Asthma Flashcards
What is asthma?
A chronic inflammatory disease of the large and small airways
What are the three main factors in asthma?
Reversible airflow obstruction
Airway inflammation
Airway hyper-responsiveness
What happens in airway remodelling?
Basement membrane thickens
Submucosa undergoes collagen deposition
Smooth muscle hypertrophy
What is the most important type of cell that is involved in asthma?
Eosinophils
Asthma is Th1 mediated, true or false?
False - Th2
What cells cause inflammation in asthma?
Mast cells
Eosinophils
Dendritic cells
Lymphocytes
What are some triggers of asthma?
Allergens (animals, dust, pollens, fungi) Exercise Viral infection Smoke Chemicals Drugs (NSAIDs, beta blockers)
What is the PEFR for moderate, severe and life-threatening asthma?
Moderate: 75-50%
Severe: 50-33%
Life-threatening: <33%
What are risk factors for asthma?
Family history of asthma or eczema
Exposure to allergens (dust lites, pets, tobacco smoke)
Recent upper respiratory tract infection
Workplace sensitisers
What are the symptoms of asthma?
Episodic attacks of breathlessness Non-productive cough (can be nocturnal) Chest tightness Wheeze Can be precipitated by triggers Worse at night and early morning
What are the signs of asthma?
Poor air entry
Expiratory wheeze
Nasal polyposis
What are investigations for asthma?
PEFR FEV1/FVC ratio ABGs Bloods - high eosinophils Trial salbutamol Challenge test - provocation testing for bronchospasm (exercise, histamine, methacholine, mannitol) Immunoassay for specific IgE Skin prick test Fractional exhaled nitric oxide
What do the following investigations show in asthma?
FEV1/FVC ratio
PEFR
FEV1/FVC ratio: <80% of predicted
PEFR decreased compared to normal for height and sex
Diurnal variability - lower in morning than afternoon
What are the common examples of ICS used for asthma maintenance?
Beclometasone
Butesonide
Fluticasone
What are some side affects of ICS?
Oral candidiasis
Stunted growth in children
Dysphonia (hoarse and weak voice)
What are the common examples of SABAs used for asthma relief?
Salbutamol
What is a side effect of SABAs?
Fine tremor
Tachycardia
Cardiac dysrhythmia
Hypokalaemia
What are the common examples of LABA used for asthma maintenance?
Salmeterol
Formoterol
What is the common LTRA?
Montelukast
What is an acute exacerbation of asthma?
An acute or subacute episode of progressive worsening of asthma symptoms
What are some triggers of an acute asthma attack?
Respiratory viruses
Allergen
Irritant
What are risk factors for an acute asthma attack?
Previous near-fatal asthma - requiring ventilation or respiratory acidosis Previous admission for asthma Requiring 3 or more classes of asthma medication Heavy use of SABA Inadequate use of ICS Incorrect inhaler technique Smoker Poor air quality GORD
What are the symptoms of an acute asthma attack?
History of asthma Bouts of dyspnoea and chest discomfort Nocturnal cough Wheeze Clear sputum if any and no haemoptysis
What are the signs of an acute asthma attack?
Short of breath at rest
Tachypnoea
Tachycardia
Diminished breath sounds
What investigations are done for an acute asthma attack?
Pulse oximetry
Peak flow
ABGs
ECG and CXR to exclude
What are the next treatments for an acute asthma attack after initial treatment?
Continue O2 at lower dose
Oral steroids
Nebulised salbutamol
Monitor peak flow and oxygen saturations
What does airway hyper-responsiveness mean?
The airway becomes twitchy and sensitive to stimuli that are breathed in
Can be either allergic or non-allergic
What causes the brief symptoms in asthma?
Bronchoconstriction
What does chronic airway inflammation cause in asthma?
Exacerbations
Airway hyper-responsiveness
What does airway remodelling lead to?
Fixed airway obstruction - irreversible
What are the clinical features of allergic asthma?
