the inhalation of an irritant (e.g., cold air) or an allergen (e.g., pollen), which then, due to bronchial hypersensitivity, leads to airway inflammation and an increase in mucus production. This leads to a significant increase in airway resistance, which is most pronounced on expiration.

Airway obstruction occurs due to the combination of:

1. Inflammatory cell infiltration.
2. Mucus hypersecretion with mucus plug formation.
3. Smooth muscle contraction.

These irreversible changes may become irreversible over time due to

1. Basement membrane thickening, collagen deposition, and epithelial desquamation.
2. Airway remodeling occurs in chronic disease with smooth muscle hypertrophy and hyperplasia.

If not corrected rapidly, asthma may become more difficult to treat, as the mucus production prevents the inhaled medication from reaching the mucosa. The inflammation also becomes more edematous. This process is resolved (in theory complete resolution is required in asthma, but in practice, this is not checked or tested) with beta-2 agonists (e.g., salbutamol, salmeterol, albuterol) and can be aided by muscarinic receptor antagonists (e.g., ipratropium bromide), which act to reduce the inflammation and relax the bronchial musculature, as well as reducing mucus production.

Clinical Presentation

The classical symptoms of asthma are wheeze, shortness of breath, chest tightness or difficulty breathing and cough. These symptoms are typically variable and can be absent for long periods of time, with possible episodic exacerbations often triggered by factors such as exercise, allergen or irritant exposure, cold air or viral respiratory infections.

The diagnosis of asthma is clinical and relies on the recognition of a characteristic pattern or respiratory symptoms and signs in the absence of an alternative explanation. Features that increase the probability of asthma are:

• More than one of the following symptoms: wheeze, cough, difficulty breathing and chest tightness
• Episodic symptoms that are worse at night and in the early morning, and occur in response to certain triggers, e.g. exercise, allergen exposure, cold air
• Personal history of an atopic disorder or family history of an atopic (allergic) disorder and/or asthma
• Widespread wheeze on auscultation

• Lung function tests are useful in the evaluation of a patient with asthma to assess the presence, severity and reversibility of the airflow obstruction. On spirometry an FEV1/FEV ratio less than 0.7 confirms obstruction. In asthmatic patients, there is usually a large bronchodilator response (typically an increase of at least 12-15% in FEV1) 3, and it is also typically an abnormally high variability of the peak expiratory flow. A normal spirometry, particularly if performed when the patient is asymptomatic, does not exclude the diagnosis of asthma
  

When does asthma become life threatening?

• Difficulty to catch a breath
• Difficulty talking and concentrating
• Difficulty talking and walking
• Cyanosis of skin especially around the mouth and finger areas
• Nasal flaring and constant wheeze

When these signs and symptoms presents, a person should be aware and are advice to consult with your general practitioner as soon as possible.

Investigations and Diagnosis

Diagnosis of asthma is confirmed based upon various factors:

• Medical History

The patient is initially asked to explain their various symptoms, including their description, frequency, duration and aggravating factors. Substance exposure may have also lead to the onset of asthmatic symptoms, in which case exposure to tobacco smoke, chemical fumes, dust or other airborne irritants is determined. Additional questioning may include relevant health problems, the patient’s occupation and medications that may cause airway irritation.

• Family History

If the patient has a family history of asthma or allergies, they are more likely to also suffer from asthmatic symptoms.

• Physical Assessment

Firstly, the patient’s nose, throat and upper airways will be examined for signs of asthma or allergies. Assessment of the patient’s respiratory rate and breathing pattern will be carried out in conjunction with auscultation (using a stethoscope) in order to listen for signs of asthma or allergies that may aid diagnosis. These signs include:

• Wheezing (high-pitched whistling sounds when the patient exhales)
• Coughing, chest tightness
• Shortness of breath (SOB)
• A runny nose
• Swollen nasal passages.

The patient’s skin will also be examined for signs of allergic skin conditions (e.g. eczema and hives).

• Diagnostic Tests

The following tests are used to assess the patient’s breathing as well as to monitor the effectiveness of asthma treatment.

Lung function tests:SpirometryPeak flow testing

Other tests:

• Allergy testing
• Bronchoprovocation
• Chest X-ray
• Electrocardiogram (ECG)
  

Treatment

The goal of the treatment is to control the symptoms, prevent exacerbations and loss of lung function and reduce associated mortality.

1. Drugs used for control of asthma depend on the severity of the disease. Short-acting β2-agonists can be used in patients with mild occasional symptoms. Inhaled steroids (oral steroids might be required in severe cases) and long-acting β2-agonists can be used for long-term control. Oxygen, short-acting β2-agonists, inhaled anticholinergics and systemic steroids are used in acute exacerbations.

• Short-acting beta 2-agonists (quick acting or rescue medicine): these drugs are used best to treat sudden and severe or new asthma symptoms as they open the airways and relieve symptoms within 20 minutes and lasts four to six hours. It can also be used before physical activity about 15-20 minutes before the time to prevent exercise-induced asthma.
• Long-acting beta 2-agonists: these drugs are not used to for a quick relief of asthma symptoms, instead they are used to control symptoms and their effect lasts 12 hours.

