Asthma Flashcards
Define asthma.
Episodic, reversible intrathoracic airway obstruction, airway hyper-responsiveness +bronchial inflammation.
Define viral induced wheeze.
Small airways more likely to narrow + obstruct with inflammation + aberrant immune response to viral infection
Episodic
Age 1-5
What are the risk factors for asthma?
FH of asthma/ atopy.
What is the pathogenesis of asthma?
Acute phase (within minutes): Contact with exacerbating factor (cigarette smoke, inhalant or food allergen or viral infection) leads to airway receptor hyper-responsiveness and narrowing of airways.
L_ate phase (onset after 2–4 hours, effect may last up to 3–6 months):_ Persistent bronchoconstriction secondary to vicious cycle of inflammation, oedema and excess mucous production.
Summarise the epidemiology of asthma.
10–15% children
80% of asthmatic children are symptomatic by age 5.
M: F 2:1
Higher in urban areas + low socio-economic status
What are the presenting symptoms of asthma?
End-expiratory polyphonic wheeze
SOB
Non-productive cough
Chest tightness
Sx worse at night + in morning
What are 4 signs of asthma?
End-expiratory polyphonic wheeze
Intercostal/ subcostal recessions
Hyperinflated chest + accessory muscle use
Harrison sulcus (anterolateral depression of thorax at insertion of diaphragm).
How is asthma diagnosed in under 5s?
Clinical dx
What are the features of a moderate asthma attack?
PEFR >50%
Speech normal
RR <40/min in <5s, <30 in >5s
HR <140 in <5s, <125 in >5s
What are the features of a severe asthma attack?
PEFR 33-50% best or predicted
Can’t complete sentences
RR >40/min in <5s, >30 in >5s
HR >140bpm in <5s, >125 in >5s
What are the features of a life-threatening asthma attack?
PEFR <33% best or predicted
Oxygen sats <92%
Silent chest, cyanosis or poor respitatory effort
Cardiac arrhythmia +/- hypotension
Exhaustion/ confusion
How should an acute asthma attack in a child be managed?
HIGH flow O2
- BURST
3x salbutamol nebs, or up to 10 inhales on a pump (SE: tremor, vomiting)
2x ipratropium bromide nebs
Involve seniors if burst therapy has failed to work
- IV BOLUS: give MgSO4 (or salbutamol/ aminophylline)
- IV INFUSION: IV salbutamol/ aminophylline
- PANIC: Intubate + ventillate
What additional drug may be given in the burst step in an asthma attack, though not in general hypoxia?
Oral prednisolone
After stabilising a patient in an acute asthma attack, describe management
Give salbutamol 1 hourly- 2 hourly- 3 hourly- 4 hourly
Discharge when stable on 4 hourly tx, peak flow at 75% + SpO2 >94%
Recall outpatient management of asthma in children over 5
- SABA
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS + LABA
- SABA + low dose ICS MART
- SABA + mod dose ICS MART / mod ICS + LABA
- increase ICS to paediatric high dose / Theophylline
Recall 4 contraindications of beta-agonists/ salbutamol
Beta-blockers
NSAIDs
Adenosine
ACE inhibitors
What must be discussed on discharge post asthma attack?
When drugs should be used (regularly or PRN; frequency + dosage)
How to use the drug (inhaler technique)
What each drug does (relief vs prevention)
What to do if asthma worsens (personalised asthma management action plan)
What is maintenance and reliever therapy (MART)?
A single inhaler, containing both ICS + a fast-acting LABA, used for both daily maintenance therapy.
MART: Formoterol- ICS + fast-acting LABA
What are the different doses for corticosteroids?
- Low dose: <200 mcg
- Moderate dose: 200-400 mcg
- High dose: >400 mcg
What is the management for a viral induced wheeze?
Episodic: Montelukast 1st line, started at 1st sign of viral cold.
Multi-trigger: Inhaled corticosteroids or Montelukast trial for 4-8 weeks. If Sx reoccur reduce tx to lowest level but may have to consider asthma dx.
Can use inhaled bronchodilator. Need to confirm dx of asthma before using oral steroids.
What are the complications associated with asthma?
Decreased linear growth rate due to poorly controlled asthma more usual than from over prescription of inhaled steroids, chest wall deformity, recurrent infections, status asthmaticus can be fatal.
One-third of deaths occur under the age of 5 years.
What is the prognosis of asthma?
Asthma often remits during puberty and many children are symptom free as adults, especially those who have mild asthma and are asymptomatic between attacks, or who develop asthma at >6 years. Rates of admission and mortality in asthma have decreased since the early 1990s.
List 6 environmental triggers for asthma
Passive smoking
URTIs
Exercise
Cold weather
Inhalant allergies (house dust mite/pollens/moulds/pets)
Food allergens.
When are Peak flow meters used in childhood asthma?
>5 years of age; use as baseline (predicted best) + as determinant for efficacy of tx.
How is suspected asthma investigated in >5s?
Vital signs: BP, HR, RR, SpO2, temp
PEFR variability + diary
Spirometry- FEV1: FVC <70%
Bronchodilator 12% pre/ post difference
