Asthma Flashcards
What is asthma?
Chronic inflammatory disorder characterised by hyperactive airways leading to episodic bronchocontriction in response to stimuli.
How can asthma be classified?
Extrinsic= allergic/atopic- more in children
Intrinsic eg cold exercise, asprin use, b blockers- more in adults
What type of hypersensitivity is associated with asthma?
Type 1
What immune cell mediates asthma?
eosinophils
What are the consequences of the chronic inflammation in asthma?
Hypertrophy of airway smooth muscle increades mucus oedema epithelial nerve damage- sensory nerves exposed- hyperresponsiveness airway remodelling
What are the phases of an asthma attack?
Immediate bronchoconstriction
Late phase- inflammation
What is produced in allergic asthma?
Increased TH2
What does increased Th2 cause?
Increased IgE production
Eosinophilic infilatations
What causes the increase in IgE?
IL- 4
What causes the increase in eosinophils cells?
IL-5
What does the IgE do?
Binds to mast cells which degranulate upon reexposure to the antigen
What do mast cells release?
Chemotaxins and chemokines= platelet activating factor, prostoglandins
Smasmogens= histamine, leukotrienes
What are the symptoms of asthma?
Intermittent dyspnoea
Wheeze
Nocturnal cough
Sputum
What are the signs of asthma?
Hyperinflation
Hyperressonant percussion note
Diminished air entry
Polyphonic wheeze
What are the indications of a sever asthma attack?
Pulse >110
RR>25
PEF 33-50%
What are the indications of a life threathening asthma attach?
Silent chest cyanosis Unconcious Brady cardia PEF <33%
What investigations are used to diagnose asthma in an acute attack?
PEF
ABG shows hyperventilation as both PaO2 and PaCo2 decreased
How is chronic asthma investigated?
PEF
spirometry
skin prick
What are possible complications of asthma?
Pneumothorax
What are the treatments of asthma?
Step 1- SABA Step 2- Steroid Step 3 LABA Step 4- CystLT1 Cromolins Xanthines Monoclonals Step 5- prednisolone
