asthma- andrew Flashcards
what is asthma?-WHO
It is a disease characterised by recurrent attacks of breathlessness and wheezing, which vary in severity and frequency from person to person. In an individual, they may occur from hour to hour and day to day.
what are the symptoms of asthma?
–variable and reversible airway obstruction
–airway inflammation
–bronchial hyper-responsiveness to various stimuli
what is the pathophysiology of asthma?
Chemical mediators are released by mast cells in airways: which cause:
1- bronchoconstriction
2- mucosal oedema
3-hypersecretion of mucus
overall this stops air getting to alveoli and into blood
what are the signs and symptoms of asthma?
- Breathlessness
- Tightness in the chest
- Coughing
- Wheezing
what are the most common causes and triggers of asthma?
Genetic links - not absolute –House dust mite –Animal allergens- e.g.cats –Pollens e.g.grass, trees –Infections - particularly viral –Occupational agents in workplace
what triggers asthma?
Drugs–3-5% of asthma population get severe bronchoconstriction after taking aspirin/NSAIDs
passive smoking-childhood
emotion/stress
exercise/extreme cold weather
how do you diagnose asthma?
clinical examination and full history- no certain blood tests you can do
some other investigations- FEV1/ peak flow can influence
it is important to compare the results when the patient is symptomatic and asymptomatic
what do you look out for in a structured clinical assessment for asthma?
HIGH PROBABILITY
- recurrent epsoides of symptoms/
- symptom variaility
- absense of symptoms of alternse diagnosis
LOW PROBABILITY OF ASTHMA
- wheeze?
- history of atopy
- variable PEV/FEV1
What is the test for airway obstruction?
spirometrey and bronchodilator reversibility
what happens in a structured clinical assessment?
Episodic symptoms
•Wheeze confirmed by a HCP on auscultation
•Evidence of diurnal variability
•Atopic history
•Absence of symptoms, signs or clinical history to suggest alternative diagnoses
what result of a spirometry test would suggest the presence of asthma?
Obstructive spirometry with positive reversibility increases probability of asthma
–Positive result: improvement in FEV1of ≥ 12% with an increase in volume of 200ml
–Improvement in FEV1of ≥ 400ml – strongly suggests asthma
what would be a positive result of a peak flow test to indicate that a person has asthma?
more than 20% variability- not a straight line
how does a peak flow work?
it is comapred to predicted peak flow based on persons diameters
what are the aims of management of asthma?
–Reduce inflammation
–Encourage brochodilatation
- control disease
what is complete control defined as?
–No daytime symptoms –No night time awakening due to asthma –No need for rescue medication –No asthma attacks –No limitations on activity including exercise –Normal lung function –Minimal side-effects from medication
what guidelines is BTS governed by?
NICE and BTS
What does the BTS approach suggest?
Start at the level most appropriate to initial severity
•Achieve early control
•Maintain control by:–Increasing treatment–Decreasing treatment
what are the types of drug treatment for asthma?
relievers and preventers
what are relivers?
Bronchodilators relax smooth muscle walls of airways e.g. salbutamol, ipratropium, theophylline
what are preventers?
anti inflammatory drugs which reduce inflammation in the airways
-orticosteroids, leukotriene receptor drugs
what are the differnces between NICE and BTS?
NICE–Introduction of LTRA after ICS
BTS/SIGN continues view that low-dose ICS should be followed by addition of long-acting beta-agonists (LABA)
what is the most effective combination?
Efficacy – ICS/LABA combination is most effective
•BUT…..generic LTRA now are ‘cost effective’ …role of NICE