Asthma in Adults Flashcards
FEV1/FVC ratio?
Obstructive - so decrease
Pathology
Inflammatory condition characterised by bronchoconstriction by smooth muscle contraction and airway oedema (mucus)
Reversible
Aetiology
Passive smoking
Maternal smoking - lungs don’t develop
Air pollution
Occupation - jobs exposing to dust, vapours, fumes
Airway hyper responsiveness - Type 1 hypersensitivity
Symptoms
SOB Wheeze Cough Chest tightness Diurnal variability - timing Episodic Atopy
Signs
Tachypnoea Wheeze Eczema Response to bronchodilators Peak flow returns to normal (reversible) Obstructed spirometry
Useful Investigations
CXR (hyperinflation, hyperlucent)
Skin prick test to measure serum IgE (assess atopy)
FBC (eosinophilia - atopy)
U+Es (renal function)
Aims of treatment
No day/night symptoms No need for rescue meds No asthma attack (Exacerbation) Normal lung function (no limitations) FEV1 or PEF > 80% Minimal side effects
Non pharmacological management
Exercise
Smoking cessation
Weight management
Flu/pneumococcal vaccines
Pharmacological management
Inhaled short acting B agonist - reliever Inhaled corticosteroid (ICS) Inhaled LABA
Add on:
Leukotriene receptor antagonists
Theophyllines
Oral steroids
Benefits of inhalers
Small dose Delivered straight to airways and lungs Onset of effect faster Low systemic exposure Side effects less severe and less frequent
When to escalate treatment
If there is no response to inhaled LABA - stop LABA and increase dose of ICF
If benefit from LABA but control by patient is inadequate - continue LABA and increase ICS to medium dose. If still inadequate then consider trial of other therapy
Acute asthma sign
Can they complete sentence before breathlessness?
Hunch forward and shoulders raised to increase vol. into lungs
Wheezy, cough
How to prevent acute asthma attack
Patient specific Know trigger (patients know their action plan and their signs) Avoid delays Follow guidelines
Asthma attack features
PEF 33-50% of normal
RR > 25
HH > 110
Cant finish sentence in one breath
What cause the narrowing of the airways?
Airway inflammation mediated by immune system cause bronchoconstriction, and releases ACh, histamine and leukotrienes from mast cells, eosinophils and macrophages and asthmatics usually have increased airway reactivity causing further narrowing
Risk factors
Genetic - atopy
Occupation
Smoking - decrease FEV1 and increase airway responsiveness
Describe the genetic factors in the risk of developing asthma
Genetic tendency for IgE to respond to allergens
Immune response genes: IL-4 / 5, IgE
Airway gene: ADAM33
3x more likely to develop if mother has atopy
What to look for in clinical history
PMH:
Childhood asthma, bronchitis
Hayfever
Drugs:
Current inhalers, check technique and compliance
B-blockers, aspirin, NSAIDs
FMH:
Atopic disease
PSH:
Smoking
Pets
Occupation
Interpretation of spirometry
FEV/FVC ratio <70%
FEV1 < 80% predicted
Use of PEF
Lung function in clinic may be normal, PEF used to look for variability in airflow obstruction
Peak flow meter and chart, twice daily for 2 weeks
Look for:
Morning/nocturnal dips
Decline over weeks/days
Variability > 20%
Can diagnose occupation asthma (lowest PEF during weekdays)
What are the main investigations?
Spirometry
Pulmonary function test (to look for COPD)
Reversibility
PEF - if spirometry is normal
Sign of life threatening acute severe asthma
Grunting Impaired consciousness, confusion, exhaustion HR > 130 or bradycardic Hypoventilating PEF < 33% best Cyanosis
Sao2 < 92% (no ventilation)
PaO2 < 60mmHg
PaCO2 normal
Sign of asthma attack (fatal)
Raised PaCO2
Step 1 in treatment
Start on inhaled short acting B2 agonist - relievers
Salbutamol (MDI, DPI)
Terbutaline (DPI)
Step 2 in treatment of adults
Add low-dose ICS (200-800mg) - preventer
Step 3 (add on therapies) in treatment of adults
Add inhaled long acting B2 agonist to ICS
In step 3, what happens if there is no response to LABA?
Stop LABA and increase dose of ICS to 800mg
Step 4 of treatment in adults
Consider trials of:
Increasing ICS to 2000mg
Addition of fourth drug - LTRA, theophylline, beta agonist tablet, LAMA
Step 5 of treatment in adults
Use daily steroid TABLET
Maintain high dose of ICS
May refer patient to specialist
Three oral therapies
Leukotriene receptor antagonist
Theophylline
Prednisolone
Use of ICS criteria
If using inhaled B2 agonist > x3 a week
Waking 1 night a week
Sub-normal exercise tolerance
Specialist options for treatment
Omalizumab (anti-IgE)
Mepolizumab (anti-interleukin-5)
Bronchial thermoplasty
Response to mild/moderate acute asthma attack
Increase inhaler use Oral steroid Treat trigger Early follow up plan Back up plan
Response to sever acute asthma attack
HOSPITAL Nebulisers - salbutamol, ipratroprium Oral/IV steroid Magnesium (helps bronchoconstriction) Aminophylline Know triggers - infection/allergen Complication - do CXR
Benefit of inhalers over oral therapy
Direct delivery to target organ (airway and lungs)
Onset of effect faster
Minimal systemic exposure (adverse effect less)
What is a pMDI?
Metered dose inhalers:
Delivers specific dose of drug by aerosol
Advantages and disadvantages of pMDIs
Doesn’t require deep breath (low inspiratory flow)
But requires coordination for simultaneous push and inspiration - no effective for young and elderly
What is a DPI?
Dry powder inhaler:
Requires high inspiratory flow
Less coordination required
What can occupation expose a person to which would increase risk of developing asthma?
Isocyanates (paint)
Grains
Enzymes
Crustaceans
Describe the effect of maternal smoking during pregnancy in asthma
Nicotine causes modification in oocyte in female foetus’
Decrease FEV1
Increase wheeze
Increase airway response
Increase asthma and severity
What is the ‘grandmother’ effect of asthma risk?
Mother smoked: 50% chance of developing
Maternal grandmother smoked: 150%
Mother and maternal smoked: increased further
What are conditions that cause general airflow obstruction?
Asthma (reversible AFO) COPD (irreversible AFO) Bronchiectasis Bronchiolitis CF
What is investigated in pulmonary lung function tests?
Lung volumes:
Increase residual volume
Increase total lung capacity
RV/TLC > 3-%
CO Gas Transfer
How do you intemperate reversibility to bronchodilator investigation?
Baseline and then 15mins post salbutamol
Significant reversibility: FEV1 >200ml and FEV1 > 15% of baseline
What are the steps in investigations if spirometry is obstructed?
- Spirometry = obstructed
- Pulmonary function test
- Reversibility to bronchodilators
- Reversibility to corticosteroids
How is reversibility to corticosteroids investigation carried out?
0.6mg/kg Predinisolone for 2 weeks
Peak flow chart and meter
Baseline and 2 week spirometry
What are the steps in investigation if the spirometry is normal?
- Spirometry = normal
- Peak flow meter and chart, twice a day for 2 weeks
- ‘Optional’ investigation for SPECIALIST - airway responsiveness to histamine/exercise and exhaled nitric oxide (FeNO)
What can a CXR show in asthma?
Hyperinflated
Hyperlucent
(No effusion, collapse, opacities, interstitial changes)
