Asthma pathophysiology Flashcards
Outline the effects of LABA’s
Reduced bronchoconstriction Reduced bronchohyperactivity Reduced hyperplasia Reduced inflammatory mediator release Reduced mucousal oedema and tissue remodeling
Outline the effects of inhaled steroids
Reduced bronchohyperactivity Reduced inflammatory cell conc. Reduced oedema Reduced epithelial damage Reduced tissue remodeling Reduced cell proliferation
Why is asthma still such a problem?
Under diagnosed and undertreated
Misdiagnosed and mistreated
Patient compliance with treatment is poor
What factors indicate a high probability of asthma?
Cough + wheeze Cough is worse at night Exercise induced Family history of asthma Evidence of airway narrowing
In the asthma control test, what do the scores mean?
Out of 25:
25: Perfectly controlled asthma
20-24: Well controlled asthma
<20: Further treatment necessary
Steps of asthma therapy
- SABA alone
- SABA + ICS (low) (if need for maintenance is shown)
3.SABA + ICS (low)+ LRTA - SABA+ ICS (low)+ LRTA + LABA (review LRTA effectiveness)
- MART (with low ICS) +/- LRTA
- MART (with moderate ICS) +/- LRTA
- MART +/- LRTA (Or high ICS on fixed dose therapy)
Consider also LAMA and additional advice for step 7
What does it mean to have well controlled disease?
The patient should suffer from no symptoms during the day and should be able to carry out their regular activities without hindrance
What lifestyle messages should you aim to get across to asthma patients?
Understand the risks of uncontrolled asthma
Encourage to stay active and lose weight
They should know of their lung health and personal health plan
Recommend taking vaccines
Share info with each other about meds and devices
BTS/SIGN vs NICE guidance
Main difference are the tests done and the order of the drugs given
NICE is more cost effective
Assessing an acute exacerbation
ID the trigger factor
ID the type and duration of symptoms
ID the treatment started and if its working
Assess severity of exacerbation
Ask about depression, alcohol misuse, poor compliance, previous exacerbation.
Use these as a basis for deciding whether to admit to hospital
Assessing the severity of an exacerbation
Check for signs of exhaustion: cyanosis, SOB
Examine patient chest and record respiratory rate, pulse an BP
Check peak expiratory flow rate:
->50-75%=moderate
-33-50%=severe
-<33%=life threatening
Measure O2 sat. if possible
How can you manage acute exacerbations?
Give high O2 to maintain O2 sat at 94-98%
High dose SABA+ICS
IV Beta agonists for patient where inhalation not possible
Oral steroids in doses suitable for severity
IV magnesium sulfate for patients unresponsive to beta agonists
The 5 steps of the BTS/SIGN guidelines
- Low dose ICS
- LABA + ICS (usually as MART)
- -If LABA doesn’t work then stop LABA and increase ICS
- If LABA works but inadequate then increase LABA + continue ICS OR continue LABA+ICS and add LRTA - Increase to high dose ICS or add 4th drug eg LAMA
- Add in oral steroids at lowest adequate dose
What is difficult asthma?
Asthma patients suffering from symptoms even on steps 4/5 of BTS/SIGN guidelines and one of:
- life threatening exacerbation requiring invasive ventilation in the last 10 years
- daily dose of oral steroids >7.5mg daily
- 2 hospitilisations in last 12 months on high dose ICS
- FEV1 <70% of normal
Questions you should ask of difficult asthma patients?
Do they actually have asthma?
Are there conditions that are making the asthma worse?
These include:
Bronchostasis- abnormal widening of airways causing build up of sputum and causes infection
Dysfunctional breathing
Severe COPD
Vocal chord dysfunction
