Chronic Asthma

Asthma is a chronic inflammatory airway disease leading to variable airway obstruction. The smooth muscle in the airways is hypersensitive, and responds to stimuli by constricting and causing airflow obstruction. This bronchoconstriction is reversible with bronchodilators such as inhaled salbutamol.

Asthma is one of a number of atopic conditions, which include asthma, eczema, hay fever and food allergies. Patients with one of these conditions are more likely to have others. These conditions characteristically run in families, so always ask about family history and don’t be surprised if their brother, mother or “everyone in the family” has asthma, eczema and allergies.

 

Presentation Suggesting a Diagnosis of Asthma

  • Episodic symptoms with intermittent exacerbations
  • Diurnal variability, typically worse at night and early morning
  • Dry cough with wheeze and shortness of breath
  • Typical triggers
  • A history of other atopic conditions such as eczema, hayfever and food allergies
  • Family history of asthma or atopy
  • Bilateral widespread “polyphonic” wheeze heard by a healthcare professional
  • Symptoms improve with bronchodilators

 

Presentation Indicating a Diagnosis Other Than Asthma

  • Wheeze only related to coughs and colds, more suggestive of viral induced wheeze
  • Isolated or productive cough
  • Normal investigations
  • No response to treatment
  • Unilateral wheeze suggesting a focal lesion, inhaled foreign body or infection

 

Typical Triggers

  • Dust (house dust mites)
  • Animals
  • Cold air
  • Exercise
  • Smoke
  • Food allergens (e.g. peanuts, shellfish or eggs)

 

Diagnosis of Asthma

There is no gold standard test or diagnostic criteria for asthma. A diagnosis is made clinically based on a typical history and examination. Children are usually not diagnosed with asthma until they are at least 2 to 3 years old. When there is a low probability of asthma and the child is symptomatic, consider referral to a specialist for diagnosis.

When there is an intermediate or high probability of asthma, a trial of treatment can be implemented and if the treatment improves symptoms a diagnosis can be made.

There are investigations that can be used where there is an intermediate probability of asthma or diagnostic doubt:

  • Spirometry with reversibility testing (in children aged over 5 years)
  • Direct bronchial challenge test with histamine or methacholine
  • Fractional exhaled nitric oxide (FeNO)
  • Peak flow variability measured by keeping a diary of peak flow measurements several times a day for 2 to 4 weeks

 

Long Term Management

The treatment here is based on the 2016 BTS/SIGN guidelines. It is a summary to help your understanding and learning and it is essential that you consult guidelines and seniors before treating patients. 

The principles of using the stepwise ladder are to:

  • Start at the most appropriate step for the severity of the symptoms
  • Review at regular intervals based on the severity
  • Step up and down the ladder based on symptoms
  • Aim to achieve no symptoms or exacerbations on the lowest dose and number of treatments
  • Always check inhaler technique and adherence at each review

 

Medical Therapy in Under 5 Years

  1. Start a short-acting beta-2 agonist inhaler (e.g. salbutamol) as required
  2. Add a low dose corticosteroid inhaler or a leukotriene antagonist (i.e. oral montelukast)
  3. Add the other option from step 2.
  4. Refer to a specialist.

 

Medical Therapy Aged 5 – 12 Years

  1. Start a short-acting beta-2 agonist inhaler (e.g. salbutamol) as required
  2. Add a regular low dose corticosteroid inhaler
  3. Add a long-acting beta-2 agonist inhaler (e.g. salmeterol). Continue salmeterol only if the patient has a good response.
  4. Titrate up the corticosteroid inhaler to a medium dose. Consider adding:
    • Oral leukotriene receptor antagonist (e.g. montelukast)
    • Oral theophylline
  5. Increase the dose of the inhaled corticosteroid to a high dose.
  6. Referral to a specialist. They may require daily oral steroids.

 

Medical Therapy Aged Over 12 Years (Same as Adults)

  1. Start a short-acting beta 2 agonist inhaler (e.g. salbutamol) as required
  2. Add a regular low dose corticosteroid inhaler
  3. Add a long-acting beta-2 agonist inhaler (e.g. salmeterol). Continue salmeterol only if the patient has a good response.
  4. Titrate up the corticosteroid inhaler to a medium dose. Consider a trial of an oral leukotriene receptor antagonist (i.e. montelukast), oral theophylline or an inhaled LAMA (i.e. tiotropium).
  5. Titrate the inhaled corticosteroid up to a high dose. Combine additional treatments from step 4, including the option of an oral beta 2 agonist (i.e. oral salbutamol). Refer to specialist.
  6. Add oral steroids at the lowest dose possible to achieve good control under specialist guidance.

 

Inhaled Corticosteroids in Children

A potential exam scenario is discussing inhaled steroids with a parent that is worried about potential side effects. A common question is whether they slow growth. There is evidence that inhaled steroids can slightly reduce growth velocity and can cause a small reduction in final adult height of up to 1cm when used long term (for more than 12 months). This effect was dose-dependent, meaning it was less of a problem with smaller doses.

It is worth putting this in context for the parent by explaining that these are effective medications that work to prevent poorly controlled asthma and asthma attacks that could lead to higher doses of oral steroids being given. Poorly controlled asthma can lead to a more significant impact on growth and development. The child will also have regular asthma reviews to ensure they are growing well and on the minimal dose required to effectively control symptoms.

 

Inhaler Technique

Inhaler technique is a key aspect of good asthma management. The better the technique, the more medication reaches the lungs. Poor technique results in medication in the mouth or the back of the throat. This reduces the effectiveness of the medication and leads to complications such as oral thrush with steroid inhalers.

Ideally, inhalers should be used with a spacer device to maximise their effectiveness. There are multiple types of inhaler with different techniques. This focuses on the technique used for the typical salbutamol metered dosed inhaler (MDI). There are also dry powder inhalers that require the patient to inhale quickly and deeply to draw the powder into the lungs.

 

MDI technique without a spacer:

  • Remove the cap
  • Shake the inhaler (depending on the type)
  • Sit or stand up straight
  • Lift the chin slightly
  • Fully exhale
  • Make a tight seal around the inhaler between the lips
  • Take a steady breath in whilst pressing the canister
  • Continue breathing for 3 – 4 seconds after pressing the canister
  • Hold the breath for 10 seconds or as long as comfortably possible
  • Wait 30 seconds before giving a further dose
  • Rinse the mouth after using a steroid inhaler

 

MDI technique with a spacer:

  • Assemble the spacer
  • Shake the inhaler (depending on the type)
  • Attach the inhaler to the correct end
  • Sit or stand up straight
  • Lift the chin slightly
  • Make a seal around the spacer mouthpiece or place the mask over the face
  • Spray the dose into the spacer
  • Take steady breaths in and out 5 times until the mist is fully inhaled

Alternatively exhale fully before putting making a seal with the spacer, spray the dose and take one deep breath in to inhale the mist in one breath before holding for 10 seconds.

Spacers should be cleaned once a month. Avoid scrubbing the inside and allow them to air dry to avoid creating static. Static can interact with the mist and prevent the medication being inhaled.

TOM TIP: Teaching inhaler technique is a common exam task, so practice with colleagues. It is important to check inhaler technique during asthma review. If you come across a poorly controlled asthmatic who states they are taking their inhalers as prescribed, consider whether their inhaler technique is adequate, as this may be the cause of their poor asthma control.

 

Last updated August 2019
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