asthma and resp immunology Flashcards
why is there a wheeze in asthma
Reversible airflow obstruction
Airflow obstruction:
FEV1 / FVC ratio
for children and adults in asthma
<0.7 (adults)
<0.8 (children)
what is the pathogenesis of allergic asthma (type 1 hypersensitivity)
- allergens ie. pollen contact bronchial epithelium
- sensitise immune system
- remodelling of airway
- inflammation +eosinophils recruitment
- inflammatory mediators released
GWAS for asthma susceptibility- what is commonly seen
IL-33 and GSDMB
type 2 immunity in allergic asthma
- antigen
- MHC class II on APC
- Naive T cell (Th0)
- differentiate to Th1/Th2
5.Oesinophilic airway inflammation:
T-helper -2: IL-4, IL-5, IL-13
what does IL-4, IL-5, IL-13 do
IL-4,- activate B cells. Release IgE (bind to mast cells)
IL-5, increase eosinophil
IL-13, produce mucus
tests for allergic sensitisation
blood test- for specific IgE antibodies to allergens of interest
allergic skin prick test
test for eosinophilia
blood eosinophil count= 300cells/mcl+
induced sputum eosinophil= 3% +
exhaled NO
what a non-invasive biomarker of airway (type-2 eosinophilic) inflammation
and what can you use it for
FeNO- fraction of exhaled nitric oxide
asthma diagnosis, assessing adherence to inhaled corticosteroids
how to diagnose asthma in children
5-16y.o:
asthma symptom and:
spirometry: +ve peak flow variability and
FeNO= 35ppb+
or
obstructive spirometry (FEV1/FVC ratio <0.8) and
+ve bronchodilator reversibility (12%+)
how to diagnose asthma in adults
asthma symptom and:
spirometry: +ve peak flow variability,
+ve bronchodilator reversibility (12%+),
FeNO- 40ppb+
or obstructive spirometry (FEV1/FVC ratio <0.7)
basics- what is most important in asthma management
-Optimal device and technique
-Clear asthma management plan
-Adherence to inhaled corticosteroids
asthma treatment ladder for adults
suspected asthma: monitor + low dose ICS
diagnosed:
1. low-dose ICS (fixed or MART)
2. +inhaled LABA
3. increase ICS- medium dose or + LTRA
4. REFER to specialise care
consider moving up if using 3 dose a week or more
consider stopping LABA if no response to it
asthma treatment ladder for children
suspected asthma: monitor + very low dose ICS
diagnosed:
1. very low-dose ICS
(or LTRA <5y.o)
- +inhaled LABA/LTRA (5y.o+)
+ LTRA <5y.o - increase ICS- low dose or
+ LABA/LTRA (5y.o+) - REFER to specialise care
consider moving up if using 3 dose a week or more
consider stopping LABA if no response to it
how to improve adherence - SMART
SMART- single inhaler maintenance and reliever therapy
-single combo inhaler of ICS + quick acting LABA
-may need fixed maintenance dose.
-may reduce total ICS dose delivered
Pathogenesis of acute lung attack: school age children
-Reduced anti-viral responses
-reduced peak expiratory flow
-increase airway eosinophilic inflammation
Anti-IgE antibody medicine
who is it for and how to give the treatment
omalizumab
severe asthma 6+years.
OCS 4+ in last year
serum IgE 30-1500IU/ml
dosing based on weight and serum IgE 2-4 weeks s/c injections
Anti-IL5-antibody medicine
who is it for
Mepolizumab
-6y.o +
-severe eosinophil asthma
-blood eosinophil 300cells/mcl+ in last year.
-4+ OCS in last year
Dupilumab- what does it target and what it does
anti-IL4Rα Ab, shared receptor for IL-4 and IL-13
fewer asthma attacks and improve lung function
order of tests to perform in children with asthma symptoms
- spirometry
- bronchodilatory reversibiltiy if [1=obstructive]
if cannot-> clinical judgement//try again 6-12months
- uncertain after 1. 2.-> FeNO
- still uncertain = monitor peak flow variability 2-4 weeks
