Paediatric Resp Medicine - Asthma Flashcards
What is the basic pathophysiology of asthma?
Mast cells are activated
Mast cell degranulation
Release of inflammatory mediators, histamine and prostaglandins
What does release of histamine cause in the airways?
Smooth muscle contraction
Increased secretions
Increased vascular permeability
What is asthma?
A chronic reversible inflammatory disorder of the airways associated with airflow obstruction in response to various stimuli
What risk factors are associated with asthma?
Family history or atopy (hay fever, eczema)
Male sex
Parental smoking
What is the late phase reaction with regards to asthma?
Occur after initial attack
Eosinophil accumulation cause sustained inflammation
Who does late phase reaction tend to affect more and how is it treated?
Poorly controlled asthmatics
Treated with steroids
What environmental factors can precipitate an asthma attack?
Cold and exercise
Atmospheric pollution
Why does cold and exercise trigger asthma?
Dry out mucosa to make it hyperosmolar which causes mast cells to release cytokines
What can be protective against asthma attacks?
Fruit and veg - antioxidants
What symptoms are classical of asthma?
Wheeze
Short of Breath
Chronic cough
Nocturnal symptoms
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
What patterns of asthma are seen in children?
Infrequent episodic
Frequent episodic
Persistent episodic
How do children with infrequent episodic asthma present?
Normal lung function and examination
Attack triggered by viral URTI’s
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
How do children with frequent episodic asthma present?
Abnormal lung function when symptomatic
Severe exacerbations but mild interval symptoms - esp. if exercise induced
How are children with frequent episodic asthma managed? What is the prognosis?
Inhaled steroids +- add on therapy
70% remain symptomatic in adulthood
How do children with persistent episodic asthma present?
Daily symptoms and use of bronchodilators
Abnormal lung function
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?
- Start a short-acting beta-2 agonist inhaler (e.g. salbutamol) as required
- Add a low dose corticosteroid inhaler or a leukotriene antagonist (i.e. oral montelukast)
- Add the other option from step 2.
- 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
