Asthma Flashcards
(27 cards)
what is asthma characterised by
dyspnoea, cough and wheeze caused by REVERSIBLE airway obstruction
what factors contribute to airway narrowing
bronchial muscle contraction, mucosal swelling/inflammation, increased mucus production
symptoms of asthma
intermittent dyspnoea, wheeze, cough (often nocturnal), sputum
precipitants of symptoms in asthma
cold air, exercise, emotion, allergens, infection, smoking, NSAIDS, B blockers
what is the variation in asthma
diurnal variation in symptoms and peak flow. morning dipping of peak flow
questions to ask when assessing asthma
exercise tolerance, sleep disturbance, acid reflux- 40-60% of those with asthma have reflux; other atopic disease; home- pets, feather pillows etc.
signs asthma
tachypnoea, audible wheeze, hyperinflated chest, hyperresonant percussion, decr air entry,
signs in severe attack
can’t complete sentences, pulse >110bpm, resp rate >25/min, PEF 33-50%
signs in life threatening attack
silent chest, confusion, exhaustion, cyanosis, bradycardia, PEF <33%
when does PaCO2 rise
near fatal attack. signifies failing respiratory effort
tests in acute asthma
PEF, sputum culture, FBC, U and E, CRP, blood culture. ABG- normal or slightly low PaO2 but decr PaCO2 (hyperventilation)
tests in chronic asthma
PEF monitor, spirometry. CXR- hyperinflation; skin prick tests could help identify allergen. histamine or methacholine challenge. aspergillus serology
differential diagnosis asthma
pulmonary edema, COPD, large airway obstruction, SVC obstruction, pneumothorax, PE, bronchiectasis, obliterative bronchiolitis
associated diseases with asthma
acid reflux, polyarteritis nodosa, Churg Strauss syndrome
what are the steps in the management of chronic asthma
1- occasional SABA. 2- inhaled steroid (beclametasone). 3- LABA (salmeterol). 4- modified release B agonist. 5- regular oral prednisolone, high dose inhaled steroids
how do B agonists work
relax bronchial smooth muscle acts within minutes. salbutamol- inhalation (also PO, IV).
side effects B agonists
tachyarrhythmias, decr K, tremor, anxiety.
example of long acting B agonist and when can these be useful. side effects
salmeterol, formoterol. nocturnal symptoms, reduce morning dips. SE- same as salbutamol, paradoxical bronchospasm
what is the function of corticosteroids
act over days to decrease bronchial mucosal inflammation. inhaled to reduce systemic effects
how are oral steroids given
acutely- high dose short course eg prednisolone, and longer term lower dose.
MOA aminophylline
inhibits phosphodiesterase so decreasing bronchioconstriction by increasing cAMP levels.
what is the problem with aminophylline, and side effects
narrow therapeutic index. arrhythmias, GI upset, fits
anticholinergics used in asthma, MOA
decr muscle spasm synergistically with B agonists. ipratropium, tiotropium
other drugs used in the management of asthma
cromoglicate, leukotriene receptor antagonists (montelukast), anti-IgE monoclonal antibody (omalizumab)
