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
what do bronchodilators (SAB2A) DO?
Relieve symptoms–Activation of β2-receptors results in relaxation of smooth muscle - widening of the airway
what should all symptomatic patients of asthma be prescribed?
All patients with symptomatic asthma should be prescribed inhaled SAB2A.- e.g. salbutamol
good to treat exacerbation but nit preventor
how fast do SAB2A act?
Act within 5 -10 mins–Last 4 - 6 hours
are the bronchodilators selective?
Selective but ß2receptors present in cardiac tissue.
-So overuse(oral forms) – cardiac s/e- tachycardia- dilation of blood vessels
what is the max number of SAB2A you should be prescribed per month?
1- if more need to be assessed
what do the anticholenergic bronchodilators do?
Block acetylcholine receptors in the respiratory tree
Used mainly as add on therapy to B2agonists
•Example: ipratropium
what are the s/e of anticholergics?
dry mouth & large doses systemic side effects
what kind of drugs are corticoid steroids?
anti-inflamatory
how do corticosteroids work?
Thought to inhibit mediators involved in airway inflammation
•Examples: –Inhaled: Beclometasone, budesonide–Oral: prednisolone (severe attack)
what are the low dose s/e of ICS?
oral thrush –hoarseness–rinse mouth with water after dose, use spacer device
What allerts regrowth in children?
CSM alert re growth in children
when are corticoidsteroids used?
Recommended preventer drug to achieve overall treatment goals
when do you consider using Corticosteroids?
Asthma attack in the last 2 years
–Using inhaled SAB2A 3 times per week or more
–Symptomatic 3 times per week or more
–Waking 1 night per week
how do you prescribe ICS?
start at low dose- appropriate for the severity
use the lowest dose for effective control
when is ICS more effective?
when taken twice daily
what should be avoided in ICS prescribing?
Generic prescribing of inhalers should be avoided – brand prescribing- as they are not interchangable
who usually needs a higher dose?
smokers/ ex-smokers
when should LAB2A be used?
Added to short acting B2agonists & ICS–Improves lung function and symptoms–Decreases asthma attacks
e.g. salmeterol
what must LAB2A be used in comb with?
ICS
why do we use combination inhalers?
less devices- better compliance
more practical
No difference in efficacy to separate inhalers
what are some examples of combination inhalers?
Beclometasone/formoterol: Fostair
–Budesonide/formoterol: DuoResp, Symbicort
–Fluticasone propionate/salmeterol: Seretide
–Fluticasone furoate/vilanterol: Relvar
what types of add on therapys can you use?
Leukotriene receptor antagonists-
Methylxanthines-oral
Tiotropium
what do Leukotriene receptor antagonists do?
Block leukotriene mediators in airways
•Examples: montelukast
what do Methylxanthines-oral do?
Mode of action unclear•Example: theophylline Drug interactions common •Narrow therapeutic window – Pxby brand •Monitor blood levels •Side effects- GI
what does Tiotropium do?
Fewer exacerbations of asthma
–Improved lung function
–Benefits to asthma control
why would you decrease therapy?
cautious about long term s/e
When good control is established
how would you decrease therapy?
–ICS: stable patients, consider reducing dose by 25 – 50% every 3 months
what are the common therapeutic problems associated with asthma?
Under diagnosed
•Failing to avoid / reduce exposure to allergens
•Lack of patient knowledge about condition and its management
•When to start ICS Tx
•Taking ICS “prn”
•Missing signs of deteriorating asthma control
•Poor technique – poor compliance
how do you differenciate betweem the different types of asthma?
look at the oxygen sat/ speach/ pulse
/respiration/pef
how would you clasify acute asthma?
PEF> 50-70% oxygen >92% normal speach resp <25 breaths/min pulse<110 bpm
what is the treatment for acute asthma?
Oxygen–Steroids–SAB2A–SAMA–Magnesium sulphate
what is supported self- managment?
Education– Disease– Symptom recognition– Review– Compliance/Inhaler technique
what type of non-pharmacological managment is there?
Avoid known allergens and triggers• Difficult, expensive, time consuming– Stop smoking, exposure to passive smoking– Breathing exercises– Ideal body weight
what else can the pharmacist to to help the patient manage their asthma?
action plan leafelet
