Asthma Flashcards
What is the definition of asthma
A disease characterised by an increased responsiveness of the trachea and bronchi to various stimuli and manifested by a widespread narrowing of airways & bronchial inflammation, that changes in severity either spontaneously or as a result of therapy; resulting in episodic wheeze and/or cough
What is the two stand out features of asthma
variable and reversible
How is asthma characterised
Wheeze
What are some examples of the multiple triggers
Exercise
Allergen
Cold weather
smoke
perfume
Upper Respiratory Tract (URT) infections,
pets, trees, grass pollen, food, aspirin.
What is the Pathophysiology of asthma
airway inflammation mediated by immune system
What are the proven risk factors of asthma
and other possible risk factors
Genetics
Occupation
Smoking
Possible:
Obesity Diet Reduced microbe exposure (farm children less likely due to previous exposures) Chemical products Environmental exposures Abnormal lungs
What genetic tendency can be inherited that could trigger asthma?
An atopic tendency - which increase IgEs response to allergens
Is it maternal or paternal atopy genetics that is most significant in an IgE to respond to an allergen
What are the two groups of genes that increase atopic tendencies development of asthma
Maternal - epigenetic modification of oocytes
Immune response geneses (IL-4, IL-5, IgE)
Airway response genes (ADAM33)
What is the affects of maternal smoking during pregnancy
Decreases FEV1
Increases airways responsiveness
(therefore increase the risk of asthma/wheezy illness development)
Increases severity
Does environmental exposure directly cause asthma?
No, because the atopy genetics need to be previously present for environmental factors to increase the sensation and trigger asthma
What is the symptoms of asthma
wheezing attacks episodic shortness of breath (dyspnoea) chest tightness cough – paroxysmal(outburst)/ dry sputum (occasional)
What are other examples of airflow obstruction diseases
COPD (irreversible AFO)
bronchiectasis
bronchiolitis
Cystic Fibrosis
What are examples of localised airflow obstructions
inspiratory stridor (obstruction of windpipe)
tumour
foreign body
What are the main areas of concern when diagnosing asthma during a history taking
Past medical history
Current drugs
Family medical history
social medical history
What signs on examination prove its probably not asthma
Clubbing
cervical lymphadenopathy
Stridor (harsh or grating sound)- upper airway obstruction
Asymmetrical expansion
Dull percussion note (lobar collapse or effusion)
Crepitations- crackling/rattling sound (bronchiectasis, CF, alveolitis, LVF)
What are the essential investigations carried out for asthma looking for
Airflow obstruction
Variability and/or reversibility of airflow obstruction
In a spirometry:
What does the FVC investigate
What is the FEV1/FVC ratio that shows the airway obstruction
Lung volume
<70%
If the FEV1/FVC is <70% what is the predicted FEV1
<80%
What is the factor that can differentiate between COPD and asthma
Reversibility
in spirometry is the results show an airway obstruction what are the further testing that occurs to differentiate it from COPD
Full pulmonary function test
Test with B2 agonist
Test with steroids
What is the full pulmonary function tests carried out to exclude COPD and emphysema
Breathing in helium to show that there is an increase in the residual volume and TLC as there is a problem in expiring
Breathing in CO to prove that there is no problem in gas exchange therefore the alveoli are still efficient
NO - people with asthma will have a higher level of NO in there breath
What does the test of the B2 agonist Salbutamol and steroid test prove
If the bronchodilaiton is reversible
and the reversibility with steroids differentiates asthma from COPD
When would no reversibility be shown when using salbutamol inhaler
When there is no bronchocontriction or the bronchocontriction is to severe
What is the problem with spirometry
Therefore what needs to be investigated if the results are normal
Lacks specificity
the variability of the potential asthma
- as this can be a problem in diagnosing
What tests are carried out to asses the variability
Peak flow monitoring, twice daily for two weeks
What is investigations for asthma
oChest X Ray- hyperinflated / hyperlucent lungs - (no effusion, collapse, opacities, interstitial changes)
oSkin prick testing or total and specific IgE (both atopic status)- put allergens under skin and check for wheal and flare reaction
oFull blood count – eosinophilia (atopy)
oArterial blood gases (PaCO2/PaO2)
- if in doubt
o Full Pulmonary function test (He/CO/NO)
o Spirometry
o Test reversibility (B2 agonists/Steroids)
What tests need to be taken to asses the severity of acute asthma
o Ability to speak- whether patient can talk to you
o Heart rate-pulse
o Respiratory rate
o PEF- peak expiratory flow
o Oxygen saturation / Arterial blood gases
Above what heart rate and reparation rate shows a severity in asthma
> 110
>25
What is the signs asthma has become life threatening and near fatal
hyperventilating and brachycardic
Raised PaCO2 levels
How long till you re-measure the spiriometry in a brobchodilation salbutamol test and after steroid treatment
15 minutes
2 weeks
What is needed for conformation of asthma
Serial peak flow readings 2 hourly best: 5/d minimum 2 pairs of exposed/unexposed periods (at least) Antibodies Bronchial constriction
What do paediatric asthma and adult asthma have in common?
What is the differnences
- Symptoms
- Common occurrence
- Same triggers
- Same treatment
- Same pathology
Severe asthma = childhood
Occupational asthma = adult hood
What triggers the onset of asthma
- Genes
- Inherently abnormal lungs
- Early onset atopy – syndrome characterised by tendency to be hyper allergenic
- Later exposures
- rhinovirus
- exercise
- smoking
What is the carrying differences and inconsistencies of asthma in varying patients
“Transient” vs persistent - short term/long term Different severities Different age at onset Heterogeneity in response Different triggers
What is the differences in children’s airway and what outcome does this have on the sound of the wheeze
Children’s airways are smaller
and more likely to be musical
What are respiratory conditions that are mistaken as a wheeze
rattle - fluids such as saliva and bronchial secretions accumulating in the throat and upper chest
stertor- partial obstruction of airway above the level of the larynx = heavy snoring or gasping
stridor -
Obstructed windpipe or larynx
resulting in loud, harsh, high pitched respiratory sound
What treatment is used to measure if the predictted asthma will respond
inhaled cortico steroids for 2 months
What is the treatment for infrequent episodes of a wheeze
Salbutamol
Over what age is the symptoms presented most likely to be asthma
What is the likely diagnosis for baby under 18 months
age 5
Infection
What are the four different types of coughs that can be misdiagnosed as asthma
Bronchitis
- loose rattly cough
- noisy breathing
Pertussis (whooping cough)
- coughing fits
- vomiting colour change
Habitual cough
Tracheomalacia
- Life long cough
If a wheeze is not present, the cough is moist and it responds to antibiotics, what is the diagnosis?
Bacterial bronchitis
