Asthma Flashcards
What is asthma characterised by?
Increased responsiveness of the trachea and bronchi to various stimuli and manifested by a widespread narrowing of the airways that changes in severity either spontaneously or as a result of therapy
Is bronchitis common?
Yes
Presentation of bronchitis
Loose rattly cough
Noisy breathing
Post tussive vomit (glut)
What is pertussis also known as?
Whooping cough
Pathology of bacterial bronchitis
Disturbed mucociliary clearance
Secondary infection following URTI
Causes of bronchitis
RSV
Adenovirus
Rhinovirus
Haemophilus
Pathology of asthma
Blocked airways because of mucus (luminal secretions) Increased irritability Bronchoconstriction Airway wall thickening Spontaneous or stimuli
Risk factors for asthma
Genetic
Occupation (painters, welding, labs, grains, bakers, antibiotics, salbutamol, crustaceans)
Smoking
Maternal smoking during pregnancy
Possible risk factors for asthma
Obesity
Diet
Reduced exposure to microbes/microbial products
Indoor pollution; chemical household products (volatile organic compounds, formaldehyde, fragrances, cleaning products)
Environmental allergens linked to asthma
House dust mite
Cats
Grass pollen
What is genetic atopy?
Inherited tendency to IgE response to allegens
Examples of atopy
Asthma
Eczema
Hay fever
Food allergy
What % of adult onset asthma is caused by occupation?
10-15%
What is higher BMI associated with in asthma?
Asthma
Wheezing
Airway hyperactivity
What is the allergen of house dust mite?
Protease in droppings
Types of onset of asthma
Infant onset Childhood onset Adult onset Exertional asthma Occupational asthma
Triggers of asthmatic symptoms
URTI (Rhinovirus in 75%) Exercise Allergen Cold air Emotion Menstruation Aspirin
What must be present for asthma to be diagnosed?
Wheeze
What children have asthma?
10 - 15%
M > F
What adults have asthma?
5 - 10%
F > M
What conditions can cause generalised airflow obstruction?
Asthma (reversible) COPD (irreversible) Bronchiectasis Bronchiolitis CF
Presentation of asthma
Wheeze
SOB at rest
Cough
Chest tightness/pain
Features of cough in asthma
Dry
Nocturnal
Exertional
Occasional sputum
What kind of symptoms must be present to diagnose asthma?
VARIABLE symptoms
- triggers
- daily variation (early morning/nocturnal)
- Weekly variation (occupation, better at weekends and holidays)
- annual (environmental holidays)
When is asthma generally worse?
Morning
Night
PMH associations of asthma
Childhood asthma
Eczema
Hayfever
Drugs associated with asthma
Aspirin
Complicance B blockers
NSAIDs
What would you ask about FH of asthma?
Atopic disease
Asthma
What social history would be associated with asthma?
Smoking
Pets
Occupation
Psychosocial
Possible signs of asthma
Breathlessness on exertion
Hyperexpanded chest
Polyphonic wheezes
What would a dull percussion note on examination indicate?
Lobar collapse
Effusion
What would crepitations on examination indicate?
Bronchiectasis
CF
Alveolitis
LVF
What is used in clinic to asses lung function in asthma?
Spirometry
How does spirometry work?
Deep breath in and blow out hard and fast
Best of 3 readings
Compare off chart
What is FEV1?
Forced expiratory volume in 1 second
What does FEV1 essentially measure?
Airway diameter
What does FVC essentially measure?
Lung capacity
If there is an obstructed picture, what should be done and what is involved?
Full pulmonary function testing - Helium dilution - CO gas transfer Reversibility to bronchodilator Reversibility to oral corticosteriods
Interpretation of reversibility to bronchodilator
15 mins post 400ug inhaled salbutamol
15 mins post neb 2.5-5mg salbutamol
Significant reversibility; difference in FEV 1 > 200ml and change in FEV1 > 15% baseline
What could cause no reversibility?
No bronchoconstriction
Severe bronchoconstriction
What does response to oral steroids separate asthma from?
COPD
What variability is present in asthma?
