Asthma

Question 1

Define asthma.

Answer 1

Episodic, reversible intrathoracic airway obstruction, airway hyper-responsiveness +bronchial inflammation.

Question 2

Define viral induced wheeze.

Answer 2

Small airways more likely to narrow + obstruct with inflammation + aberrant immune response to viral infection

Episodic

Age 1-5

Question 3

What are the risk factors for asthma?

Answer 3

FH of asthma/ atopy.

Question 4

What is the pathogenesis of asthma?

Answer 4

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.

Question 5

Summarise the epidemiology of asthma.

Answer 5

10–15% children

80% of asthmatic children are symptomatic by age 5.

M: F 2:1

Higher in urban areas + low socio-economic status

Question 6

What are the presenting symptoms of asthma?

Answer 6

End-expiratory polyphonic wheeze

SOB

Non-productive cough

Chest tightness

Sx worse at night + in morning

Question 7

What are 4 signs of asthma?

Answer 7

End-expiratory polyphonic wheeze

Intercostal/ subcostal recessions

Hyperinflated chest + accessory muscle use

Harrison sulcus (anterolateral depression of thorax at insertion of diaphragm).

Question 8

How is asthma diagnosed in under 5s?

Answer 8

Clinical dx

Question 9

What are the features of a moderate asthma attack?

Answer 9

PEFR >50%

Speech normal

RR <40/min in <5s, <30 in >5s

HR <140 in <5s, <125 in >5s

Question 10

What are the features of a severe asthma attack?

Answer 10

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

Question 11

What are the features of a life-threatening asthma attack?

Answer 11

PEFR <33% best or predicted

Oxygen sats <92%

Silent chest, cyanosis or poor respitatory effort

Cardiac arrhythmia +/- hypotension

Exhaustion/ confusion

Question 12

How should an acute asthma attack in a child be managed?

Answer 12

HIGH flow O2

1. 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

2. IV BOLUS: give MgSO4 (or salbutamol/ aminophylline)
3. IV INFUSION: IV salbutamol/ aminophylline
4. PANIC: Intubate + ventillate

Question 13

What additional drug may be given in the burst step in an asthma attack, though not in general hypoxia?

Answer 13

Oral prednisolone

Question 14

After stabilising a patient in an acute asthma attack, describe management

Answer 14

Give salbutamol 1 hourly- 2 hourly- 3 hourly- 4 hourly

Discharge when stable on 4 hourly tx, peak flow at 75% + SpO2 >94%

Question 15

Recall outpatient management of asthma in children over 5

Answer 15

1. SABA
2. SABA + ICS
3. SABA + ICS + LTRA
4. SABA + ICS + LABA
5. SABA + low dose ICS MART
6. SABA + mod dose ICS MART / mod ICS + LABA
7. • increase ICS to paediatric high dose / Theophylline

Question 16

Recall 4 contraindications of beta-agonists/ salbutamol

Answer 16

Beta-blockers
NSAIDs
Adenosine
ACE inhibitors

Question 17

What must be discussed on discharge post asthma attack?

Answer 17

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)

Question 18

What is maintenance and reliever therapy (MART)?

Answer 18

A single inhaler, containing both ICS + a fast-acting LABA, used for both daily maintenance therapy.

MART: Formoterol- ICS + fast-acting LABA

Question 19

What are the different doses for corticosteroids?

Answer 19

• Low dose: <200 mcg
• Moderate dose: 200-400 mcg
• High dose: >400 mcg

Question 20

What is the management for a viral induced wheeze?

Answer 20

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.

Question 21

What are the complications associated with asthma?

Answer 21

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.

Question 22

What is the prognosis of asthma?

Answer 22

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.

Question 23

List 6 environmental triggers for asthma

Answer 23

Passive smoking

URTIs

Exercise

Cold weather

Inhalant allergies (house dust mite/pollens/moulds/pets)

Food allergens.

Question 24

When are Peak flow meters used in childhood asthma?

Answer 24

>5 years of age; use as baseline (predicted best) + as determinant for efficacy of tx.

Question 25

How is suspected asthma investigated in >5s?

Answer 25

Vital signs: BP, HR, RR, SpO2, temp

PEFR variability + diary

Spirometry- FEV1: FVC <70%

Bronchodilator 12% pre/ post difference