Asthma Flashcards
Define Asthma and describe what it is characterised by
chronic airway inflammation
Variable reversible expiratory airflow limitation
Airway hyper-responsiveness
Describe the genetic aetiology/ risk factors of asthma
FHx
Atopy (T lymphocytes drive production of IgE on exposure to allergens)
Describe 7 environmental aetiology/ risk factors of asthma
House dust mites Pollen Pets Cigarette smoke Viral respiratory tract infections Aspergillus fumigatus spores Occupational allergens
Summarise the epidemiology of asthma
10% of children
5% of adults
Prevalence increasing
List 4 presenting symptoms of asthma
Episodic hx
Wheeze
Breathlessness
Cough (worse in the morning + at night)
What are 5 precipitating factors of asthma?
Cold Viral infection Drugs (e.g. b-blockers, NSAIDs) Exercise Emotions
What should you ask about when taking history of possible asthma?
Previous hospitalisation due to acute attacks- indicates severity of asthma
Hx of atopic disease: allergic rhinitis, urticaria, eczema
What are 5 signs of asthma on examination?
Tachypnoea Use of accessory muscles Prolonged expiratory phase Polyphonic wheeze Hyperinflated chest
List 4 signs a severe asthma attack
PEFR < 50% predicted
Pulse > 110/min
RR > 25/min
Inability to complete sentences
List 7 signs of a life-threatening asthma attack
PEFR < 33% predicted Silent chest Cyanosis Bradycardia Hypotension Confusion Coma
What 8 investigations are performed in acute asthma attacks?
Peak flow Pulse oximetry ABG CXR: exclude ddx (e.g. pneumonia, pneumothorax) FBC: raised WCC if infective exacerbation CRP U+Es Blood + sputum cultures
What 4 investigations are performed for chronic asthma?
Peak flow monitoring: often shows diurnal variation with a dip in the morning
Pulmonary function test
Bloods: Eosinophilia, IgE level, Aspergillus antibody titres
Skin prick tests: helps identify allergens
Describe the management of acute asthma attacks
ABCDE, Resuscitate Monitor O2 sats, ABG + PEFR High-flow O2, Salbutamol nebuliser, Ipratropium bromide Nebulized steroid therapy If no improvement, nebulize magnesium sulphate, or IV aminophilline / salbutamol Anaesthetic help if PCO2 increasing Treat cause: infection etc. May need ventilation in attacks
Why is a normal PCO2 is a BAD SIGN in a patient having an asthma attack?
Patient should be hyperventilating + blowing off their CO2, so PCO2 should be low
A normal PCO2 suggests patient is fatiguing
When and how do you discharge a patient after an acute asthma attack?
When PEF > 75% of predicted, discharge.
Stable on discharge medication for 24h
Check inhaler technique + appropriate regime, arrange follow up.
Describe the stepwise management of chronic asthma
NICE guidelines
- SABA (salbutamol)
- SABA + ICS
- SABA + ICS + LTRA
- SABA + ICS + LTRA + LABA
- a) + Increase ICS to mod-high dose
- b) + slow-release theophylline or Long acting muscarinic receptor antagonist
- Oral steroids
Give 3 pieces of advice to asthmatic patients
Teach proper inhaler technique
Explain importance of PEFR monitoring
Avoid provoking factors / allergens
List 6 possible complications of asthma
Growth retardation Chest wall deformity (e.g. pigeon chest) Recurrent infections Pneumothorax Respiratory failure Death
Describe the prognosis of asthma
Many children improve when older
Adult onset is chronic.
What 3 physiological factors contribute causes difficulty breathing air out of the lungs?
Bronchoconstriction
Airway wall thickening
Increased mucus
Give an example of each drug used in asthma
SABA: Salbutamol ICS: Beclometasone, Budesonide LABA: Formoterol LTRA: Montelukast Oral steroid: Prednisolone
What is the MOA of SABAs + LABAs?
Relaxes smooth muscle + dilates bronchioles
What is the MOA of ICS?
Suppress airway inflammation + reduce airway hyper-responsiveness
