Asthma

Question 1

What is asthma?

Answer 1

Chronic inflammatory disease of airways
Airway obstruction that is reversible
Increased airway responsiveness to stimuli

Question 2

What are some differentials for a wheeze?

Answer 2

-Acute asthma exacerbation
-bronchitis
-pulmonary oedema
-GORD
-allergy
-vocal cord dysfunction

Question 3

What are some typical symptoms of asthma?

Answer 3

Shortness of breath
Chest tightness
Dry cough
Wheeze

Question 4

What are some typical asthma triggers?

Answer 4

Infection
Nighttime or early morning
Exercise
Animals
Cold, damp or dusty air
Strong emotions

Question 5

What is found on examination of an asthma patient typically?

Answer 5

Examination usually normal with a widespread polyphonic expiratory wheeze heard on auscultation

Question 6

What conditions are asthma patients more likely to have?

Answer 6

Atopy:
-Eczema
-hay fever
-food allergies

Also FHx is strong

Question 7

What drugs can worsen asthma?

Answer 7

B-blockers - propranolol
NSAIDS

Question 8

Whats the pathophysiology of asthma?

Answer 8

-Airway epithelial damage - shedding and subepithelial fibrosis, BM thickening
-Infammatory reaction - eosinophils, Th2, mast cells, histamine, leukotrienes, prostaglandins
-Cytokines amplify infam response
-Increased no. Of mucus secreting goblet cells & smooth muscle hyperplasia and hypertrophy
-mucus plugging in severe asthma

Question 9

What investigations are done in suspected asthma?

Answer 9

-Spirometry w/ bronchodilator reversibility
-Fractional exhaled nitric oxide (FeNO)
-Peak flow variability (diary) 2-4wks
-Direct bronchial challenge testing

Question 10

What spirometry results would you expect in asthma?

Answer 10

Obstructive pattern - A FEV1:FVC ratio of less than 70%

Greater than 12% increase in FEV1 after salbutamol given

Question 11

What is fractional exhaled nitric oxide (FeNO)?

Answer 11

measures the concentration of nitric oxide exhaled by the patient - marker of airway inflammation
-steady exhale for around 10 seconds into a device that measures FeNO
-a level above 40 ppb is a positive test result
-results less reliable in smokers

Question 12

What is considered a positive result for peak flow variability?

Answer 12

A variability of more than 20%
Over 2-4wks

Question 13

What is direct bronchial challenge testing?

Answer 13

-Inhaled histamine or methacholine is used to stimulate bronchoconstriction, reducing the FEV1 in patients with asthma.
-PC20 (provocation concentration of methacholine causing a 20% reduction in FEV1) of 8 mg/ml or less is a positive test result.

Question 14

What are the BTS management steps of asthma?

Answer 14

-Short-acting beta-2 agonist inhaler (e.g. salbutamol) as required
-Inhaled corticosteroid (low dose) taken regularly
-Long-acting beta-2 agonists (e.g., salmeterol) or maintenance and reliever therapy (MART)
-Increase the inhaled corticosteroid or add a leukotriene receptor antagonist (e.g., montelukast)
-Specialist management (e.g., oral corticosteroids)

Question 15

What are some additional management steps suggested for asthma patients?

Answer 15

-Individual written asthma self-management plan
-Yearly flu jab
-Yearly asthma review when stable
-Regular exercise
-Avoid smoking (including passive smoke)
-Avoiding triggers where appropriate

Question 16

What is an acute asthma exacerbation?

Answer 16

Rapid deterioration in symptoms, normally caused by typical asthma triggers e.g. infection

Question 17

What are some presenting features of an acute asthma exacerbation?

Answer 17

-Progressively shortness of breath
-Use of accessory muscles
-Raised respiratory rate (tachypnoea)
-Symmetrical expiratory wheeze on auscultation
-The chest can sound “tight” on auscultation, with reduced air entry throughout

Question 18

How is acute asthma graded?

Answer 18

Based on presenting features:
-mild
-moderate
-severe
-life-threatening
-near fatal

Question 19

What are the features of mild asthma exacerbation?

Answer 19

PERF >75%
No severe asthma features

Question 20

What are the features of a moderate asthma exacerbation?

Answer 20

PERF 50-75% best or predicted

Question 21

What are the features of severe asthma exacerbation?

Answer 21

Peak flow 33-50% best or predicted
Respiratory rate above 25
Heart rate above 110
Unable to complete sentences in one breath

Question 22

What are the features of life-threatening asthma exacerbation?

Answer 22

Peak flow less than 33%
Oxygen saturations less than 92%
PaO2 less than 8 kPa
Becoming tired
Confusion or agitation
No wheeze or silent chest (no air entry)
Haemodynamic instability (shock)

Question 23

What are the features of life threatening asthma?

Answer 23

Raised CO2

Question 24

How is acute asthma exacerbation managed?

Answer 24

-ABCDE
• Aim for SpO2 94-98% with oxygen as needed, ABG if sats <92%
• 2.5-5mg nebulised Salbutamol (can repeat after 15 mins)
• 40mg oral Prednisolone STAT (IV Hydrocortisone if
PO not possible)

Question 25

How are severe and life-threatening asthma exacerbations managed?

Answer 25

If severe: • Nebulised Ipratropium Bromide 500 micrograms Consider back to back Salbutamol If life threatening or near fatal: • Urgent ITU or anaesthetist assessment : Aminophyline Urgent portable CXR • Consider IV Salbutamol if nebulised route ineffective

Question 26

What electrolyte must be managed with salbutamol use?

Answer 26

Serum potassium as salbutamol use can cause hypokalaemia

Question 27

What are some criteria for safe discharge following an acute asthma exacerbation?

Answer 27

- PEFR >75% • Stop regular nebulisers for 24 hours prior to discharge - Inpatient asthma nurse review to reassess inhaler technique and adherence - Provide PEFR meter and written asthma action plan - At least 5 days oral prednisolone - GP follow up within 2 working days - Respiratory Clinic follow up within 4 weeks - For severe or worse, consider psychosocial factors