Asthma

Question 1

Define Asthma and summarise its aetiology and epidemiology

Answer 1

Definition: Chronic inflammatory airway disease characterised by variable reversible airway obstruction, airway hyper-responsiveness and bronchial inflammation.

Risk factors:
Genetic factors-
- Family history
- Atopy (tendency for T lymphocytes to drive production of IgE on exposure to allergens)

Environmental factors-

• House dust mites
• Pollen
• Pets
• Cigarette smoke
• Viral respiratory tract infections
• Aspergillus fumigatus spores
• Occupational allergens

Epidemiology:

• Affects 10% of children
• Affects 5% of adults
• Prevalence appears to be increasing

Question 2

Describe the typical history/presenting symptoms of asthma

Answer 2

Episodic history 
Wheeze 
Breathlessness
Cough 
IMPORTANT: ask about previous hospitalization due to acute attacks- this gives an indication of the severity of the asthma.

Precipitating Factors:

• Cold
• Viral infection
• Drugs (e.g. beta-blockers, NSAIDs)
• Exercise
• Emotions
• Atopic disease (e.g. allergic rhinitis, urticaria, eczema)

Question 3

What are the signs of asthma upon physical examination?

Answer 3

Tachypnoea
Use of accessory muscles 
Prolonged expiratory phase
Polyphonic wheeze
Hyperinflated 

Severe Attack:

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

Life-Threatening Attack:

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

Question 4

Identify appropriate investigations for asthma

Answer 4

Acute:
1st investigations to order
- peak flow measurement (peak expiratory flow or FEV1)
- oxygen saturation
- short-acting bronchodilator trial
- Pulse oximetry

Investigations to consider

• ABG
• chest x-ray- to exclude other diagnosis e.g. pneumonia, pneumothorax
• U&Es
• Blood and sputum cultures
• CRP and FBC

Chronic:
- Peak flow monitoring- often shows diurnal variation with a dip in the morning 
- Pulmonary function test
- Blood- Check:
    Eosinophilia
    IgE level
    Aspergillus antibody titres
  Skin prick tests- helps identify allergens

Question 5

Generate a management plan for acute Asthma attacks

Answer 5

• Resuscitate; ABCDE
• Monitor O2 sats, ABG and PEFR
• High-flow Oxygen
• Salbutamol nebulizer (5mg, initially continuously, then 2-4 hourly)
• Ipratropium bromide (0.5mg QDS)
• Steroid therapy:
  100-200mg 1V hydrocortisone followed by, 40mg oral prednisolone for 5-7 days
• If no improvement- IV magnesium sulphate or consider IV aminophylline infusion.
• Consider IV salbutamol
• Anaesthetic help may be needed if the patient is getting exhausted.
• NOTE: a normal PCO2 is a bad sign in a patient having an asthma attack as during an attack they should be hyperventilating and blowing off their CO2 so it should be low.
• Treat underlying cause (e.g. infection)
• Give antibiotics if it is an infective exacerbation
  -Monitor electrolytes closely because bronchodilators and aminophylline causes a drop K+
• Invasive ventilation may be needed in sever attacks

Discharge when:

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

Question 6

Generate a management plan for chronic Athma

Answer 6

Start on the step that matches the severity of the patient’s asthma
Step 1:
- Inhaled short-acting beta-2 agonist used as needed
- If needed >1/day then move onto step 2

Step 2:
- Step 1+ regular inhaled low-dose steroids (400mcg/day)

Step 3:

• Step 2+ inhaled long-acting neta-2 agonist (LABA)
• If LABA is inadequate, increase steroid dose (800 mcg/day)
• If no response stop LABA and increase steroid dose (800mcg/day)

Step 4:

• Increase inhaled steroid (2000mcg/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 steroids
• Refer to specialist care

Advice:

• Teach proper inhaler technique
• Explain importance of PEFR monitoring
• Avoid provoking factors

Question 7

Identify the possible complications of asthma

Answer 7

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

Question 8

Summarise the prognosis for patients with asthma

Answer 8

• Many children improve as they grow older

- Adult-onset asthma is usually chronic