Morning/nocturnal dips
Decline over weeks/days
Variability >20% / highest
Diagnosis of occupational asthma
Suspicion from work related symptoms
Working with recognised occupational sensitizer
Serial peak flow readings (2 hourly best; 5 per day minimum)
Antibodies
+ve response to colophony
Useful investigations in asthma
CXR - hyperinflated - hyperlucent Skin prick testing (atopic status) Total and specific IgE (atopic status) FBC - eosinophilia (atopy)
Differential diagnosis for asthma
Viral induced wheeze Foreign body CF Immune deficiency Ciliary dyskinesia Tracheo-bronchomalacia Aspiration, GORD
What is anatomical space?
The air found in the conducting airways
What is alveolar dead space?
Air in the alveoli who has been ventilated but not perfused
What is physiological dead space?
Anatomical dead space plus alveolar dead space
Obs of moderate asthma
Increasing symptoms - no features of severe Able to speak complete sentences HR < 110 RR < 25 PEF 50 - 75% predicted or best Sa02 > 95% (No need for ABG) Pa02 > 8kPa
Features of severe asthma; any one of…..
Unable to speak, unable to complete sentences HR > 110 RR > 25 PEF 33-50% predicted or best Sa02 >92% Pa02 > 8kPa
Features of life threatening asthma; any one of….
Grunting Impaired consciousness, confusion, exhaustion HR >130 or bradycardic Hypoventilating PEF < 33% predicted or best Cyanosis Sa02 < 92% Pa02 <8kPa PaCO2 normal (4.6 - 6.0kPa)
What indicates near fatal asthma?
Raised PaCO2
If in doubt of asthma, what can be done?
Blood gas
When is it unlikely to be asthma?
Under 18 months (most likely infection) Isolated coughs - Bronchitis - Pertussis - Habitual cough - Tracheomalacia - CF
Features of cough in bronchitis
Wet cough
Features of cough in tracheomalacia
Life long loud cough
Goals of treatment for asthma
Minimal symptoms during day and night Minimal need for reliever medication No exacerbations (asthma attack) No limitation of physical activity Normal lung function (FEV1)
How to measure control in asthma
SANE
- short acting beta agonist / week
- absence school / nursery
- nocturnal symptoms / week
- exertional symptoms / week
Classes of medications used in asthma
Short acting beta agonists (SABA) Inhaled corticosteriods (ICS) Long acting beta agonists (LABA) Leukotriene receptor antagonists (LTRA) Theophyllines Oral steriods
S/Es of ICS
Height suppression (1cm) Oral candidiasis Adrenocortical suppression (very high doses)
Advantages of ICS
Decreased HTN
Decreased cataracts
What is a LABA always used with?
ICS
What is the LTRA drug?
Montelukast
Two types of delivery systems
MDI/Spacer
Dry powder device
Lung deposition with and without spacer
Without - < 5%
With - < 20%
What must be done to a spacer?
Washed monthly
Shaken between puffs to reduce static
What ages are suitable for dry powder devices?
Licenced in > 5s, < 8s cannot use them
Alternative management of asthma
Stop smoke exposure
Remove environmental triggers
- pets, house dust mites
Treatment of acute asthma attack in adults - the escalation of care
- Oxygen
- Salbutamol nebulisers
- Ipratropium bromide nebulisers
- Hydrocortisone IV or Oral prednisolone
- Magnesium sulphate IV
- Aminophylline / IV salbutamol
Drugs to avoid in asthma
Beta blockers
NSAIDs
Aspirin
Sedatives/strong opiates (unless in critical care)
What does a pMDI (meter dose inhaler) require?
Coordination
Benefits of using a pMDI with a spacer
Low oro pharyngeal deposition of aerosol
Reduced speed of aerosol
Decreases bad taste associated with aerosol deposition
Reduced risk of oral candidiasis and dysphonia with steriods
Reduced cold Freon effect in some
What does SABA stand for?
Short acting beta agonist
Examples of SABAs
Salbutamol
Terbutaline
S/Es of beta 2 stimulants
Tremor Cramp Headache Flushing Palpitations Angina
Are side effects of B2agonists common or rare in inhaled steroids or oral steroids?
