Week 4: Respiratory - Asthma, COPD, Nicotine Cessation Flashcards
What is the pathophysiology of asthma?
Asthma causes the stimulation of IgE antibodies which causes mast cell activation or degranulation - leads to inflammation and mucus production causing the flare of asthma
Acute inflammation - symptoms (bronchoconstriction)
Chronic inflammation - exacerbations nonspecific hyperreactivity
Airway remodeling - persistent airflow obstruction
Symptoms of Asthma
Symptoms include
- Increase mucus production
- Thickened bronchial walls
- Wheeze
- Shortness of breath
- Chest tightness
- Cough
- Expiratory airflow limitation
Pathophysiological effects of asthma attack
- Altered immunological response -> chemical mediators released (histamine, protaglandins, bradykinins etc.
- Increased airway resistance -> mucus secretion, inflammation, bronchospasm
- Increased lung compliance -> lungs become hyper-inflated
- Impaired mucocillary function -> increased mucus production (can cause cough)
- Altered O2-CO2 exhcange -> increased airway resistance
Asthma effect on airways
Asthmatic airway during attack
- Tightned smooth muscles, wall inflamed and thickened, enlarged alveolar as air is trapped
How to control asthma?
- Good control
- Partial control
- Poor control
Good control (all of following)
- Daytime symptoms <2 days per week
- Need for reliever <2 days per week
- No limitation of activities
- No symptoms during night or on waking
Partial control (one or two of following)
- Daytime symptoms >2 days per week
- Need for reliever >2 days per week
- Any limitation of activities
- Any symptoms during night or on waking
Poor control (three or more of following)
- Daytime symptoms >2 days per week
- Need for reliever >2 days per week
- Any limitation of activity
- Any symptoms during night or on waking
Lifestyle management of ashma
- Smoking cessation (including second degree)
- Identify and avoid triggers
- Manage comorbidities
- Healthy eating and body weight
- Regular physical activity
- Regular immunisations
Pharmaceutical management options for asthma
Short acting beta agonist (SABA)
Long acting beta agonist (LABA)
Inhaled corticosteroids (ICS)
SABA
- MOA
- Clinical use
- Drug options
MOA
- Agonist of beta-2-adrenergic receptors in lungs
- Cause bronchodilation by relaxing bronchial smooth muscle and allowing airway to open
Clinical use
- Relievers
- Used as needed to relieve symptoms
- May be used before exercise
- Rapid onset 3-4 min
- Duration of 3-4 hrs
Drug options
- Salbutamol (Ventolin, Asmol)
- Terbutaline (Bricanyl)
Contraindications/Cautions of SABA
Pregnancy/Breastfeeding/Heptic impairment/Renal impairment
- Safe
Elderly:
- Start with low dose and slowly titrate
Children:
- Safe for children aged 2+ (need specialist if younger)
Cautions in:
- CVD
- Hyperthyroidism
- Diabetes
- History of PACG
- Other sympathomimetics
- Corticosteroids
- Theophyline
- Diuretics
LABA
- MOA
- Clinical use
- Drug options
MOA
- Agonist of beta 3 adrenergic receptors
- Activate receptors in bronchial smooth muscles to allow relaxation and bronchodilation
Clinical use
- Preventor
Drug options
- Salmeterol (Serevent, Seretide)
- Eformoterol (Oxis, Symbicort)
- Indacaterol (Onbrez)
Contraindications/cautions of LABA
Hepatic and renal impairment
- No precautions
Elderly:
- Start low dose and slowly titrate
Pregnancy:
- Limited data
Breastfeeding:
- Salmeterol is safe
Children:
- Safe for children 2+ (specialist if younger)
Cautions in:
- CVD
- Hyperthyroidism
- Diabetes
- History of PACG
- Other sympathomimetics
- Corticosteroids
- Theophyline
- Diuretics
ICS
- MOA
- Clinical use
- Drug options
MOA
- Immunosuppressant
- Reduce airway inflammation and bronchial hyper-reactivity
Clinical use
- Maintenance therapy
- Can be combined with LABA or given on its own
- Useful for prevention even if only occasional flare up
Drug options
- Beclomethasone (QVAR)
- Budesonide (Pulmicort)
- Fluticasone (Flixotide, Breo)
Contraindications/cautions for ICS
Pregnancy/breastfeeding/hepatic impairment/renal impairment:
- Safe and no precautions
Elderly:
- More susceptible to skin thinning and bruising
- Use lower dose
Children:
- Avoid high dose without specialist involvement
Cautions in:
- COPD (pneumonia risk)
Inhaled Anticholinergics
- MOA
- Clinical use
- Drug options
MOA
- Antagonist of cholinergic receptors in bronchial tissue
- Relax smooth muscle to allow bronchodilation
- Specifically antagonise the muscarinic effects of cholingeric receptors (also referred to as SAMA or LAMA)
Clinical use:
- Short acting (SAMA) -> relief of asthma symptoms
- Long acting (LAMA) -> maintenance/prevention of asthma symptoms in combination with LABA or ICS
Drug options
- Short acting -> Ipratropium
- Long acting -> Tiotripium
Contraindications/Cautions of inhaled anticholingeric
Pregnancy/Breastfeeding/Hepatic impairment/Renal impairment:
- Safe and no cautions
Elderly:
- Likely to be susceptible to urinary retension
Children:
- SAMA can be used
- LAMA’s cannot
Caution in:
- Bladder obstruction/urinary retension or PACG