Respiratory: Acute & Chronic Asthma in Children

Question 1

What is the most common chronic condition in children?

Answer 1

Asthma

Question 2

What is asthma?

Answer 2

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.

Question 3

Risk factors for childhood asthma?

Answer 3

1) FH

2) Males (however, this gender predominance tends to even out once in adulthood)

3) Poor maternal asthma control

4) Maternal smoking

5) Prematurity

6) Exposure to allergens e.g. dust mites, fungi, animal proteins

7) Respiratory infections in early life e.g. viral bronchiolitis

8) Exposure to passive smoking

Question 4

A key feature of asthma is that the airflow limitation is variable and reversible.

The airflow obstruction is as a result of what three factors?

Answer 4

1) smooth muscle contraction

2) mucous production

3) bronchial inflammation

Question 5

Typical symptoms of asthma?

Answer 5

1) Cough
- diurnal variability (worse at night and early morning)
- lasting >3 weeks
- can be triggered by seasons or allergens
- dry and non-productive

2) SOB
- occurs usually on exertion or on exposure to triggers (e.g. cold air, tobacco smoke, crying, exercise)
- may accompany wheeze and cough during an exacerbation

Question 6

Signs seen in asthma?

Answer 6

1) Wheeze
- typically expiratory
- polyphonic (variable pitch)

2) Silent chest (emergency)

3) Increased work of breathing:
- tachypnoea
- use of accessory muscles of respiration
- nasal flaring
- sitting in forward posture

Question 7

What are some precipitating factors for an exacerbation of asthma?

Answer 7

1) Cold air and exercise

2) Atmospheric pollution

3) Drugs: NSAIDs, beta blockers

4) Exposure to allergens

Question 8

How can cold air & exercise precipitate an asthma attack?

Answer 8

Drying of the airways due to cold air and exercise leads to cell shrinkage, which triggers an inflammatory response.

Question 9

What 2 drugs can precipitate an asthma exacerbation?

Answer 9

1) NSAIDs

2) Beta blockers

Question 10

How can beta blockers precipitate an asthma attack?

Answer 10

Beta-blockers prevent the bronchodilatory effect of catecholamines on the airways

Question 11

How can NSAIDs precipitate an asthma attack?

Answer 11

NSAIDs shunt the arachadonic acid pathway towards the production of leukotrienes, which are toxic to the epithelium.

Question 12

What important features must be established when taking an asthma history for a child?

Answer 12

1) Age at onset of symptoms

2) Frequency of symptoms

3) Severity of symptoms (how many days of school missed? Can the child do PE at school? Can they play with their friends without getting symptoms? Night time symptoms?)

4) Previous treatments tried

5) Any hospital attendances (A+E or admissions – including HDU/ITU admission – ventilated?

6) Presence of food allergies

7) Triggers for symptoms: Exercise, cold air, smoke, allergens, pets, damp housing

8) Disease history: Viral infections, eczema, hay fever

9) Family history of atopy

Question 13

What are some presenting features that indicate a diagnosing OTHER THAN asthma?

Answer 13

1) Wheeze only related to coughs and colds –> more suggestive of viral induced wheeze

2) Isolated or productive cough

3) Normal investigations

4) No response to treatment

5) Unilateral wheeze suggesting a focal lesion, inhaled foreign body or infection

Question 14

What signs may indicate a severe asthma exacerbation?

Answer 14

1) Altered mental state (e.g. confusion, drowsiness)

2) Maximal work of breathing accessory muscle use/recession

3) Exhaustion

4) Significant tachycardia

5) Unable to talk

6) Silent chest (note: wheeze is typically a poor predictor of severity)

Question 15

What investigations may be useful for the diagnosis of asthma?

N.B. In primary care, investigations are rarely performed; asthma is a clinical diagnosis and has no single diagnostic test.

Answer 15

1) Spirometry with reversibility testing (in children aged over 5 years)

2) Peak expiratory flow rate (PEFR) and variability (keep diary)

3) FeNO

4) Direct bronchial challenge test with histamine or methacholine

Question 16

What is used for a direct bronchial challenge test in asthma?

Answer 16

Histamine or methacholine

Question 17

When should spirometry be offered to children with asthma?

Answer 17

> 5 years old

Question 18

What FEV1:FVC ratio indicate obstructive airway disease?

Answer 18

<70%

Question 19

What is spirometry with bronchodilator reversibility?

Answer 19

To be classified as asthma, obstructive airway disease needs to show an element of reversibility, and therefore testing with bronchodilators is necessary.

For children aged 5 to 16-years-old, an improvement in FEV1 of >12% is suggestive of asthma.

For children aged 17 years-old and older, an improvement in FEV1 of >12%, plus an increase in volume of >200mL, is suggestive of asthma.

