Asthma Flashcards
What is asthma?
Chronic inflammatory disorder of the airway secondary to type 1 hypersensitivity
Typically develops in childhood and symptoms typically resolve with age.
What are common risk factors for developing asthma?
- Personal or family history of atopy
- Antenatal factors (maternal smoking, viral infection)
- Low birth weight
- Not being breastfed
- Maternal smoking around children
- High concentration of allergens (e.g. dust mites)
- Air pollution
- Hygiene hypothesis
- Occupational asthma in adults
Triad of other IgE-mediated atopic conditions includes atopic dermatitis and allergic rhinitis.
What are the typical symptoms of asthma?
- Cough (worse at night)
- Dyspnoea
- Wheeze
- Chest tightness
Symptoms can vary in severity and may change with age.
What are the signs of asthma during examination?
- Expiratory wheeze on auscultation
- Reduced peak expiratory flow rate (PEFR)
Auscultation is a key part of the physical examination for asthma.
What is the purpose of spirometry in asthma diagnosis?
Categorises respiratory disease as obstructive or restrictive
Measures FEV1 and FVC to assess lung function.
What does FEV1 stand for and what does it measure?
Forced expiratory volume in 1 second; volume of air that can be exhaled as ‘hard + fast’ in 1 second
A significant reduction in FEV1 is indicative of asthma.
What does FVC stand for and what does it measure?
Forced vital capacity; maximum volume that can be exhaled following full inspiration
In asthma, FVC is typically normal.
What is the FEV1% threshold for asthma diagnosis?
FEV1/FVC < 70%
This indicates obstructive lung disease.
What does a high level of fractional exhaled nitric oxide (FeNO) indicate?
Increased inflammation in asthma (50ppb+ = asthma)
Adults:** FeNO ≥ 50ppb;** Children: FeNO ≤ 35ppb indicates asthma diagnosis.
Typcially spirometry findings in asthma
- FEV-1 - significantly reduced
- FVC - normal
- FEV1% (FEV1/FVC) < 70%
What is the significance of eosinophils in asthma?
Direct marker for airway inflammation
Eosinophil count above 0.4 x 10⁹/L is indicative of asthma.
What is the typical management approach for adults and children with asthma?
- 1st line: Low dose ICS/formoterol inhaler
- 2nd line: Low-dose MART (ICS/formoterol)
- 3rd line: Moderate-dose MART
- 4th line: Check eosinophil and FeNO
- 5th line: Refer to specialist
MART stands for maintenance and reliever therapy.
Asthma management - 1st line
1st:
* Anti-inflamatorry reliever (AIR): Low dose ICS/formoterol (LABA) inhaler
* OR w/ highly symptomatic patients: low-dose MART
** MART = maintenance and reliever therapy: ICS + fast-acting LABA (formoterol)**
What is a MART?
MART = maintenance and reliever therapy: ICS + fast-acting LABA (formoterol)
Asthma management - 2nd line
- Low-dose MART (ICS/formoterol)
Asthma Management - 3rd line
- Moderate-dose MART
Asthma management - 4th line + test
4th:
* Check eosinophil and FeNO
* If raised: refer to specialist care
- If normal but asthma still not controlled: Moderate-dose MART + (LTRA or LAMA) for 8-12 week trial
- If still not controlled: Try ‘other’ one of LTRA or LAMA
What is the role of stepping down treatment in asthma management?
Consider stepping down every 3 months by reducing inhaled steroid by 25-50% at a time
This helps to find the lowest effective dose.
What are common occupational asthma exposures?
** Isocyanates**
* Soldering flux resin
* Glutaraldehyde
* Flour
* Epoxy resins
* Proteolytic enzymes
Occupational asthma often presents with symptoms that worsen at work and improve on weekends.
True or False: A peak flow diary can be useful in diagnosing occupational asthma.
True
Monitoring peak flow at work and home can help identify triggers.
Fill in the blank: The hygiene hypothesis suggests that reduced exposure to _______ in childhood prevents normal immune development.
infectious agents
This theory relates to the development of asthma and allergies.
What is ghe use of peak flow in asthma?
- Can reflect diurnal changes
- +ve asthma if there is a >20% variation in PEF between morning and evening values, supports the diagnosis of asthma and highlights its dynamic, reversible nature.
