Asthma Flashcards
Describe the pathophysiology of asthma
Genetic predisposition, Atopy (tendency to develop allergenic diseases), Environemental triggers (URTI), allergens, smoking, cold air, exercise, emotion, chemicals)
Lead to:
Bronchial inflammation:
Oedema,
Mucus production
Infiltration with cells (eosinophils, mast cells, neutrophils, lymphocytes)
Bronchial hyperresponsiveness - twitchiness to inhaled stimuli
Airway narrowing:
Reversible airway obstruction e.g. peak flow variability
Symptoms: Wheze Cough Breathlessness Chest tightness
What are the clinical features of asthma?
Polyphonic (multiple pitch) wheezing - whistling in chest on breathing out
Hx/FHx of atopy
Diurnal variation
In chronic asthma, hyperinflation, generalised polyphonic expiratory wheeze with prolonged expiratory phase.
Harrison’s sulci - depressions at base of thorax associated with muscular insertion of diaphragm.
What features make asthma more likely?
Symptoms worse at night and early morning
Nonviral triggers
Interval symptoms i.e. symptoms between acute exacerbations
Personal or FHx or atopy - eczema, allergic rhinitis
Positive response to bronchodilator therapy
Questions to ask in asthma?
ODCSTPRAP
Onset Duration Course Severity Timing Preceiptants, Relieving factors, Additional symptoms, Previous episodes
Frequency Triggers, sports Sleep disturbance Interval symptoms between exacerbations School missed?
What features make asthma less likely?
Wet cough Sputum production Finger clubbing Poor growth Suggest chronic infection such as cystic fibrosis or bronchiectasis
What investigations in asthma? Spirometry result?
In younger children Hx/Ex alone
Skin prick testing fro common allergens may be preformed to aid the diagnosis of atopy and identify allergens.
If there is uncertainty, PEFT may be measured or spirometry performed.
(most children > 5 can do these)
Poorly controlled asthma leads to increased variability in peak flow, with both diurnal variability (Worse in morning) and day to day vraibitliy.
Spirometry shows at obstructive picture: FEV1 < 80% FEV1:FVC <70% With reversibility: 12% improvement in FEV1 after inhaling bronchodilator
Describe the management progression of asthma.
Reliever therapy - salbutamol
+ Low dose ICS: budesonide, fluticasone, beclometasone
+ add-on preventer
Describe the management progression of asthma.
Reliever therapy - salbutamol \+ Very Low dose ICS: budesonide, fluticasone, beclometasone \+ 5 or older LABA, <5 LTRA Increase ICS dose to low dose Consider trial of LTRA Consider ICS up to medium dose \+ Theophylline Daily steroid tablet
Describe bronchodilator therapy.
Inhaled beta 2 agonists SABA: Salbutamol, Terbutaline relievers 2-4 hours, rapid onset
LABA
Salmeterol, Formoterol
12 hours
SAMA
Ipratropium bromide
How do steroids work in asthma?
Decrease airway inflammation, decreasing symptoms, asthma exacerbations and bronchial hyperactivity.
Preventers - prophylactic and so must be taken regularly.
What are side effects of inhaled corticosteroids?
Mild reduction in height velocity, but this is usually followed by catch up growth
In high doses:
Impaired growth
Adrenal suppression
Altered bone metabolism
So use very los doses
What is the first choice of add-on therapy in children over 5? Under 5?
What if symptoms are not controlled?
Over 5 - LABA -salmeterol or formoterol
Under 5 - LTRA such as monteleukast (tablet)
slow release oral theophylline, however has a high incidence of side-effects (vomiting, insomnia, headaches, poor concentration)
How can you prevent the adverse effect on growth of inhaled corticosteroids? When is this used?
Use oral prednisone on alternate days - required only in severe persistent asthma where other treatment has failed
What is the treatment of severe atopic asthma?
Anti-IgE therapy (omalizumab), injectable monoclonal antibody that acts against IgE that mediates allergy
What is complete control of asthma?
Absence of daytime or night-time symptoms, no limit on activities including exercise, no need for reliever use, normal long function, no exacerbations in previous 6 months
