Asthma Flashcards
What is asthma
Recurrent episodes of dyspnoea, cough and wheeze caused by reversible airway obstruction
Asthma triggers
Cold air + pollution Exercise Emotion Allergens Infection NSAIDs + beta blockers
Asthma diurnal variation
Peak flow and symptoms vary over day, often worst in mornings
Asthma signs + symptoms
Dyspnoea, cough (often nocturnal), wheeze
Hyperinflated chest
Hyper-resonant percussion
Widespread polyphonic wheeze
Asthma history considerations
Exercise tolerance
Sleep disturbed for severity assessment
Other atopic disease
Work and home triggers
Asthma severe attack signs
Inability to complete sentences
Pulse >110
RR >25
PEF 33-50% predicted
Asthma life threatening attack signs
Silent chest Confusion, exhaustion Cyanosis Bradycardia Inc PaCO2 if near fatal PEF<33%
Asthma acute attack tests
PEF
Sputum + blood cultures
ABG shows normal/slightly low PaO2 and low PaCO2
If CO2 rising transfer to HDU/ITU as ventilation inadequate
Asthma chronic tests
PEF monitoring
Spirometry shows obstructive defect (dec FEV1/FVC, inc RV)
FeNO test if unsure diagnosis, especially in children
CXR shows hyperinflation
Skin-prick may help with allergens
Asthma associated conditions
Acid reflux
Polyarteritis nodosa
ABPA
Churg-Strauss vasculitis
Asthma diagnosis + when to refer
Spirometry or PEF if spirometry not possible
FEV1/FVC<0.7 trial asthma treatment, if >0.7 refer to treat other cause
If treatment unsuccessful, assess inhaler technique + compliance then refer
Chronic asthma management - lifestyle
Quit smoking
Avoid precipitants
Weight to ideal
Inhaler technique
2x daily PEF monitoring
Teach how to use medications and action plan for attack
Chronic asthma management - drugs
SABA as needed, if >1/d or night symptoms go down
Add beclometasone 200-400µg/d
Add montelukast
Add LABA (salmeterol 50µg/12h)
Change to maintenance + reliever therapy (LABA+ICS)
Increase ICS dose in MART to 800µg
Add LAMA or theophylline + refer
beta2 agonist MOA
Relax bronchial smooth muscle by increasing cAMP
beta2 agonist SE
Tremor Anxiety Tachyarrythmias Hypokalaemia Paradoxical bronchospasm with LABAs
Corticosteroid MOA in asthma
Decrease bronchial mucosal inflammation
Aminophylline MOA
Metabolised to theophylline which is a PDE inhibitor, dec bronchoconstriction by inc cAMP
Aminophylline issues
Brand name bioavailability variability so stick with 1 brand
Narrow therapeutic window
Arrythmias
GI upset
Fits
Anticholinergics usage
Ipratropium, Tiotropium
COPD more than asthma
Cromoglicate MOA
Mast cell stabiliser
Cromoglicate usage
Prophylaxis in mild + exercise induced asthma, especially in children
Leukotriene receptor antagonist MOA
Block cysteinyl leukotriene effects in airways by antagonising CystLT1 receptor
Anti-IgE monoclonal Ab usage
Omalizumab may be used in persistent allergic asthma, subcut 2-4wks
Prescribed by specialists only
Acute severe asthma management
Salbutamol 5mg nebulised with O2 + pred 30mg PO
If PEF <75% repeat salbutamol, add ipratropium
Monitor sats, HR, RR, ECG
Consider single 1.2-2g MgSO4 IV over 20 mins for poor responders to initial Rx
