Asthma

Question 1

What is asthma?

Answer 1

Commonest chronic condition in childhood

Question 2

What is asthma characterised by?

Answer 2

Reversible and paroxysmal constriction of the airways with airway occlusion, inflammatory exudate and late airway remodelling

Question 3

What proportion of children have asthma in the uk?

Answer 3

1 in 11

Question 4

Describe the pathophysiology of asthma

Answer 4

Multifactorial disease in which susceptible individuals have an exaggerated response to various stimuli
Vast array of mediators that lead to airway obstruction and airway remodelling
TH2 T cell driven
Allergens are presented to these cells by dendritic cells and produce an exaggerated immune response
TH2 cells are activated by dendritic cells and cytokines released from them result in the activation of the humoral immune system with an increased proliferation of mast cells, eosinophils and dendritic cells as a result
Cytokines released contribute to the underlying inflammatory process and bronchoconstriction (C4 - directly toxic to epithelial cells and histamine released from mast cells)

Question 5

List some risk factors for asthma

Answer 5

Genetics - various loci, FH, atopy
Environment - low birth weight, prematurity, parental smoking
Viral bronchiolitis in early life
Atopic dermatitis

Question 6

List some precipitating factors of asthma

Answer 6

Cold air and exercise - drying of the airways due to cold air leads to cell shrinkage and triggers inflammatory response

Atmospheric pollution

Drugs - NSAIDs (shuts down the arachidonic acid pathway towards the production of leukotrienes which are toxic to the epithelium) and Beta blockers (prevent bronchodilatory effect of catecholamines on the airways)

Exposure to allergens

Question 7

Describe the clinical features of asthma

Answer 7

Patterns of wheeze characterised by severity of asthma

• infrequent episodic wheeze - discrete episodes lasting a few days with no interval symptoms
• Frequent episodic wheeze - occurs more frequently than infrequently
• Persistent - wheeze and cough most days and may have disturbed sleep

Question 8

What is preschool wheeze

Answer 8

Common wheeze most children have had at least 1 episode of before 5th birthday

Commonly caused by human rhinovirus or respiratory syncytial virus

Normally preceded by coryzal symptoms

Question 9

Name and describe the 2 clinical patterns of preschool wheeze

Answer 9

Episodic viral wheeze - wheezing only in response to viral infection and no interval symptoms

Multiple trigger wheeze - wheeze in response to viral infection but also other triggers such as aeroallergens and exercise

Question 10

What features should be established in an asthma history?

Answer 10

Age of onset
Frequency of symptoms
Severity of symptoms
Previous treatments tried
Hospital admissions - ITU/HDU ventilatory support 
Food allergens
Triggers for symptoms - exercise, cold air, smoke, allergens, pets, damp housing
PMH - viral infection, eczema, hay fever
FH of atopy

Question 11

What may be found on examination of an asthmatic

Answer 11

Chest shape - hyperinflated - poorly controlled asthma
Chest symmetry
Breath sounds
Presence of wheeze
Examination of throat to assess for tonsillar enlargement - infectious cause

Question 12

What investigations should be done in secondary care when investigating asthma

Answer 12

Spirometry - obstructive pattern (FEV1:FVC <70%) - reversal with bronchodilators

PEFR - peak expiratory flow rate

Bronchial provocation tests - histamine or metacholine

Exercise testing

Skin prick testing or serum specific IgE assays to allergens

Exhaled nitric oxide - nitric oxide produced in bronchial epithelial cells and production increased in those with Th2 driven eosinophilic inflammation

CXR

Oesophageal pH study - GORD

Broncoscopy to exclude structural abnormality - can collect tissue for biopsy or fluid

Chloride sweat tests for CF

Nasal brush biopsy for ciliary evaluation to exclude primary ciliary dyskinesia

Serum IgA, IgG, IgM and response to vaccinations - exclude immunodeficiency

HRCT - exclude bronchiectasis

Sputum culture

Question 13

What is ENO also increased in?

Answer 13

Allergic rhinitis

Question 14

How is asthma managed?

Answer 14

British thoracic society guidelines

Step 1 - Short acting beta 2 agonist - salbutamol as required

Step 2 - Plus inhaled corticosteroid

Step 3 - initial add on - Long acting beta 2 agonist plus ICS, then increase ICS dose and if no response then stop the LABA and switch to a leukotriene receptor antagonist (Montelukast)
Step 4 - persistent poor control - increase dose of ICS
Step 5 - regular oral steroids - referral to resp paediatrician - biological agents

Question 15

Name a monoclonal antibody used to treat asthma

Answer 15

Omalizumab

Question 16

How does Omalizumab work?

Answer 16

Monoclonal antibody for IgE and reduces freee IgE in the blood
Reduces IgE mediated inflammatory response
Should only be given to those with persistent poor control as describe above and evidence of allergic sensation to a perennial aeroallergen and raised serum total IgE

Question 17

What should be used with an aerosol inhaler device?

Answer 17

Spacer

Question 18

When a patient comes in with an exacerbation or symptoms not being controlled which question must you ask?

Answer 18

Compliance

Question 19

What should LABAs be prescribed with?

Answer 19

ICS

Question 20

What is the steroid equivalency of fluticasone compared to beclometasone?

Answer 20

Fluticasone is twice as potent as beclometasone

Question 21

What should all children with asthma have?

Answer 21

A management plan

Question 22

List some complications of asthma

Answer 22

Asthma exacerbation

Question 23

Describe features of a mild asthma attack

Answer 23

SaO2 >92% in air, vocalising without difficulty, mild chest wall recession and moderate tachypnoea

Question 24

Describe features of a moderate asthma attack

Answer 24

SaO2 >92%, breathless, moderate chest wall recession

Question 25

Describe features of a severe asthma attack

Answer 25

SaO2 <92%, PEFR 33-50% best or predicted, cannot complete sentences, HR >125 (>5yo) or >140 (2-5yo)
RR >30 (>5yo) or >40 (2-5yo)

Question 26

Describe features of a life threatening asthma attack

Answer 26

SaO2 <92% 
PEFR <33% predicted 
Silent chest 
Poor respiratory effort
Altered consciousness
Agitation/confusion/exhaustion
Cyanosis

Question 27

What is the immediate management of an asthma exacerbation

Answer 27

O2 - SaO2 <92% should recieve high flow O2 to maintain saturations between 94-98%

Bronchodilators - Inhaled SABA via nebuliser if severe or just inhaler and spacer if moderate/mild

Ipatropium bromide (anti-muscarinic) added if no/poor response to salbutamol

Corticosteroids - short course (3 days) of oral prednisolone however give IV hydrocortisone if too unwell/vomiting

IV salbutamol if inhaled not working

Magnesium sulphate - bronchodilatory effect can also be considered

Question 28

What is required for safe discharge of an asthma exacerbation?

Answer 28

Bronchodilators taken as inhaler device with spacer at intervals of 4 hours or more

SaO2 >94% in air

Inhaler technique assessed/taught

Written asthma management plan given and explained to parents

GP should review child 2 days after discharge