Paediatric Resp Medicine - Asthma Flashcards by Roshan Patel

What is the basic pathophysiology of asthma?

Mast cells are activated
Mast cell degranulation
Release of inflammatory mediators, histamine and prostaglandins

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What does release of histamine cause in the airways?

Smooth muscle contraction
Increased secretions
Increased vascular permeability

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What is asthma?

A chronic reversible inflammatory disorder of the airways associated with airflow obstruction in response to various stimuli

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What risk factors are associated with asthma?

Family history or atopy (hay fever, eczema)
Male sex
Parental smoking

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What is the late phase reaction with regards to asthma?

Occur after initial attack

Eosinophil accumulation cause sustained inflammation

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Who does late phase reaction tend to affect more and how is it treated?

Poorly controlled asthmatics

Treated with steroids

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What environmental factors can precipitate an asthma attack?

Cold and exercise

Atmospheric pollution

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Why does cold and exercise trigger asthma?

Dry out mucosa to make it hyperosmolar which causes mast cells to release cytokines

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What can be protective against asthma attacks?

Fruit and veg - antioxidants

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What symptoms are classical of asthma?

Wheeze
Short of Breath
Chronic cough
Nocturnal symptoms

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What 3 changes happen in asthma which is referred to as “long term remodelling” of the airways?

Bronchial basement membrane thicken

Ciliated columnar epithelium replaced with mucus producing cells

Smooth muscle hypertrophy

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What patterns of asthma are seen in children?

Infrequent episodic
Frequent episodic
Persistent episodic

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How do children with infrequent episodic asthma present?

Normal lung function and examination

Attack triggered by viral URTI’s

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How are children with infrequent episodic asthma managed? What is the prognosis?

Intermittent bronchodilators
Short course of oral steroids for severe exacerbations

40% remain symptomatic in adulthood

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How do children with frequent episodic asthma present?

Abnormal lung function when symptomatic

Severe exacerbations but mild interval symptoms - esp. if exercise induced

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How are children with frequent episodic asthma managed? What is the prognosis?

Inhaled steroids +- add on therapy

70% remain symptomatic in adulthood

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How do children with persistent episodic asthma present?

Daily symptoms and use of bronchodilators

Abnormal lung function

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How are children with persistent episodic asthma managed and what is the prognosis?

Inhaled steroids + add on therapy

90% remain symptomatic in adulthood

When auscultating a child with asthma between attacks, what are you likely to hear?

Normal lung function

What thoracic deformity is associated with chronic asthma?

Hyperexpansion
Pectus carinatum (pigeon chest)
Harrison sulcus

What investigations would you do if you suspect asthma? What result would indicate asthma?

1 Spirometry - FEV1/FVC <70%
2 Bronchodilator reversibility - FEV1 improve >12%
3 Fractional exhaled - NO >35ppb
4 Peak flow monitoring for 2-4 weeks - >20% variability

Move down if previous investigation uncertain

CXR can be useful

What differential diagnoses would you consider for asthma?

CF
GORD
Central airways disease
Laryngeal problems
Inhaled foreign body
Postviral wheeze

At what age are investigations carried out?

Child >5yo

How common is asthma in children?

1 in 11 children in the UK

What drugs can precipitate an asthma attack?

NSAID's - shunt arachidonic acid pathway towards producing leukotrienes - toxic to epithelium Beta blockers - prevent bronchodilatory effect of catecholamines on airways

What features do you want to ask about in an asthma history?

``` Age of onset of symptoms Frequency of symptoms Severity of symptoms Previous treatment Hospital attendance? Food allergies? Triggers? Disease history Family/PMH - atopy ```

What should you look for on examination of a child with asthma?

Clubbing - more suggestive of CF or bronchiectasis Chest shape + symmetry Breath sounds Crepitations Wheeze Throat assessment - tonsillar enlargement

What is the aim of asthma treatment?

``` No daytime symptoms or waking at night No exacerbations No need for reliever No limitations on activity Normal lung function Minimal side effects ```

What is important when trying to meet the aims of asthma treatment?

``` Patient education Establish minimum effective dose Age appropriate delivery device Accurate diagnosis and assessment of severity - review Avoid triggers ```

How is asthma managed in under 5's?

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.

When should maintenance dose be increased?

>3 days a week of symptoms | 1 night a week of waking

When should maintenance be decreased?

3 months controlled

How is asthma managed for 5-12 yo?

``` 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. ```

With what should aerosol inhaler devices be used?

With a spacer device

What must you do when reviewing a child's asthma control?

Check compliance | Check inhaler technique

What is the relative strength of fluticasone compared to beclometasone?

Fluticasone is twice as potent

How can asthma attacks be categorised?

Mild Moderate Severe Life threatening

With what obs would a patient having a mild/moderate asthma attack present?

``` Sats >92% RR age 2-5: <40 RR age >5: <30 HR age 2-5: <140 HR age >5: <125 Able to complete sentences Wheeze PEFR >75% (mild) 50-75% (moderate) ```

How would a child having a severe asthma attack present

``` Sats <92% RR age 2-5: >40 RR age >5: >30 HR age 2-5: >140 HR age >5: >125 No sentences No wheeze PEFR 35-50% ```

How would a child having a life threatening asthma attack present?

``` Cyanosed No respiratory effort Confused Hypotensive Comatosed Silent chest PEFR <35% ```

How are asthma attacks managed immediately?

Sats <94% - high flow O2 to keep sats between 94-98% Nebulised salbutamol back to back with ipratropium bromide nebuliser Oral prednisolone ABG, record PEF, check sats, CXR - exclude pneumothorax

What is second line management for an asthma attack?

``` IV Salbutamol (with specialist input) IV Magnesium sulphate IV salbutamol IV aminophyline ```

What is the criteria for safe discharge following an asthma attack?

``` Bronchodilators 4 hourly Sats >94% in air Inhaler technique assessed Written asthma management plan explained to parents GP review within 2 days ```