13.1 Circadian biology of Asthma Flashcards
1
Q
What is the definition of asthma?
A
- Chronic inflammatory condition of the airways characterized by bronchial hypersensitivity to a variety of stimuli (triggers) leading to variable airway obstruction
- Day to day diurnal variability in symptoms
- Can be measured using peak expiratory flow rate (PEFR), is a person’s maximum speed of expiration
2
Q
What are the phenotypes of asthma?
A
- Cough-variant
- Eosinophilic
- Non eosinophilic
- LATE onset asthma
- NSAID related asthma
- Occupational
- Chronic asthma with fixed airflow obstruction
- Exercise induced bronchospasm
- Allergic asthma
- IgE mediated
3
Q
Explain the pathophysiology of asthma
A
- Best described as chronic eosinophilic bronchitis/bronchioloitis
- Airway inflammation with cellular infiltration by T helper 2 cells, lymphocytes, eosinophils and mast cells
- Cytokine production (platelet activating factor PAF)/ interluekins (including IL5) and leukotrienes
- Large and small airway involvement
- Airway inflammation with cellular infiltration by T helper 2 cells, lymphocytes, eosinophils and mast cells
- Resulting airway obstruction from:
- Inflammatory cell infiltration
- Mucus hypersecretion and plugging
- Smooth muscle contraction
- Can result in chronic and (sometimes) irreversible airway damage (through remodelling with smooth muscle hypertrophy/ hyperplasia)
4
Q
Draw the difference between a normal bronchiole and an asthmatic bronchiole
A
5
Q
What are the risk factors of asthma?
A
- Boys>Girls
- Women>Men
- Family history
6
Q
What are the common triggers of asthma?
A
- Weather
- Food
- Pollution
- Cigarette smoke
- Emotion/ stress
- Mould/ damp
- Pets
- Exercise
- Dust
- Pollen (e.g. this would be seasonal)
- Drugs including NSAIDs
- LRTi (lower respiratory tract infections)
- Viral respiratory illness (rhinovirus, influenza, RSV, parainfluenza, human metapneumovirus), sinus infections
7
Q
What is the difference in signs and symptoms between acute and chronic asthma?
A
-
ACUTE
- SOB
- Cough +/- green phlegm (meaning INCREASE in neutrophils in sputum thus, inflammatory)
- Chest pain/ tightness
- Difficulty completing sentences
- Wheeze
-
CHRONIC
- Coughing and wheezing are the most common symptoms of childhood Asthma
- Breathlessness, chest tightness or pressure, and chest pain also are reported
- Poor school performance and fatigue may indicate sleep deprivation from nocturnal symptoms
8
Q
What are some symptoms of life-threatening asthma?
A
- Cyanosis
- Arrythmia
- Hypotension
- Altered conscious level
- Exhaustion
9
Q
What are some symptoms of near-fatal asthma?
A
- Raised PaCO2
- Required mechanical ventilation with raised inflation pressures
10
Q
What are good questions to ask in an asthma history?
A
- How many times a week do you use SABA
- What are your triggers/ Pets
- How many courses of steroids in the last year
- How often do you forget to use your inhalers
- Smoking status
- Job
- Exercise
- Anxiety element
- “Vocal hygiene”
11
Q
What are the markers of a poor prognosis (treatment) of astma?
A
- Poor adherence
- Previous acute admissions and/or intubation
- 3+ different classes of asthma medication
- Psychosocial dysfunction
- Inadequately treated disease
- Smoking
12
Q
On a respiratory examination how can you tell someone has asthma?
A
- Wheezing is a high-pitched, expiratory sound produced when air forced through narrow airways
- Asthma wheeze tends to be polyphonic (varied in pitch)
-
ACUTELY
- May have low oxygen levels
- High respiratory rate/ other visible signs of respiratory distress
- PEFR (peak expiratory flow rate) tends to go down
13
Q
What are the differential diagnosis of asthma?
A
- COPD – fixed airflow obstruction
- Upper airway obstruction (stridor)
- Inducible laryngeal obstruction
- Foreign body
- Hyperventilation syndrome
- Pattern of breathing where you breathe more quickly and deeply than normal
- Causes INCREASE CO2 levels in blood
- Pattern of breathing where you breathe more quickly and deeply than normal
- Anxiety
- Gastro-oesophageal syndrome
- Pulmonary oedema
- Eosinophilic vasculitis
- A family of rare diseases characterized by inflammation of the blood vessels, which can restrict blood flow and damage vital organs and tissues
- Respiratory bronchiolitis
- Common lung infection in young children and infants. It causes inflammation and congestion in the small airways (bronchioles) of the lung
- Interstitial lung disease
- Pulmonary Hypertension
14
Q
Explain diagnosis of Inducible laryngeal obstruction
A
- Also, on flow-volume loop inspiration flow is much less than normal
- Can be characterised by inspiratory noise
15
Q
What investigations should be done with someone with asthma?
A
-
PEFR variability
- Twice daily 2-4 weeks
- +ve if >20% variability
-
Spirometry
- FEV1/FVC ratio <70%
- 400ml/ 20% increase in FEV1 after SABA
-
FeNO
- Marker of eosinophilic inflammation (IL-4/IL-13 mediated)
- +ve if >40
-
Bronchial provocation
- Inhalation of noxious stimulant results in a drop in FEV1 of 20%
17
Q
Explain the pharmacological steps with someone with asthma (getting worse)
A
20
Q
What is the mechanism of action or oral/inhaled corticosteroids?
A
23
Q
Explain the mechanism of action of omalizumab
A
25
Q
Explain the mechanism of action of dupilumab
A
- Is a fully human monoclonal antibody that BLOCKS shared receptor component for IL-4/IL-13 (prevent Th2 binding to it)
- Causes a decrease in:…
27
Q
How can we make sure asthma patient’s are getting ongoing care?
A
- Self management plans (shown in picture has traffic light system)
- Patient education
- Use of apps/ telemedicine
- Annual GP review
- Practice/ Asthma Nurse
- Secondary care review for more advanced cases