Question 20

What FEV1 improvement following bronchodilator therapy indicates asthma?

Answer 20

improvement in FEV1 of >12%

Question 21

What is the key differential for childhood asthma?

Answer 21

Viral induced wheeze

Question 22

Management of childhood asthma?

Answer 22

The overarching aim of managing asthma is to achieve good symptom control.WH

Question 23

What does ‘good symptom control’ mean in childhood asthma?

Answer 23

1) full school attendance

2) no sleep disturbance

3) <2/week daytime symptoms

4) no limitation on daily activities

5) no exacerbations

6) using salbutamol <2/week

7) maintaining normal lung function.

Question 24

Stepwise management of asthma in children <5?

Answer 24

1) SABA (salbutamol) as required

2) + inhaled corticosteroids (8 week trial)

3) SABA + ICS + leukotriene receptor antagonist (LTRA)

4) Stop LTRA and refer the child to a specialist

Question 25

What would indicate the need for the addition of an ICS in asthma in children <5?

Answer 25

Not controlled on previous step

OR

Newly-diagnosed asthma with symptoms >= 3 / week or night-time waking

Question 26

What are the next steps following the 8 week ICS trial period for asthma in children <5?

Answer 26

1) if symptoms did not resolve during the trial period –> review whether an alternative diagnosis is likely

2) if symptoms resolved then reoccurred WITHIN 4 weeks of stopping ICS treatment –> restart the ICS at a paediatric low dose as first-line maintenance therapy

3) if symptoms resolved but reoccurred AFTER 4 weeks after stopping ICS treatment –> repeat the 8‑week trial of a paediatric moderate dose of ICS

Question 27

Stepwise management of asthma in children aged 5-16?

Answer 27

1) SABA

2) SABA + low dose ICS

3) SABA + low dose ICS + LTRA

4) Stop LTRA and start LABA

5) Switch ICS/LABA for a MART regimen that includes a paediatric low-dose ICS

6) Increase ICS dose (either continuing on a MART regimen or changing to a fixed dose of an ICS and a LABA, with a SABA)

7) Seek specialist advice

Question 28

What should long-acting beta-2 agonists (e.g. salmeterol) always be prescribed with?

Answer 28

should be prescribed in combination with a corticosteroid.

Question 29

Stepwise management of asthma in adults (≥17)?

Answer 29

1) SABA

2) SABA + ICS

3) SABA + ICS + LTRA

4) SABA + ICS + LABA (discuss with the person whether or not to continue LTRA treatment)

5) Cahnge to ICS and LABA MART regimen with a low dose ICS

6) Consider increasing ICS to a moderate dose ((either continuing on a MART regimen or changing to a fixed dose of an ICS and a LABA, with a SABA as a reliever therapy)

7) Options:
- increase ICS to high maintenance dose (part of MART)
- a trial of an additional drug (for example, a long-acting muscarinic receptor antagonist or theophylline)
- seek specialist advice

Question 30

What is aintenance and reliever therapy (MART)?

Answer 30

A form of combined ICS and LABA treatment in which a single inhaler, containing both ICS and a fast-acting LABA, is used for both daily maintenance therapy and the relief of symptoms as required.

Question 31

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.

What is some information about this?

Answer 31

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.

Question 32

SpO2 in mild/mod, severe & life threatening asthma attack?

Answer 32

Mild/mod: >92%

Severe: <92%

Life threatening: <92%

Question 33

RR in mild/mod, severe & life threatening asthma attack?

Answer 33

Mild/mod:
- <30 (over 5’s)
- <40 (under 5’s)

Severe:
- >30 (over 5’s)
- >40 (under 5’s)

Life threatening:
- poor respiratory effort

Question 34

PEFR in severe vs life threatening asthma attack?

Answer 34

Severe: PEFR 33-50% predicted

Life threatening: PEFR <33% predicted

Question 35

Signs of a life threatening asthma attack?

Answer 35

1) SpO2 <92%

2) PEFR <33% predicted

3) Silent chest

4) Poor respiratory effort

5) Altered consciousness

6) Agitation/confusion

7) Exhaustion

8) Cyanosis

Question 36

Ideally, what should asthma inhalers be used with to maximise their effectiveness?

Answer 36

A spacer device

Question 37

Give a stepwise approach to technique for the typical salbutamol metered dosed inhaler (MDI)?

Answer 37

1) Remove the cap

2) Shake the inhaler (depending on the type)

3) Sit or stand up straight

4) Lift the chin slightly

5) Fully exhale

6) Make a tight seal around the inhaler between the lips

7) Take a steady breath in whilst pressing the canister

8) Continue breathing for 3 – 4 seconds after pressing the canister

9) Hold the breath for 10 seconds or as long as comfortably possible

10) Wait 30 seconds before giving a further dose

11) Rinse the mouth after using a steroid inhaler

Question 38

If you come across a poorly controlled asthmatic who states they are taking their inhalers as prescribed, what should you ask?

