Asthma Flashcards
what is asthma?
type of obstructive lung disease characterised by paoxysmal and reversible airway bronchoconstriction, as a result of inflammation of the respiratory airways and bronchial hyperresponsiveness
what is the atopic triad?
- asthma
- allergic rhinitis
- atopic eczema
what type of hypersensitivity reaction is asthma?
type 1 hypersensitivity reaction
what does airway inflammation lead to?
airway remodelling
what is airway remodelling characterised by?
- bronchial smooth muscle hypertrophy
- bronchoconstriction
- mucous gland hypertrophy
- vasodilation and increased vascular permeability
what symptoms are associated with asthma?
- wheeze
- dyspnoea
- cough - may be nocturnal
- chest tightness
- diurnal variation = worse in mornin
- worse following exercise or NSAIDs/beta-blockers
what is a sign on examination of severe disease?
silent chest
what are the signs of a severe attack?
- inability to speak in complete sentences
- respiratory rate >25
- peak flow 33-50% predicted
what are the signs of a life-threatening attack?
- silent chest
- confusion
- bradycardia
- cyanosis
- exhaustion
what are the examination findings in asthma?
- tachypnoea
- hyperinflated chest
- hyper-resonance on chest percussion
- decreased air entry
- wheeze
what investigations are carried out in chronic asthma?
- peak flow
- fractional exhaled nitric oxide (FeNO)
- spirometry
what is the predicted value for peak flow in asthma?
variability >20% predicted
what is the predicted results from a fractional exhaled nitric oxide (FeNO) in asthma?
- > 40 ppb in adults
- > 35 ppb in children
what are the expected spirometry results in asthma?
- low FEV1
- preserved FVC
- FEV1/FVC <0.7
obstructive spirometry which can be reversed on administration of a bronchodilation
what investigations should be performed in acute asthma?
- ABG
- routine blood tests - to check for precipitating causes
- chest x-ray - to check for precipitating causes
what can ABG results demonstrate in an acute asthma attack?
type 2 respiratory failure (low PaO2 and high PaCO2)
sign of life-threatening attack
what is the management for an acute asthma attack?
- ensure a patent airway
- oxygen saturations of 94-98%
- nebulisers = salbutamol, ipratropium
- steroids = oral prednisolone or IV hydrocortisone (if severe)
- IV magnesium
- IV aminophylline
- intensive care
what non-pharmalogical management can be undertaken in chronic asthma?
- smoking cessation
- avoidance of precipitating factors
- review inhaler technique
what is step 1 of asthma management?
short-acting inhaled B2-agonist
salbutamol
what is step 2 of asthma management?
low-dose inhaled corticosteroid
if symptoms are presisting at night or >3 times a week
what is step 3 of asthma management?
long-acting B2-agonist
no benefit = stop and increase ICS
inadequate benefit = continue and increase ICS
what is step 4 of asthma management?
leukotriene receptor antagonist + high-dose steroid + oral B2-agonist
what are the asthma mimics?
- acid reflux
- churg-strauss syndrome
- allergic bronchopulmonary aspergillosis (ABPA)
what is acid reflux?
acidic contents of the stomach are regurgitated into the oesophagus
