Asthma and Bronchodilators Flashcards
What is asthma?
Variable narrowing of the airways
What are the 2 features of pathophysiology of asthma?
- Smooth muscle abnormalities: hyperresponsiveness and hypertrophy
- Airway inflammation
How to diagnose asthma?
Spirometry
Peak expiratory flow
What does asthma eventually lead to?
Airflow obstruction
What factors can lead to variable airflow obstruction? (4 points)
- Triggers such as exercise and irritants
- Spontaneous diurnal variation
- Response to treatment
- Exposure to allergens
In people with asthma, lung function can be normal. True or false?
True
What are symptoms of asthma?
Wheeze, breathlessness, chest tightness
Variable symptoms usually worse at night or early morning; worse with exercise, irritant exposures, cold air etc
Cough, sputum
What are some non-pharmacological treatment options for asthma?
Stop smoking
Avoid triggers
Weight loss
What are the 2 types of pharmacological asthma treatment (inhalers)?
Bronchodilators (relievers)
Anti-inflammatory agents (preventers)
What drugs are classed under the bronchodilators “relievers”? (4 points)
Beta adrenergic agonists
Anticholinergics
Theophylline
Magnesium
What drugs are classed under anti-inflammatory agents “preventers”? (3 points)
Corticosteroids
Leukotriene antagonists
Anti IgE antibodies
What nerve supplies the parasympathetic nervous system of the airway smooth muscle (constriction)?
Vagus
What 1) receptor and 2) hormone stimulate the sympathetic nervous system of the airway smooth muscle (relaxation and dilatation)?
1) β2 adrenergic receptor
2) Circulating adrenergic hormones eg adrenaline
What 1) molecule and 2) ionic changes contribute to the constriction and dilatation of the airway smooth muscles?
1) cAMP
2) Changes in intracellular calcium
How do anticholinergics work to dilate the bronchus/airway?
They block off the vagus nerve, allowing the β2 receptor to take over
What can act on β2 receptors and lead to an increase in cAMP causing bronchodilation?
β2 agonists
How does theophylline work as a bronchodilator?
Blocks the break down of cAMP therefore causing an increase of intracellular calcium which increases smooth muscle relaxation
How does magnesium work as a bronchodilator, usually for life-threatening asthma cases?
Displaces intracellular calcium causing potent and rapid airway smooth muscle dilation
What are the different types of beta adrenergic agonists (asthma treatment) and examples?
Short acting ‘relievers’ eg Salbutamol/ventolin, Terbutaline (duration 2-4 hours)
Long acting eg Salmeterol, Formoterol (duration 12 hours)
Oral
Intravenous
What colour is the salbutamol/ventolin inhaler?
Blue
What is an example of a powder inhaler?
Terbutaline
What are the effects of beta adrenergic agonists? (5 points)
- Bronchodilation
- Tachycardia
- Hypokalaemia
- Hyperglycaemia
- Tachyphylaxis (if a drug is used repeatedly, receptors are worn out and drug no longer has an effect)
What are examples of anticholinergics and how do they treat asthma?
Ipratropium and Tiotropium
Inhibit vagal tone
What are the side effects of anticholinergics? (3 points)
- Dry mouth
- Glaucoma
- Urinary retention
Theophylline is a ________ derivative. It can be prepared __________ and intravenously. It has a _______ therapeutic window. The drug that it interacts with and is dangerous in overdose is _____________. Possible side effects include tachyarrthythmias, ventricular fibrillation and _____________.
Caffeine. Orally. Narrow. Erythromycin. Convulsions.
How is magnesium usually administered?
Intravenously
What are the three drug classes of anti-inflammatory agents “preventers” of asthma treatment?
Corticosteroids
Leukotriene antagonists
Anti-IgE antibodies
What are the different types and examples of corticosteroids “preventers” asthma treatment?
Inhaled: beclomethasone, budesonide, fluticasone
Oral: prednisolone
Intravenous
What are the possible side effects of corticosteroids “preventers”?
Inhaled: oropharyngeal candidiasis, dysphonia, bruising, cataracts
Oral: osteoporosis, skin thinning, hypertension, adrenal suppression, diabetes
Leukotriene antagonists are _____ that are not very effective so not many people take it.
Tablets
What do leukotriene antagonists and anti-IgE antibodies target when treating asthma?
Allergens (eg cat, house dust mite) + Specific IgE antibodies -> release of inflammatory mediators from mast and other cells
In combination inhalers, what are the combined drugs?
Inhaled corticosteroid + long acting beta agonist
What are some examples of combination inhalers?
Seretide: salmeterol + fluticasone
Symbicort: formoterol + budesonide
What are the different devices used during asthma treatment that help get the drug into the patient’s lungs through the small airways?
- Pressurised metered-dose inhalers
- Spacer devices
- Self-actuating devices
- Dry powder inhalers
- Nebulisers
Pressurised metered-dose inhalers are convenient but they require ________ and high ________ _______ as they are breath actuated devices. They have ____________ ____________.
Coordination. Inspiratory flow. Oropharyngeal deposition
Spacer devices (decrease/increase) the need for coordination. They (decrease/increase) oropharyngeal deposition and (decrease/increase) airway deposition.
Decrease
Decrease
Increase
Dry powder devices usually require (higher/lower) inspiratory flow rate. (More/less) coordination is needed. They do not contain propellant.
Lower. Less.
Nebulisers can administer very (high/low) doses but they are very inefficient. They may delay hospital admission.
High
How to manage acute severe asthma?
- Assess the severity
- Summon help
- Support the patient to sit up
- Give high dose of bronchodilator (use nebuliser if avaible; improvise spacer device; salbutamol inhaler)
- Give corticosteroids/oxygen
Assessing asthma severity
- Moderate asthma exacerbation: increasing symptoms, PEF >__ - __% best or predicted, no features of acute severe asthma
- Acute severe asthma: any one of PEF __ - __% best or predicted, respiratory rate >=25/min, heart rate >=110/min, inability to complete sentences in one breath
- Life threatening asthma: any one of PEF < __% best or predicted, SpO2 < 92%, PaO2 < 8kPa, ‘normal’ PaCO2 4.6-6.0kPa, clincal signs of altered conscious level, exhaustion, arrhythmia, hypotension, cyanosis, silent chest, and poor respiratory effort.
- Near-fatal asthma: raised PaCO2 and/or requiring mechanical ventilation with raised inflation pressures
> 50-75%
33-50%
<33%
