Asthma

Question 1

Define Asthma

Answer 1

Chronic inflammatory airway disease characterised by variable reversible airway obstruction, airway hypersensitivity and bronchial inflammation

Question 2

What are the Risk factors for Asthma?

Answer 2

Genetic:

• Family History
• Atopy (tendency for T-lymphocytes to drive production of IgE on exposure to allergens)

Common Allergens: House dust mites, pollen, pets, cigarette smoke, viral respiratory tract infection Aspergillus fumigatus spores, occupational allergens

Question 3

What is the epidemiology of Asthma?

Answer 3

• Affects 10% of children, 5% of adults

- Prevalence appears to be increasing

Question 4

What are the presenting symptoms?

Answer 4

• Episodic history
• Wheeze
• Breathlessness
• Cough (worse in morning and night)
• Ask about in other atopic disease

Important: ask about previous hospitalised due to acute attacks - gives an indication on severity

Question 5

What are the precipitating factors of Asthma?

Answer 5

• Cold
• Viral Infection
• Drugs (e.g. beta-blockers, NSAIDs)
• Exercise
• Emotions

Question 6

What are the signs of Asthma?

Answer 6

• Tachnpnoea
• Use of accessory muscles
• Prolonged expiratory phase
• Polyphonic wheeze
• Hyperinflated chest

Severe attack:

• PEFR <50% predicted
• Pulse >110bpm
• RR> 25/min
• Inability to complete sentences

Life-Threatening attack:

• PEFR < 33% predicted
• Silent chest
• Cyanosis
• Bradycardia
• Hypotension
• Confusion
• Coma

Question 7

What Investigations are appropriate?

Answer 7

Acute:

• Peak flow
• Pulse Oximetry
• ABG
• CXR (to exclude other diagnoses)
• FBC, CRP, U&Es (raised WCC if infective exacerbation)
• Blood and sputum cultures

Chronic:

• Peak flow monitoring (often shows diurnal variation)
• Pulmonary function tests
• Bloods: check Eosinophilia, IgE lvel, Aspergillus antibody titres
• Skin prick tests (identify allergens)

Question 8

What is the Management for Acute Asthma?

Answer 8

• ABCDE; resuscitate
• Monitor O2 sats, ABG and PEFR
• High flow O2
• Salbumatol nebulizer (5mg, initially continuously, then 2-4hr)
• Ipratropium bromide (0.5mg QDS)
• Steroid therapy (100-200mg IV hydrocortisone, followed by 40mg oral prednisolone for 5-7days)
• No improvement => IV Magnesium sulphate
• Consider IV aminophylline infusion
• Consider IV salbutamol
• Anaesthetic help if patient is tiring
  Note: a normal PCO2 is a bad sign during an attack (they should hyperventilating so it should be low)
• A normal PCO2 suggest patient is fatiguing
• Treat underlying cause e.g. infection
• Give antibiotics if infective exacerbation
• Monitor electrolytes closely because bronchodilators and aminophylline causes a drop in K+
• Invasive ventilation may be needed in severe attack

Question 9

When criteria should be met before a patient is discharged?

Answer 9

• PEF >75% predicted
• Diurnal variation <25%
• Inhaler technique checked
• Stable on discharge medication for 24hr
• Patients owns a PEF meter
• Patient has steroid and bronchodilator therapy
• Arrange follow-up

Question 10

What is the management plan for Chronic Asthma?

Answer 10

Step 1:
- Inhaled short-acting beta-2 agonist used as needed
- If needed >1 a day -> step 2
Step 2:
- Step 1 + regular inhaled low-dose steroids (400mcg/day)
Step 3:
- Step 2 + long-acting beta-2 agonist (LABA)
- If inadequate control, increase steroid dose (800/mcg/day)
- If no response to LABA, stop it and increase steroid dose
Step 4:
- Increase inhaled steroid dose (2000 mcg/day)
- Add 4th drug (e.g. leukotriene antagonist, slow-release theophylline or beta-2 agonist tablet)
Step 5:
- Add regular oral steroids
- Maintain high-dose oral steroid
- Refer to specialist care

Advice: proper inhaler technique, explain importance of PEF monitoring, avoid provoking factors

Question 11

What are the complications of Asthma?

Answer 11

• Growth retardation
• Airway remodelling
• Chest wall deformity (e.g. pigeon chest)
• Recurrent infections
• Pneumothorax
• Respiratory failure
• Death

Question 12

What is the prognosis of Asthma?

Answer 12

• Most children improve with age

- Adult asthma tends to be chronic