Asthma

Question 1

What is asthma?

Answer 1

Refers to a common disease of the airways, involving reversible bronchoconstriction, hyperreactivity and chronic inflammation.

Question 2

Risk factors for asthma?

Answer 2

FHx of asthma or atopy
Personal history of atopy (eczema, allergic rhinitis, allergic conjunctivitis)
Exposure to smoke, including maternal smoking in pregnancy
Respiratory infections in infancy
Prematurity and low birth weight
Obesity
Social deprivation
Occupational exposures

Question 3

Presentation of asthma?

Answer 3

Wheeze
Dyspnoea
Cough
Chest tightness
Diurnal variation (worse at night or in the early morning).

Tachypnoea
Increased work of breathing
Hyperinflated chest
Expiratory polyphonic wheeze throughout the lung fields
Decreased air entry (if severe)

Question 4

Investigations for asthma?

Answer 4

FeNO (fractional exhaled nitric oxide) testing
- offer to all adults to confirm eosinophilic airway inflammation
- POSITIVE if >40 parts per billion

Spirometry
- offer to all >5years old to confirm airway obstruction (FEV1/FVC<70%)

Bronchodilator reversibility:
- if spirometry confirms obstruction, a bronchodilator is offered (e.g. salbutamol inhaler) to assess response to tx.
- improvement in FEV1 of ≥12% or 200ml is POSITIVE diagnosis.

Peak flow variability
- difference between high and low value >20% = POSITIVE

Direct bronchial challenge test
- histamine or metacholine is inhaled to trigger bronchoconstriction

Question 5

Management of chronic asthma in adults?

Answer 5

Non-pharmacological:
Smoking cessation
Advice on avoiding triggers where possible (e.g. allergens, certain medications)
Ensure vaccinations are up to date

Pharmacological:
Step 1: offer SABA to all pts

Step 2: + low dose ICS (if using SABA 3x a week or more)

Step 3: + LTRA

Step 4: + LABA

Step 5: If above tx does not work, offer LOW DOSE ICS + MART +/-LTRA.

Step 6: MODERATE ICS dose

Step 7: HIGH ICS dose or oral steroid or muscarinic receptor antagonist or theophylline

Answer 6

Pharmacological:
Step 1: offer SABA to all pts

Step 2: + very low/low dose ICS (if using SABA 3x a week or more)

Step 3: + LTRA (if age <5) OR + LTRA/LABA (age ≥5) (whilst taking very low dose ICS)

Step 4: increase to LOW-dose ICS if no response to LABA
or
+ LTRA and low dose ICS if some benefit from LABA

Step 5: increase to MEDIUM-dose ICS + theophylline

Step 6: + daily STEROID tablet (while using medium dose ICS)

Question 7

Management of acute asthma?

Answer 7

ABCDE
Titrate oxygen

Nebulised salbutamol driven by oxygen (if out of hospital, give up to 10 puffs of inhaled salbutamol and call an ambulance if not responding)

Add nebulised ipratropium bromide (if severe attack or no response to salbutamol)

Prednisolone 40-50mg orally, or IV hydrocortisone

IV magnesium sulphate and/or aminophylline if the patient is not responding to nebulisers

Question 8

Clinical features of moderate asthma?

Answer 8

PEFR > 50% of predicted or best

No features of severe/life-threatening asthma

Question 9

Clinical features of severe asthma?

Answer 9

PEFR 33-50% of predicted or best
HR >110
Respiratory rate >25
Unable to complete sentences in one breath.
Accessory muscle use

Question 10

Clinical features of life-threatening asthma?

Answer 10

PEFR < 33% of predicted or best
Oxygen saturation < 92% or cyanosis
Altered conciousness/confusion
Exhaustion/poor respiratory effort
Cardiac arrhythmia
Hypotension
Silent chest

Question 11

Investigations for acute asthma?

Answer 11

Peak expiratory flow rate (assess severity)
ABG (hypoxia)
CXR (pneumonia or pneumothorax)

Question 12

How do you distinguish asthma from bronchiectasis?

Answer 12

Bronchiectasis usually associated with a productive cough, patients get frequent chest infections and coarse crackles rather than wheeze predominate on examination..