Respiratory Treatment Flashcards
What are the pathophysiological changes in asthma?
Mucosal oedema Bronchoconstriction Mucous plugging Airway remodeling Bronchial hyperresponsiveness
What counteracts smooth muscle dysfunction?
Beta-2 agonists
(Short acting: salbutamol)
(Long acting: formoterol)
What reduces inflammation?
(cortico)steroids: inhaled (budesonide) and oral (prednisolone)
What occurs in airway remodelling?
Mucous gland hyperplasia Subepithelial fibrosis Epithelial desquamation Airway wall thickening Increased smooth muscle mass
What are the goals of asthma control?
Minimal symptoms during day and night
Minimal symptoms for reliever medication
No exacerbations or limitation of physical activity
Normal lung function (FEV1/PEF>80% predicted)
What is the treatment for mild intermittent asthma?
Short acting B2 agonists
(Salbutamol, terbutaline)
Symptom relief, reversal/prevention of bronchoconstriction, use as required (NOT regularly)
What occurs if short acting B2 agonists are used frequently?
Increased incidence of mast cell degranulation in response to allergen
What are the side effects of B2 agonists?
Adrenergic, therefore tachycardia, palpations, tremor
When should inhaled corticosteroids be given regularly as a preventer?
Using a B2 agonist >3 times/week
Symptoms >3 times/week
Waking >1 time/week
What is the main goal of regular corticosteroid use?
Reducing bronchial hyperresponsiveness
(Improves symptoms and lung function)
(Reduce exacerbations, prevent death)
What does the addition of a lipophilic side chain to corticosteroids confer?
High affinity for GCS receptor
Increase uptake and dwell time in tissue
Rapid inactivation following systematic absorption (GI, liver eliminates on first pass)
Can systemic side effects occur with inhaled corticosteroids?
Yes, in high doses - may result in adrenal crisis
What is the first choice for add-on therapy?
Long acting B2 agonists (formoterol, salmeterol)
Give when not controlled on 400mcg/day ICS
What are the main uses of LABAs?
Reduce asthma exacerbations
Improve symptoms
Improve lung function
Not anti-inflammatory by themselves - give with ICS
Should combination inhalers be given?
Yes - means that patients will take all of their medications
What are alternative possible add-on therapies?
High dose ICS
Leukotriene receptor antagonists
Theophylline
Tiotropium
What is the main action of leukotriene receptor antagonists?
Prevents action of LTC4 released by mast cells
Bronchoconstriction, mucous secretion, mucosal oedema, inflammatory cell recruitment
What are the side effects of leukotriene receptor antagonists?
Angioedema Dry mouth Anaphylaxis Fever Gastric disturbance Nightmares (No important drug interactions)
What is the main action of methylxanthines?
Antagonise adenosine receptors
What are the side effect of methylxanthines?
Nausea, headache, reflux
Toxic complications - arrhythmia, fits
When are long acting anticholinergics (LAMAs) given?
COPD and severe asthma
(Reduces severe exacerbations, some improvement in symptoms and lung function)
(Relative M3 muscarinic receptor selectivity)
What are the side effects of LAMAs such as tiotropium bromide?
Dry mouth
Urinary retention
Glaucoma
What is given at step 5?
Oral steroids (~10mg/daily, more for maintenance therapy)
Biological therapies
Anti-IGE (omalizumab) prevents IGE binding to high affinity IGE receptor, preventing mast cell activation
Anti IL-5 (eg mepolizumab) reduces peripheral blood and airway eosinophil count (reduces rate of severe asthma exacerbations)
When should patients step down?
Once asthma is controlled, to prevent higher doses than necessary (maintain at lowest possible dose of inhaled steroid)
What qualifies as severe asthma in adults?
Unable to complete sentences Pulse > 110bpm Respiration > 25/Mon Peak flow 33-50% best/predicted (Plus any of silent chest, cyanosis, hypotension, bradycardia, arrhythmia, exhaustion, confusion, coma)
What qualifies as near-fatal?
PaCO2 >6kPa
Mechanical ventilation
How is severe acute asthma treated?
High flow oxygen - aim for 94-98% says
Nebulised salbutamol, continuous if necessary, O2 driven
Oral prednisolone (~40mg/day, 10-14 days)
If not responding, add nebulised ipratropium bromide
If no improvement and life threatening features, consider IV aminophylline
What is ipratropium bromide?
A quaternary anticholinergic agent
Slow and less intense bronchodilator (lasts up to 6 hours)
