Clinical features of asthma in adults Flashcards
Closest definition of asthma?
increase responsiveness of airways
airway obstruction
symptom variability
symptoms of asthma?
wheezing
coughing
shortness of breath
chest tightness
Prevalence of asthma?
higher in childhood- mostly males
adulthood- mostly females
Pathophysiology of asthma?
widespread narrowing of airways
increased airway reactivity - causes airway narrowing - which ca be spontaneous or in response to stimuli
How has a hereditary feature to asthma been proved?
-disease clustering in families
-twin, family and population based studies
What is atopy?
body’s predisposition to develop an antibody called Immunoglobulin E in response to exposure to environmental allergens and is an inheritable trait
associated with allergic rhinitis, asthma , hay fever and eczema
When does the risk of asthma increase?
first degree family member has asthma or another atopic disease
maternal atopy most influential
maternal smoking during pregnancy
-reduction in FEV1
-increased wheeze
-increase airway responsiveness
-increased asthma in children born to these mothers
Epigenetic phenomena
- “grandmother effect”
-tobacco smoke switches on genes which increase asthma risk in subsequent generations
occupation
bakers, painters and shellfish workers
obesity
diet
“hygiene hypothesis”
-microbial diversity appears to be important in reducing the risk of asthma
What do patients often present with?
wheeze
cough
breathlessness
chest tightness
sputum (occasionally)
evidence of variation
triggers (different for each individual and also cause variable symptoms)
What are other important aspects in the history for diagnosing asthma?
PMHx
-history of asthma in childhood , bronchitis or wheeze in infancy?
-eczema
-hayfever
Drugs
-current inhalers (check technique), other asthma therapies, compliance
-beta blockers, aspirin , NSAIDS
-effects of previous drugs/ inhalers
family
asthma and other atopic disease
social
-tobacco
recreational drug use
vaping
pets
occupation (past and present)
psychological aspects
What might be seen in clinic with someone who potentially has asthma?
- somebody breathless on exertion
-hyperinflated chest
-wheeze
When is it probably not asthma in the clinic?
-finger clubbing, cervical lymphadenopathy (point to lung cancer)
-stridor (harsh wheeze on inspiration)- points towards foreign body obstruction or tumor obstruction
-assymetrical expansion , dull percussion note (collapse/ pleural effusion and pneumonia)
-crepitations (crackles on listening to lungs) (bronchiectasis, Cystic fibrosis , Interstitial lung disease ,Left Ventricular Failure)
What is the method to differentiate other causes of wheeze, cough and dyspnoea?
generalised airflow obstruction:
-CODPD (irreversible)
-bronchietasis
-cystic fibrosis
localised airway obstruction (inspiratory stridor=large airways)
tumour
foreign body
cardiac causes
heart failure
valvular heart disease
What are we looking for in patients with an intermediate probablity and history of asthma?
airflow obstruction
variability and / or reversibility of airflow obstruction
What is FEV1and FVC?
forced expiratory volume in one second
FVC- total amount of air we can exhale
What do FEV1/FVC ratios mean?
<70%- airflow obstruction
Will asthmatics have normal spirometry?
they can have obstruction or have normal spirometry
What are next steps when spirometry comes back as obstructed?
full pulmonary function and or reversibility testing (beta 2 agonist or oral steroid)
What happens in a full pulmonary function test?
perform gas transfer test
- measures gas transfer of carbon dioxide to haemoglobin
-in asthma: gas transfer preserved or even increased
COPD: reduced due to alveolar reduction and structure of lungs due to smoking
What is reversibility?
Check the FEV1 15 mins before and 15 mins after an either inhaled or nebulized dose of salbutamol and check for improvement
Test to distinguish between asthma and COPD?
response to oral corticosteroids
keep peak flow chart
2 week spirometry
What are the steps after a patient has suspected asthma but normal spirometry?
- check for variability of airflow obstruction
peak flow meter and chart twice a day
suggestive of asthma :
morning/ nocturnal dips decline over weeks/ days variability >20% on >3 days a week
What is the specialist test for suspected asthmatics with normal spirometry?
given methacholine
histamine
mannitol
What are other useful investigations for asthma?
chest x- ray - hyperinflated , hyperlucent
skin prick testing
total and specific IgE- atopic individuals
full blood count - high level of eosinophilia more likely to have atopy - and asthma
