Asthma Flashcards
What percentage of asthma patients does spirometry confirm obstruction in?
16-39% of patients, only bronchodilator reversibility in 15-17% of patients.
In contrast those admitted to hospital with asthma attack 83% have obstructive lung function
What are the spirometric values that diagnose bronchodilator reversibility ?
Improvement in FEV1 >12% and 200ml (in response to Beta-Agonist / corticosteroid treatment
Improvement > 400 ml strongly suggestive of asthma
What makes a good peak flow assessment ?
3 forced expiratory blows with a maximum pause of 2 seconds before blowing and further blows should be done if peak flows not within 40 l/min of each other
During direct challenge tests what is considered a positive test ?
The provocation concentration (PC20) required to cause a 20 % fall in FEV1 .
A PC20 of ≤ 8mg/ml is considered a positive test
NB if patients have established air flow obstruction challenge tests have little value
What is the false -ve rate of metacholamine test ?
<10%
Who should be referred for challenge tests ?
Consider in adults where there is no evidence of obstruction in spirometry and objective tests are inconclusive but asthma diagnosis remains a possibility
Talk about indirect challenge tests
Indirect challenges such as exercise and inhaled mannitol. A positive response to these indirect stimuli such as fall in FEV1 > 15% is a specific marker of asthma but the tests are less sensitive than challenges using histamine and metacholine particularly in patients tested whilst on treatment
What does a positive FeNO test suggest ?
A positive FeNO test suggest eosinophilic inflammation and provides supportive but not conclusive evidence of asthma
What increases FeNO levels ?
- Allergic rhinitis (even if exposed to allergen without symptoms)
- Rhinovirus infection
- Men
- Tall ppl
- Intake of dietary nitrates
What decreases FeNO levels?
- Smoking
- Being a child
- Inhaled or oral corticosteroids
What is a positive FeNO?
In steroid naive adults > 40ppb considered positive
BUT
1 in 5 with positive FeNO won’t have asthma
1 in 5 with negative FeNO will have asthma
What are the components of an asthma review?
Current symptom control
Future risk of attack
Tests/Investigations
Management
Supported self management
What are the validated and non validated questionnaires in asthma ?
VALIDATED :
*ACQ (Asthma Control Questionnaire) - reviews last 1 week of sx
*ACT (Asthma Control Test) - reviews last 4 weeks of symptoms
*Mini Asthma quality of life Questionnaire
NON VALIDATED
RCP 3Qs - 1 Have you had difficulty sleeping bc of your asthma sx? 2. Have you had your usual asthma sx during day ? (Cough, wheeze , tightness of chest , breathlessness) 3. Has your asthma interfered with your usual actions ?
What greatly increases your risk of future asthma attacks ?
Previous asthma attacks
What moderately increases your risk of asthma attacks ?
Poor control (assess with ACT /ACQ)
Inappropriate or XS SABA use
What slightly increases your risk of asthma attack?
Old age, female , reduced lung function, obesity, smoking , depression
What do we classify as severe asthma?
More than 2 asthma attacks a year or persistent symptoms with SABA use more than twice a week despite specialist level therapy
What does the personalised asthma action plan do?
Reduced emergency use of healthcare resources including ED , hospital admissions and unscheduled visits
Improved markers of asthma control decreasing symptoms and days off work and improving QOL
What are the PAAPs suggested action points ?
PEFR <80% : Quadruple ICS
PEFR <60% : Commence oral steroids and get same day medical review
PEFR <50% : Urgent medical review
**NB with increasing the ICS , from studies may be that those who are fully adherent have little to gain and the perceived benefits are in the group who have poor usage prior to starting
What is the NICE-BTS asthma management recommendation for stable asthma
Regular Preventer (Low dose - ICS)
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Initial add on therapy (Add inhaled LABA to low dose ICS , fixed dose or MART)
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Additional controller therapies (Increasing ICS to medium dose or adding LTRA). If no response to LABA consider stopping
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Specialist therapies
What is the aim of asthma management ?
Complete control of symptoms:
- no daytime sx
- no nighttime sx
- no need for rescue medication
- no asthma attacks
- no limitation on activity
- normal lung function
- minimal side effects for medications
Who should receive ICS?
Anyone who:
- has had asthma attack in last 2 years
- using B agonist X3 per week or more
- symptomatic x3 per week or more
- waking one night a week
*Start patients on steroid dose appropriate to their disease severity , mild to moderate confers no benefit giving higher dose
What dose regimen of ICS most effective ?
Twice a day
What does adding LABA therapy do?
Improves lung function, symptoms and decreases asthma attacks.
LABA should not be used without ICS