28 - Asthma Flashcards
3 features of asthma
Hypertrophy of airway wall muscle
Increased mucous production
Inflammatory cell infiltration
What is the prevalence of Asthma in children and adults
20 % prevalence in children
15 % prevalence in adults
What cells do allergens activate in an asthmatic
Th2 cells
What IL are B cells activated by and what do B cells produce
IL4
IL13
produce IgE
What cells does IgE activate
Mast Cells
What does mast cells release
Histamine
Prostaglandins
LTC4
Kinins
What do the mediators do
activate nerve endings, make mucus, airway wall oedema and bronchodilation
What happens to the FEV1/FVC ratio after an asthma attack
Decreases as FEV1 decreases but FVC is the same
What is the response to bronchodilators in asthma
Increase in FEV1 - reversibility of obstruction (characteristic of Asthma)
What is challenge testing
Use PEFR over time and environment to observe if the history is correct
Why can exercise not be good for asthmatics
Increases ventilation
Causes cooling and spasm
What can untreated asthma lead to
Bronchitis
COPD
What is the treatment for asthma
- 1 – Salbutamol
- 2 – Regular inhaled steroids
- 3 – + Long acting bronchodilators + increase inhaled steroids, consider leukotriene antagonists
- 4 – Theophyllines, leukotriene antagonists, anticholinergics
- 5 – Oral steroids, review diagnosis, consider anti IgE therapy, steroid sparing agents, statins/anti inflammatory agents, thermoplasty, anti-IL5 and anti IL4 receptor treatment
How does smoking affect asthmatics
- Causes oxidative stress by increasing NF Kb
* Blocks steroid response by HDAC2 – activated by theophyllines