Answer 38

Consider whether their inhaler technique is adequate, as this may be the cause of their poor asthma control.

Question 39

Management of asthma attack?

Answer 39

1st line:

1) O2: if sats <94%

2) Nebulised SABA (salbutamol)

3) Ipatropium bromide (anti-muscuranic) added in if no or poor response to inhaled SABA

4) Corticosteroids (3 day course)
- oral prednisolone (1st line)
- IV hydrocortisone (if oral route contraindicated e.g. vomiting)

2nd line (with specialist input):

5) IV salbutamol: if there is no response to inhaled bronchodilators

6) IV magnesium sulphate

7) IV aminophylline

8) Intubation & ventilation

Question 40

Safe discharge criteria following an asthma attack in a child?

Answer 40

1) Bronchodilators are taken as inhaler device with spacer at intervals of 4-hourly or more (e.g. 6 puffs salbutamol via spacer every 4 hours)

2) SaO2 >94% in air

3) Inhaler technique assessed/taught

4) Written asthma management plan given and explained to parents

5) GP should review the child 2 days after discharge

Question 41

What is a viral induced wheeze?

Answer 41

An acute wheezy illness caused by a viral infection.

Question 42

Pathophysiology in a viral induced wheeze?

Answer 42

Small children (typically under 3 years) have small airways.

When these small airways encounter a virus (commonly RSV or rhinovirus) they develop a small amount of inflammation and oedema, swelling the walls of the airways and restricting the space for air to flow.

This inflammation also triggers the smooth muscles of the airways to constrict, further narrowing the space in the airway.

Due to the small diameter of a child’s airway, the slight narrowing leads to a proportionally larger restriction in airflow.

Question 43

What is Poiseuille’s law?

Answer 43

States that the flow rate is proportional to the radius of the tube to the power of four.

Therefore, halving the diameter of the tube decreases flow rate by 16 fold.

Question 44

Wheeze is extremely common in pre-school children.

What % of children have an episode of wheeze before 18 months?

Answer 44

25%

Question 45

Pre-school wheeze can be separated into what 2 categories?

Answer 45

1) Episodic viral wheeze

2) Multiple trigger wheeze

Question 46

What is episodic viral wheeze?

Answer 46

Child only wheezes when has a viral upper respiratory tract infection (URTI) and is symptom free inbetween episodes.

Question 47

What is multiple trigger wheeze?

Answer 47

As well as viral URTIs, other factors appear to trigger the wheeze such as exercise, allergens and cigarette smoke

Question 48

Is episodic viral wheeze associated with an increased risk of asthma?

Answer 48

No

Question 49

Is multiple trigger wheeze associated with an increased risk of asthma?

Answer 49

Yes

Question 50

Generally, what features can differentiate between a viral induced wheeze and asthma?

Answer 50

Generally, typical features of viral-induced wheeze (as opposed to asthma) are:

1) Presenting before 3 years of age
2) No atopic history
3) Only occurs during viral infections

Question 51

Presentation of a viral induced wheeze?

Answer 51

Evidence of a viral illness (fever, cough and coryzal symptoms) for 1-2 days preceding the onset of:

1) Shortness of breath
2) Signs of respiratory distress
3) Expiratory wheeze throughout the chest

Question 52

Does a viral-induced wheeze cause a focal wheeze?

Answer 52

Neither viral-induced wheeze or asthma cause a focal wheeze. If you hear a focal wheeze be very cautious and investigate further for a focal airway obstruction such as an inhaled foreign body or tumour. These patients will require an urgent senior review.

Question 53

Management of viral induced wheeze?

Answer 53

Treatment is symptomatic only

1st line –> short acting beta 2 agonists (e.g. salbutamol) or anticholinergic via a spacer

2nd line –> intermittent leukotriene receptor antagonist (montelukast), intermittent inhaled corticosteroids, or both

There is now thought to be little role for oral prednisolone in children who do not require hospital treatment.

Question 54

What lifestyle advice should be given to parents regarding pre-school wheeze?

Answer 54

Parents who are smokers should be strongly encouraged to stop.

Question 55

1st line management of viral induced wheeze?

Answer 55

SABA e.g. salbutamol or anticholinergic via a spacer

Question 56

2nd line management of viral induced wheeze (after SABA)?

Answer 56

Intermittent leukotriene receptor antagonist (montelukast), intermittent inhaled corticosteroids, or both.

Question 57

Management of multiple trigger wheeze?

Answer 57

Trial of either inhaled corticosteroids or a leukotriene receptor antagonist (montelukast), typically for 4-8 weeks.