2, Mechanical ventilation may be necessary for severe exacerbations that do not respond to medical treatment. Non-pharmacological measures, such as smoking cessation and avoidance of occupational sensitisers, are also important.

3. Non-pharmacologic management, including asthma education on inhaler technique and self-monitoring, is vital.

Prognosis

Asthma is a disease with variable progression and severity of symptoms over time. The prognosis depends on the severity of the disease and the degree of control with treatment. Some patients can be symptom-free for long periods, whereas a few patients with severe persistent asthma develop progressive loss of lung function. Death due to asthma is very rare.

Even though asthma is a reversible disorder, poor lifestyle and lack of management can lead to airway remodeling that leads to chronic symptoms, which are disabling.

Physiotherapy Management

The majority of patients suffering from asthma will seek physiotherapy for dyspnoea and hyperventilation . Physiotherapists treat asthma in a variety of ways with the aim to improve breathing technique. Physiotherapy techniques for asthma are in addition to medication and should never be used as a replacement for prescribed medication, however may reduce the dosage required.

1. Breathing Retraining Techniques

Breathing techniques may have more benefit on mild – moderate asthma . The aim of breathing retraining is to normalise breathing patterns by stabilising respiratory rate and increasing expiratory airflow. Instructions are given from the physiotherapist on how to complete this technique, with the following components:

• Decreasing Breaths Taken (Reducing Respiratory Rate)
• Taking Smaller Breaths (Reducing Tidal Volume)
• Deep Breathing (Diaphragmatic breathing through use of abdominal muscles and lower thoracic chest movement)
• Breathing through the Nose (Nasal Breathing)
• Relaxation (Relaxed, controlled breathing)
• Decreasing Air Leaving (Decreased expiratory flow through pursed lip breathing)
• These retraining techniques help control breathing and reduce airflow turbulence, hyperinflation, variable breathing pattern and anxiety.
  

Buteyko Breathing Technique

• The Buteyko breathing technique is another breathing retraining technique; however it is specific to reducing hyperinflation. It was developed based on the theory that asthmatic bronchospasm is caused by hyperventilation, leading to a low PaCO₂ and therefore all asthmatic symptoms are due to this. The narrowed airways induce an “air hunger” causing a switch to mouth-breathing and an increased respiratory rate leading to hyperinflation. Buteyko believes that this hyperinflation then also contributes to bronchoconstriction. The Buteyko technique aims to reduce ventilation and subsequently lung volume, as a treatment for asthma and other respiratory diseases. A qualified practitioner is necessary to train the patient .
• The Buteyko Technique
  • Breathe normally through the nose for 2-3 mins
  • Breathe out normally, close nose with fingers, and hold
  • Record number of seconds
  • On first need to breathe, release nose and return to nasal breathing (Control Pause)
  • Wait 3 minutes
  • Repeat and hold breath for as long as possible (Maximum Pause)
    

Breathing pattern retraining and relaxed breathing techniques are two approaches to physiotherapy management of asthma. The aim of breathing pattern retraining is to develop a more efficient pattern of respiration, thereby reducing breathlessness. This is usually accomplished by slowing the breathing rate, and encouraging relaxed, ‘abdominal’ breathing (Bruton, 2006). Another potential mechanism for breathing pattern retraining is that by encouraging a longer expiratory time, the effects of any static/ dynamic hyperinflation may be reduced.

Mild asthmatics can hold their breath for up to twenty seconds, moderate asthmatics for fifteen seconds and severe asthmatics for up to ten seconds. The aim of this method is to increase the control pause to 60 seconds and the maximum pause to 2 minutes. It is practiced twice a day, with the practitioner there to help with breath holding and ensure safety. Its aim is to reduce minute volume through reduction of respiratory rate, and increasing carbon dioxide levels through breath holding, reducing bronchospasm caused by hyperventilation in the asthmatic patient.

2. Physical Training

• Physical training with asthma is advised when taking the proper precautions, and should not be avoided. The American College of Sports Medicine (ACSM) Guidelines provide tips and safety precautions for asthmatics to exercise safely.
• Physical training should be prescribed by physiotherapists for asthmatics to increase fitness and cardiorespiratory performance, reduce symptoms such as breathlessness and improve quality of life . Breathlessness, chest tightness and wheezing can occur when exercising, deterring patients from physical exertion . Fear avoidance can contribute to a further deterioration of physical health and quality of life, leading to anxiety and depression. It has been shown that maintaining physical training in asthmatics improves disease symptoms and quality of life, therefore making it a crucial management strategy.
• A study protocol suggests behavior change intervention focussing on increasing participation in physical activity may exert control over asthma and quality of life.
  

