What is the definition of asthma
what type of disease is asthma
Heterogenous disease usually characterised by chronic airway inflammation
what are the 4 symptoms of asthma
How many people does asthma affect
◦5.4 million people in the UK receive treatment for asthma: 1 in 11 children and 1 in 12 adults
◦Affecting 1 – 18% of the population of different countries
what is a phenotype
A phenotype is defined as the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
Name the 5 differnet phenotypes of asthma
◦Allergic asthma ◦Non-allergic asthma ◦Adult-onset (late-onset) asthma ◦Asthma with persistent airflow limitation ◦Asthma with obesity
Describe allergic asthma
- has lots of eosinophils
describe non allergic asthma
Describe adult-onset asthma
describe asthma with persistent airflow limitation
what receptors cause bronchodilation
what receptors cause bronchoconstriction
What holds the large airways open
How do you work out flow
pressure change/resistance
what causes an increase in flow
- or decreased resistance (pouseille’s law: resistance 1/r4)
Describe the pathology of asthma
Inflammatory process:
Describe what happens in the acute and late phase pathology of asthma
Acute phase: Mast cells cause - bronchospasm - oedema - mucous
Late phase
TH2 helper cells cause B cells to be produced and this causes IgE and eosinophil production this leads to:
- constriction
- muco-secretion
What are the extrinsic, intrinsic and occupational causes of asthma
Extrinsic
Intrinsic
Occupational
- allergens at work
how can you diagnose asthma
- clinical assessment supported by objective evidence of variable airflow obstruction or airway inflammation
What are the features that make asthma more likely
More than one episode of
Variability
- worse at night and in the O-ring (diurnal variability)
why do you produce NO in asthma
- eosinophils use inducible nitric oxide synthetase (iNOS) to produce NO
What are the differential diagnosis of asthma
What are the differences between Asthma and COPD
Asthma
COPD
what is the treatment difference between asthma and COPD
Asthma is chronic inflammation so you use a higher dose of steroids whereas COPD you use lower doses of steroids