Asthma Flashcards
What is asthma?
chronic inflammatory condition of the airways causing episodic exacerbations of bronchoconstriction
bronchoconstriction
smooth muscles of airways contract
narrowing of airways
airway obstruction in asthma
reversible
responds to bronchodilators eg salbutamol
what is bronchoconstriction caused by?
hypersensitivity of the airways and can be triggered by environmental factors
typical triggers
infection night time or early morning exercise animals cold/damp dust strong emotions
presentation suggesting diagnosis of asthma
episodic symptoms diurnal variability - worse at night dry cough with wheeze and SOB history of other atopic conditions family history bilateral wheeze
atopic conditions
eczema, hayfever and food allergies
presentation indicating diagnosis other than asthma
wheeze related to coughs and colds - VIW
isolated/productive cough
no response to treatment
unilateral wheeze
first line investigations
fractional exhaled nitric oxide
spirometry with bronchodilator reversibility
further investigations
peak flow variability
direct bronchial challenge test
what do you use with direct bronchial challenge test?
histamine or metacholine
NICE guidelines asthma
Add SABA inhaler
add low dose ICS
add oral LTRA eg montelukast
Add LABA
Additional management of asthma
yearly flu jab
yearly asthma review
avoid smoking
Presentation of acute asthma
progressively worse SOB
fast resp rate
symmetrical expiratory wheeze on auscultation
reduced air entry
grading acute asthma - moderate
PEFR 50-75% predicted
grading acute asthma - severe
PEFR 33-50% predicted
resp rate >25
heart rate >110
unable to complete sentences
grading acute asthma - life threatening
PEFR <33%
sats <92%
tired, no wheeze - silent chest
haemodynamic instability
treating moderate acute asthma
nebulised beta 2 agonst - salbutamol 5mg
nebulised ipratropium bromide
steroids - oral prednisolone or IV hydrocortisone
treating severe acute asthma
oxygen: maintain sats 94-98%
aminophylline infusion
consider IV salbutamol
life threatening acute asthma
IV magensium sulphate infusion
intubation if severe
ABGs in asthma
initially respiratory alkalosis as tachypnoea leads to CO2 drop
respiratory acidosis due to high CO2 is very bad sign
monitoring acute asthma
resp rate, resp effort
peak flow, O2 sats, chest auscultation
salbutamol and potassium
monitor serum potassium on salbutamol as can cause potassium to be absorbed from blood into cells and cause a fast heart rate
