Asthma

Question 1

What is asthma?

Answer 1

Asthma is an obstructive respiratory disease characterised by chronic airway inflammation, bronchial hyperresponsiveness and intermittent airway narrowing.

In clinical practice, it is defined by the presence of both respiratory symptoms (e.g. wheeze, dyspnoea, chest tightness or cough) and excessive variation in lung function.

Question 2

What are some possible causes for episodic asthma exacerbations?

Answer 2

1. Allergen or irritant exposure
2. Exercise
3. Respiratory (viral) infections
4. Poor compliance with prescribed medications
5. Extreme weather events (‘thunderstorm asthma’)

Question 3

What are the clinical features of asthma?

Answer 3

1. Wheeze
2. Dyspnoea
3. Chest tightness or cough
4. Tachypnoea
5. Tachycardia
6. Accessory muscle usage
7. Diaphoresis
8. Cyanosis (late sign)

Question 4

What are the categories & clinical features used to classify the severity of asthma?

Answer 4

1. Mild/moderate
2. Severe
3. Life-threatening
4. Mild/moderate:
   - Alert
   - Mildly anxious
   - Speaks in sentences
   - RR <25 adults, <30 paeds over 5 yrs or <40 paeds 2-5 yrs
   - Slightly prolonged expiratory phase
   - Accessory muscle use
   - Pale
   - PR <110 adults, <120 paeds over 5 yrs or <140 paeds 2-5 yrs
   - Expiratory wheeze
   - SP02 90-94%
5. Severe:
   - Altered
   - Distressed, agitated
   - Speaks in words
   - RR >25 adults, >30 paeds over 5 yrs or >40 paeds 2-5 yrs
   - Marked prolonged expiratory phase
   - Accessory muscle use, intercostal retraction, tracheal tug
   - Pale, sweating
   - PR <110 adults, <120 paeds over 5 yrs or <140 paeds 2-5 yrs
   - Expiratory wheeze, inspiratory wheeze
   - SP02 <90%
6. Life-threatening:
   - Altered or unconscious
   - Exhausted, catatonic
   - Unable to speak
   - RR silent chest
   - Marked prolonged expiratory phase, no respiratory pause
   - Poor respiratory effort; respiratory exhaustion
   - Pale, sweating, cyanosis (late sign)
   - PR hypotension/bradycardia, arrhythmia
   - Expiratory wheeze, inspiratory wheeze
   - SP02 88%

Question 4

What are the categories and clinical features used to classify the severity of asthma?

Answer 4

Mild/moderate, Severe or Life-threatening

1. Mild/moderate:
   - Alert
   - Mildly anxious
   - Speaks in sentences
   - RR <25 adults, <30 paeds over 5 yrs or <40 paeds 2-5 yrs
   - Slightly prolonged expiratory phase
   - Accessory muscle use
   - Pale
   - PR <110 adults, <120 paeds over 5 yrs or <140 paeds 2-5 yrs
   - Expiratory wheeze
   - SP02 90-94%
2. Severe:
   - Altered
   - Distressed, agitated
   - Speaks in words
   - RR >25 adults, >30 paeds over 5 yrs or >40 paeds 2-5 yrs
   - Marked prolonged expiratory phase
   - Accessory muscle use, intercostal retraction, tracheal tugging
   - Pale, sweating
   - PR >110 adults, >120 paeds over 5 yrs or >140 paeds 2-5 yrs
   - Expiratory wheeze, inspiratory wheeze
   - SP02 <90%
3. Life-threatening:
   - Altered or unconscious
   - Exhausted, catatonic
   - Unable to speak
   - RR silent chest
   - Marked prolonged expiratory phase, no respiratory pause
   - Poor respiratory effort, respiratory exhaustion
   - Pale, sweating, cyanosis (late sign)
   - PR hypotension/bradycardia, arrhythmia
   - Expiratory wheeze, inspiratory wheeze
   - SP02 <88%

Question 5

What are potential differential diagnoses for asthma?

Answer 5

1. Cardiac failure
2. COPD
3. Pulmonary disease
4. Foreign body
5. Smoke inhalation

Question 6

How are the different severities of asthma treated?

Answer 6

Mild/moderate:

1. O2
2. Salbutamol (NEB)
3. Ipratropium bromide (NEB)
4. Hydrocortisone (IM/IV)

Severe:

1. O2
2. Salbutamol (NEB)
3. Ipratropium bromide (NEB)
4. Hydrocortisone (IM/IV)
5. Adrenaline (IM)
6. Magnesium sulphate (CCP)
7. CPAP (CCP)

Life-threatening:

1. O2
2. Salbutamol (NEB)
3. Ipratropium bromide (NEB)
4. Hydrocortisone (IM/IV)
5. Adrenaline (IM)
6. Magnesium sulphate (CCP)
7. If RR <10 & deemed inadequate, commence IPPV with NEB medications
8. CPAP (CCP)