Childhood onset
Atopic triad: asthma, eczema, rhinitis
What are the specific treatments for allergic asthma?
Montelukast
Antihistamines
Allergen avoidance
Omalizumab (monoclonal antibody to IgE)
What are the clinical features of eosinophilic asthma?
Eosinophils >0.15 4+ exacerbations in the previous year Usually adult onset F>M More steroid resistant
What is the specific treatment for eosinophilic asthma?
Prednisolone
Mepolizumab or benralizumab (anti-Il-5)
Anti-allergen not effective
What investigations are done in all suspected asthma?
Spirometry - FEV1/FVC, PEFR
Trial salbutamol
What investigations can be done if intermediate suspicion of asthma?
Spirometry Bronchodilator reversibility PEF charting Challenge tests FeNO Blood eosinophils Skin prick test IgE
What is the treatment for asthma?
- Low dose ICS + SABA as required
- ICS + LABA + SABA as required
- if no response to LABA - stop LABA, increase ICS. If inadequate response to LABA - continue LABA, increase ICS. Consider trial of LRTA, theophylline, LAMA
- Increase ICS to high dose. Consider addition of 4th drug. Refer to specialist care
Can SABAs be given on their own?
No - always ICS
When should you move to the next step in asthma management?
If needing to use SABA 3x week or more
When should you consider decreasing maintenance therapy?
If controlled with current medication for at least 3 months
Only consider stopping ICS completely for people using low dose ICS alone and are symptom free
When should you refer someone with asthma to secondary care?
Diagnosis unclear
Suspected occupational asthma (symptoms better when not at work, adult onset, high risk occupations)
Severe/life threatening asthma attack
Red flags
What features in ‘asthma’ are red flags?
Prominent systemic features (myalgia, fever, weight loss)
Unexpected clinical findings (crackles, clubbing, cyanosis, cardiac disease, monophonic wheeze or stridor)
Persistent non-variable breathlessness
Chronic sputum production
Unexplained restrictive spirometry
CXR shadowing
Marked blood eosinophilia
What is the action of ICS?
Anti-inflammatory
Decrease immunological response
No bronchodilator effect
What is the action of SABAs in asthma?
Airway smooth muscle relaxation
Increase mucus clearance
Decrease mediator release from mast cells and monocytes
When is montelukast useful?
Allergic phenotypes
Exercise induced asthma
What are the side effects of montelukast?
Nightmares
What is he action of montelukast?
Bronchodilator
Smooth muscle relaxation
Decrease in mucus secretion and oedema
What is the example of LAMAs used most commonly in asthma?
Tiotropium
When is tiotropium useful in asthma?
To reduce exacerbations in severe patients
Breathless patients without allergy or inflammation
What is the action of theophylline?
Unclear
Relaxation of smooth muscle
Anti-inflammatory
What are the downsides of theophylline?
Doesn’t work in smokers
Side effect: nausea
When is theophylline used?
If nothing else works
What is a moderate severity asthma attack?
Increasing symptoms
PEF >50-75%
No features of severe
What is a severe asthma attack?
Any one of: PEF 33-50% Resp rate >25 Heart rate >110 Inability to complete sentences in one breath
What is a life-threatening asthma attack?
Any one of: Altered conscious level Exhaustion Arrhythmia Hypotension Cyanosis Silent chest Poor respiratory effort PEF <33% SpO2 <92 PaO2 <8 'Normal' PaCO2
What is the treatment for an acute asthma attack?
Oxygen - high dose by mask, maintain 94-98% sats
Salbutamol nebuliser with O2
Ipratropium bromide nebuliser
Steroids - increase ICS
Single dose magnesium sulphate for severe or poor response to salbutamol
Which signs in an asthma attack require referral to intensive care?
Deteriorating PEF
Persisting or worsening hypoxia
Hypercapnia
ABGs showing decreased pH or increased H+
Exhaustion, feeble respiration
Drowsiness, confusion, altered conscious state
Respiratory arrest