Inhaled - rare
Oral - common
Examples of ICS (Preventers)
Beclomethasone
Budesonide
Fluticasone
Mometasone
Long term S/Es of oral steriods
Red cheeks Moon face Fat pads / buffalo hump Thin skin High BP Thin arms and legs Osteoporosis Poor wound healing Pendulous abdomen Red striation
S/Es of long term inhaled steriods
Dysphonia
Oropharyngeal candidiasis
What is dysphonia?
Hoarseness
Examples of ICS + LABA
Fostair (beclomethasone with formoterol)
Symbicort (budenoside with formoterol)
Flutiform (fluticasone propionate with formetrol)
Examples of LTRA
Monteleukast
Zafirlukast
Who are LTRAs most effective in?
Those who are highly allergic
How are LTRAs taken?
Oral
What is theophylline?
Non specific phosphodiesterase inhibitor and adenosine receptor antagonist - weak bronchodilator
S/Es of theophylline
Anorexia Headache Malaise Vomiting Nervousness Abdo discomfort Insomnia Tachycardia Tachyarrythmias Convulsions
Examples of LAMAs
Tiotropium bromide via spirivia respimat
What does LAMA stand for?
Long acting anti muscarinic
What is the main long term oral steroid used for asthma?
Prednisolone
What can abrupt cessation of long term oral steroids lead to and when would this occur?
Acute adrenal insufficiency
> 3 weeks
What happens in acute adrenal insufficiency?
Failure of adrenal glands to produced endogenous glucocorticoid
What is Omalizumab?
Monoclonal antibody (mab) against IgE
What is Omalizumab for?
IgE mediated severe allergic asthma
What is meplolizumab and what is it used for?
monoclonal antibody (mab) against interleukin 5 Poor asthma control (long term steroid or frequent steroid) with blood eosinophillia
What is sometimes tried as a last resort?
Immune suppressive drugs e.g. methotrexate, ciclosporin
Non pharmacological methods of controlling asthma
Patient education and self management plans Inhaler technique Smoking cessation Flu/pneumococcal vaccinations Treating comorbidities (Obesity, allergic rhinitis, GORD) Stepping down treatment when controlled Allergen avoidance Bronchial thermoplasty
What is the first line preventer in < 5s?
LTRA
What is the max dose of ICS used in children?
800 micrograms
Stepladder approach of treating asthma
- SABA as required
- Regular preventer
- very low dose ICS (or LTRA in < 5s) - Add on preventer
- add on LABA
- add on LTRA
- Increase ICS dose
When is a regular preventer needed?
Using inhaled B2 agonists 3x a week or more
Symptomatic 3x a week or more, or waking one night a week
Exacerbations of asthma in last 2 years
Management of acute asthma
- Mild
- SABA via spacer
- SABA via spacer and pred - Moderate
- SABA via nebuliser + pred
- SABA + ipra via neb + pred - Severe
- IV salbutamol
- IV aminophylline
- IV magnesium (neb)
- IV hydrocortisone
- nebulised bronchodilators
- intubate and ventilate
- antibiotics if pneumonia/bacterial infection
How much pred is given in acute asthma (mild/moderate) and for how long?
0.5 mg/kg/day for 7 days
What type of drug is ipratropium?
SAMA
How to assess patient with acute asthma?
Resp rate Work of breathing HR O2 sats Ability to complete sentences Confusion Air entry
Age and features of cough COPD vs asthma
COPD - > 35 years - persistent and productive
Asthma - any age - intermittent and non productive
SOB features asthma vs COPD
COPD - progressive and intermittent
Asthma - intermittent and variable
Nocturnal symptoms COPD vs asthma
COPD - uncommon unless in severe disease
Asthma - common
FH COPD vs asthma
COPD - uncommon unless family members also smoke
Asthma - common
What does a Ph < 7.35 represent in asthma? What does it require?
CO2 retention in a tiring patient and is an ominous sign in acute asthma
Intubation and ventilation may be needed
What does a normal PaCO2 in an acute asthma attack indicate?
Exhaustion and should be classified as life threatning
