Asthma Flashcards
What is asthma?
Asthma is a chronic inflammatory disease characterised by reversible airway obstruction
-Initial trigger releases inflammatory mediators
Lumen is reversibly folded due to smooth muscle bronchoconstriction and mucous hypersecretion
What are the cardinal features of asthma?
Atopy/Allergen sensitization
Reversible airflow obstruction
Airway inflammation
Eosinophilia
Type 2 lymphocytes
Wheeze/+- dry cough on exertion worse with colds and allergen exposure
What type of immune reaction is associated with asthma?
Type 2 immunity in allergic asthma
What cytokines are released in Asthma?
- IL-4 is a prominent immune mediator that supports the activation of B-cells into plasma cells to release IgE.
- IL-5 – Responsible for the maturation and release of eosinophils in the bone marrow.
- IL-15 is a central regulator in IgE synthesis, goblet cell hyperplasia, mucous hypersecretion, and airway hyperresponsiveness.
What roles does IL-5 have in asthma?
Maturation and releases of eosinophils in the bone marrow
What does role does IL-4 have in asthma?
A prominent lumen mediator that supports the activation of B-cells into plasma cells to release IgE
What effect does IgE have in asthma?
Mast-cell degranulation leading to the release of histamines and cytokines
What blood test is used to test for allergic sensitiation?
Blood test for specific IgE antibodies to allergens
only do once asthma diagnosis is confirmed
What are the risk factors for asthma?
Family history
Atopy (Tendency for T lymphocytes to drive production of IgE exposure
What environmental factors are associated with asthma?
- House dust mites
- Pollen
- Pets
- Cigarette smoke
- Viral respiratory tract infections
- Aspergillus fugimatus spores
- Occupational allergens
What is the presentation of asthma?
- Intermittent dyspnoea (SOB)
- polyphonic expiratory wheeze
- Cough (worse in the early morning and at night) + sputum. DIURNAL pattern of symptoms.
- Nasal polyposis
When is the asthma cough worse during the day?
Worse in early morning and at night
What is the pattern of symptoms for asthma?
Diurnal
What are the precipitating factors for asthma?
• Cold air – Induced bronchospasm
• Viral infection
• Drugs (E.g., beta-blockers, NSAIDs)
• Exercise
• Emotions
• Allergens – House dust mite, pollen, fur, pets – query.
• Smoking/passive smoking
• Pollution
• Ask if symptoms remit at weekend – may be triggered at work.
N.B: Check for history of atopic disease (Allergic rhinitis, urticaria, eczema).
What are the examination findings for asthma?
- Tachypnoea
- Use of accessory muscles
- Prolonged expiratory phase
- Polyphonic expiratory wheeze
- Reduced air entry
- nasal polyps
in acute asthma attacks –> Hyperinflated chest and hyper-resonant percussion notes
What defines a moderate asthma attack for PEFR?
PEFR > 50-75% predicted.
What parameters are associated with a severe asthma attack?
- PEFR 35-50% predicted
- Pulse > 110/min
- RR > 25/min
- Inability to complete sentences.
what parameters are associated with a near fatal asthma attack?
What parameters are associated with a life-threatening asthma attack?
- PEFR < 33% predicted
- Silent chest
- Cyanosis – PaO2 < 8 kPa, normal/high PaCO2 > 4.6 kPa, low pH <7.35.
- Bradycardia
- Hypotension
- Confusion
- Coma
What investigations are performed for the diagnosis of asthma?
Spirometry:
FEV1/FVC ratio <70% indicates airway obstruction
Bronchodilator reversibility (BDR) test is an imrpovement in FEV1 of 12% or more
Fractional exhaled nitric oxide (FeNO) - indicator of airway eosionphilia (but can be raised in conditions other than asthma)
Peak flow variability - diurnal variation in peak expiratory flow above 20%
(obstructive spirometry –> BDR –> FeNO –> asthma diagnosis)
What does a FeNO test reveal in asthma?
Confirm eosinophilic airway inflammation to support an asthma diagnosis in patients
above 40ppb in adults
above 35 ppb in children
What does a FeNO test reveal in asthma for adults?
above 40 ppb
What does a FeNo test reveal in asthma for children?
above 35 ppb
What does a FeNo indicate in a patient with diagnosed asthma?
