Case 2 - Asthma Flashcards
What are the 3 major characteristics of asthma?
- Airflow obstruction
- Bronchial hyper-responsiveness
- Inflammation
What is the difference between atopic and non-atopic asthma?
- Atopic has allergic triggers, is extrinsic, usually develops in childhood and is a Type 1 hypersensitivity reaction
- Non-atopic usually develops later and is triggered by cold/exercise/virus
Which immunoglobulin is associated with asthma?
IgE
Which genetic factors can lead to asthma?
- Maternal smoking
- Intrauterine nutrition: hygiene hypothesis
- Specific genes – these increase the risk of developing asthma
- Family history of asthma
What environmental factors can lead to asthma?
- Hygiene hypothesis
- Excreta of house dust mites
- Pollens
- Exercise or emotion
- Cold air
- Respiratory tract infections
- Animal fur, dander, saliva
- Fungal spores
- Occupational factors
- Drugs (e.g. aspirin)
- Environmental pollutants
What is childhood asthma?
Asthma that is diagnosed before the age of 12 and is normally due to genetic predisposition
What is adult onset asthma?
Type 1 hypersensitivity reactions to certain allergens and is mainly due to environmental factors
What are the differentials for asthma?
- COPD
- PE
- Bronchitis
- Pneumonia
What are the symptoms of asthma?
- Chest tightness
- Dyspnoea – difficulty breathing
- Coughing
- Wheezing
- Sputum
- Diurnal variation
What type of wheeze is present in asthma?
- Polyphonic
- On expiration
Why is asthma diurnal?
– Symptoms are worse at night this is because cortisol (which is immunosuppressive) has diurnal variation.
- Less cortisol at night = less immunosuppression = more symptoms.
Which tests are done to diagnose asthma?
- Spirometry
- Peak expiratory flow rate
What peak expiratory flow rate results diagnose asthma?
PEFR varies by at least 20% for 3 days in a week
How to diagnose asthma?
- More than one of the symptoms of wheeze, breathlessness, chest tightness and cough
- Occurring in episodes
- No or minimal symptoms in-between
- Diurnal variation
- Personal history of atopic disorder (eczema)
What will asthma show as on spirometry?
- Obstructive picture
- Low FEV1
- Low FEV1/FVC ratio (below 70%)
- SABA bronchodilator reversibility
What additional tests are conducted in asthma?
- Allergy testing
- Sputum eosinophils (increased)
- Methacholine challenge (asthma trigger, inhalation leads to asthma attack)
How to manage asthma?
- Annual review
- Vaccination (pneumococcal, flu)
- Self monitor PEFR
- SABA
- Add low dose ICS
- Add LABA (consider before increasing steroid)
- Increase ICS or add LTRA (consider stopping LABA)
- Refer to specialist
What are the side effects of beta 2 agonists (salbutamol, salmeterol)?
- Tachycardia
- Tremor
- Hypokalaemia
- Dizziness
- Headache
- Arrhythmia
- Paradoxical bronchospasm
Which class of medication does montelukast belong to?
Leukotriene receptor antagonists
Which class of medications does ipratropium belong to?
Anti-muscarinics
What are the side effects of antimuscarinics (ipratropium)?
- Dry mouth
- Nausea
- Headache
Which class of medications does theophylline belong to?
Phosphodiesterase inhibitors
What are the side effects of PDE inhibitors (theophylline)?
- Tachycardia
- Arrhythmias
- Agitation
- Hypokalaemia
- Convulsions
What is a preventer inhaler?
- Glucocorticoids
- Once a day
