Asthma Flashcards
What is Asthma?
- Chronic inflammatory condition causing episodic exacerbations of bronchoconstriction
- Narrowing of the airways causes an obstruction to airflow going in and out of the lungs
Is airway obstruction in asthma reversible?
Yes usually triggers by environmental factors and can be reversed by bronchodilators e.g. salbutamol
What are common asthma triggers?
- Infection
- Night time/early morning
- Exercise
- Animals
- Cold/damp
- Dust
- Strong emotions
How would an asthmatic present?
- episodic episodes
- Diurnal variability
- Dry cough, breathlessness and wheeze
- history of other atopic conditions e.g. eczema, hay fever and food allergies
- family history of asthma
- Bilateral widespread polyphonic wheeze
What presentations suggest diagnosis is NOT asthma?
- Wheeze related to cough/cold
- isolated productive cough
- normal investigations
- No response to treatment
- unilateral wheeze (suggests focal lesion or infection)
How is asthma diagnosed (according to NICE guidelines)?
- Diagnosis made only after testing, first line investigations are:
1) fractional exhaled NO
2) Spirometry with bronchodilator reversibility - If diagnosis uncertain test:
3) peak flow variability
4) Direct Bronchial challenge test with histamine or methacholine
What are the treatments for asthma and give an example of each?
- Short acting beta 2 adrenergic receptor agonist (salbutamol)
- inhaled corticosteroids (beclometasone)
- Long acting beta 2 agonist (salmeterol)
- Long acting muscarinic antagonist (tiotropium)
- Leukotriene receptor agonist (montelukast)
- Theophylline
- Maintenance and reliever therapy
How do Short and long acting beta 2 adrenergic receptor agonist work?
- Adrenaline acts on the smooth muscle of the airways to cause relaxation
- bronchioles dilate
- Short used as relievers
- Long have longer action
How do inhaled corticosteroids work?
- reduce inflammation and reactivity of the airways
- maintenance/preventer medication
How do Long acting muscarinic antagonists work?
- block acetyl choline receptors
- acetyl choline receptors are normally stimulated by parasympathetic nervous system to cause contraction
- therefore causes dilation
How do Leukotriene receptor agonist work?
- Leukotrienes usually produced by immune system and cause inflammation, bronchoconstriction and mucus secretion
- agonists block the action of leukotrienes
How does Theophylline work?
Relaxes bronchial smooth muscle and reduces inflammation
What is the downfall of Theophylline?
- Narrow therapeutic window
- needs close monitoring to ensure not at toxic dose
- check levels 5 days after treatment starts and 3 days after each dose change
What is Maintenance and reliever therapy?
- combination inhaler containing low dose corticosteroids and fast acting LABA
- can replace all other inhalers, patient able to need only one inhaler as preventer and reliever
What are the principles of the stepwise ladder of asthmas treatment?
- Start at most appropriate step for severity of symptoms
- review at regular intervals based on severity
- Step up and down ladder based on symptoms
- aim to achieve no symptoms or exacerbations on lowest dose and number of treatments
- Always check inhaler technique and adherence