A non-invasive biomarker of the airway (Type-2 inflammation) – can be used to determine adherence and steroid response.
An elevation in NO is indicative that the asthma is not adequately controlled or unresponsive to steroids.
What does a spirometer with a bronchodilator reversibility test reveal?
Defined improvement >12% in FEV1
offered to adults with <70% FEv1/FVC ratio to confirm asthma diagnosis
What is the defined improvement with the administration of a bronchodilator in asthma?
> 12%
What does an FBC reveal in asthma?
Eosinophillia
(in acute asthma attacks bloods can show reason precipitating attack e.g. neutrophilia in infection or raised CRP if severe infection)
What spirometry findings are associated with asthma FEV1/FVC?
FEV1/FVC <70% with bronchodilator reversibility
Which cells are implicated in the pathophysiology of asthma?
Mast cells and basophils
IgE mast cell degranulations
Eosinophil
What is the four pathophysiology steps in asthma?
Epithelial airway damage
Vascular smooth muscle hypertrophy
Airway hyperesponsiveness
Mucous plugging
Reversible airway obstruction with intact lung parenchyma
What is the presenting complaint for asthma?
SOB
Dry cough
Chest tightness
Variability of symptoms
Diurnal - worse at night + early in morning
Wheeze
Atopic disorders (Food allergies, eczema and hayfever)
When are asthma symptoms worse during the day?
During the night + early in morning
What is the triad of atopy (asthma)?
Hay fever
Food allergy
Eczema
Which conditions make asthma worse?
GORD - reflux exacerbates asthma
What questions asked for suspected asthma?
Are the problems always there?
Do you wake up at night breathless or coughing?
Are there noises when they breath?
Any triggers? Dusty environment, pets, smoking, exercise
Previous hospital admission and care?
What test is used to assess asthma control?
Asthma control test (ACT)
What is the FEV1/FVC ratio or asthma?
<70%
What two investigations are indicated for the diagnosis of asthma?
FeNO
Spirometry - FEV1/FVC <70% with bronchodilator reversibility >12%
What is the first-line management for asthma?
Salbutamol (SABA)
Address triggers, smoking cessation inhaler technique + adherence
What colour is a reliever inhaler?
Reliever- SABA -Blue
What colour is a preventor inhaler?
Brown - Low dose ICS
What are the management aims of asthma treatment?
what happens when these are not met?
No daytime symptoms or night time waking due to asthma
No asthma attacks or need for rescue medications
No limitations on activity
Normal lung function
Minimal side effects
escalate treatment to the next step above when symptoms are not adequately controlled
but use the lowest dose of ICS possible
make sure patient is trained in correct inhaler technique and confirm compliance
What medication is added if Low Dose ICS and SABA is unresponsive in asthma?
Long acting beta 2 agonist (LABA)
name leukotriene receptor anatagonist example
montelukast
Name an ICS?
beclometasone, budesonide, ciclesonide, fluticasone, and mometasone
Name a LABA
salmeterol
formoterol
Name a SAMA
ipratropium bromide
tiotropium,
What is the step-up management despite the use of LABA
Add Leukotriene receptor antagonist or increase ICS dose
What is the management for an acute exacerbation of asthma?
Oxygen
Salbutamol - 5mg nebulised, repeat 15-30mins
Prednisolone - 40-50mg oral
if poor initial response to SABA or acute severe or life-threatening asthma
Ipratropium bromide - 0.5mg, nebulised
(if no improvement then escalate to senior help)
acute severe asthma + had poor initial response to SABA
Magnesium sulphate - IV
Last resort by senior doctors:
Aminophylline - IV
ITU intubation + ventilation
what are the inhaler colours
blue –> SABA (Reliever)
brown –> ICS (preventer)
other colours are generally combinations see: https://ggcmedicines.org.uk/media/uploads/prescribing_resources/inhaler_id_chart_-_1701.pdf
note: MART is maintenance + reliever therapy which is ICS + LABA in a single inhaler