3. Respiratory Muscle Training

• Hyperinflation in asthma causes increased lung volume, leading to altered inspiratory muscle mechanics. Inspiratory muscles are shortened resulting in a sub-optimal length-tension relationship for contraction. There is a decreased capacity for tension generation when breathing, resulting in accessory muscles of inspiration being utilised
• Breathing exercises are carried out using an external device to make breathing more difficult. This helps to strengthen the inspiratory muscles, making it easier to breathe in everyday life.
  A breathing device is used which sets up a load to breathe against. During inspiration air is only released if enough effort is used to force open the valves of the device. Respiratory muscles are forced to work harder, increasing their strength, leading to diaphragmatic breathing becoming easier, reducing hyperinflation.
  

4. Removal of secretions

• Percussions
• Shaking
• Vibrations,
• Postural drainage and
• Effective coughing

A randomized crossover study examining the ability of physiotherapy techniques in sputum induction in children and adolescent patients with Asthma suggested that specific physiotherapy maneuvers may facilitate the collection of mucus, yielding the same amount of sputum as the gold-standard technique (hypertonic saline). The study confirms that sputum induction through physiotherapy maneuvers is safe in well-controlled asthmatic, and enables physical therapists to mobilize secretions without causing bronchospasm in patients.

5. Range of motion exercises

• Exercises for patients who need hospitalisation.

6. Education

• About condition
• On use of a bronchodilator and any other medication
• How to prevent chest infection from occurring
• Correct posture in standing and sitting which assists in the management of asthma attacks by allowing the chest to expand appropriately and the lungs to function optimally

Evidenced-Based Physiotherapy Management

Due to the high prevalence of asthma and associated healthcare costs, it is important to identify low-cost alternatives to traditional pharmacotherapy. One of these low-cost alternatives is the use of inspiratory muscle training (IMT), which is a technique aimed at increasing the strength and endurance of the diaphragm and accessory muscles of respiration. IMT typically consists of taking voluntary inspirations against a resistive load across the entire range of vital capacity while at rest. In healthy individuals, the most notable benefits of IMT are an increase in diaphragm thickness and strength, a decrease in exertional dyspnea, and a decrease in the oxygen cost of breathing. IMT has been shown to decrease dyspnea, increase inspiratory muscle strength, and improve exercise capacity in asthmatic individuals.

Also, in a systematic review done by Vera et al. (2012), it was found out that exercise can provoke asthma symptoms, such as dyspnoea, in children with asthma. Exercise-induced bronchoconstriction (EIB) is prevalent in 40–90% of children with asthma. and it was concluded physical exercise is safe and can be recommended in children with asthma. A training programme should have a minimum duration of 3 months, with at least two 60 min training sessions per week, and a training intensity set at the (personalised) ventilatory threshold. Another systematic review by Cristina et al (2018) demonstrated that aerobic physical exercise may improve nocturnal asthma in children and adults by reducing the prevalence and frequency of nocturnal symptoms.  A study protocol will provide the effectiveness of physiotherapy on the quality of life of children with asthma.

Other Health Professional Management

Asthma patients will be involved with a multidisciplinary team to manage their condition. Other health professionals treating the patient include:

• Doctor
  • Initial diagnosis and treatment.
• Consultant
  • Specialised in asthma, to help with reducing symptoms and recognising triggers.
• Specialised Nurse
  • To provide help, education, medication advice and general information.
• Pharmacist
  • Medication distribution.
• Dietitian
  • Advice on proper to diet to not induce symptoms.
• Health Psychologist
  • To help with anxiety/depression associated with symptoms
    

Prevention and Physiotherapist Role In Prevention

Asthma may not be fully preventable due to the pathology progression and the differing possible causes of onset. However, there are ways of avoiding triggers for the disease and reducing symptoms. Being aware of triggers is vital on an individual basis as these will differ amongst sufferers.

Before the onset of disease, a child should avoid causes of asthma such as passive smoking, damp and dusty living environment and allergen exposure, as well as all possible causes for the disease. However, development can be hereditary and may not be preventable.

To prevent asthma attacks, precautions should be made to avoid exacerbations of symptoms and to be aware of the signs of an attack.

• Vaccination against flu and pneumonia
• Learn to recognise warning signs of an attack
• Identify signs of attack and treat early
• Use medication as prescribed
  

A physiotherapist works with the patient to promote a healthy lifestyle benefiting the patient in identifying triggers, reducing symptoms and preventing disease progression. Education, advice and physiotherapy techniques help in the overall outcome of the disease.

Educate on:

• Symptoms
• Breathing Techniques
• Improvement of Quality of Life
  

Advice on:

• Appropriate living environment
• For family members to stop smoking, or not smoke around children
• Promoting a healthy lifestyle, free of air pollution and inhalation irritants
  

Disease Progression:

• Identifying triggers
• Medication management
• Physiotherapy techniques to manage disease
  

Resources

• https://www.mayoclinic.org/diseases-conditions/occupational-asthma/symptoms-causes/syc-20375772
• https://www.pulmonologyadvisor.com/asthma/steroid-resistant-asthma-management-treatment/article/686423/
• https://www.webmd.com/asthma/types-asthma#1
  https://www.ncbi.nlm.nih.gov/pubmed/10849466