Adult Asthma Flashcards
What is important in defining asthma?
- Asthma is more of a concept than a definition
- Characterised by increased irritability (responsiveness), widespread narrowing of airways that changes in severity
Why do airways narrow when they become inflamed?
They narrow as they become thicker and mucous and debris falls into the airway
What is airway inflammation mediated by?
The immune system
What is the difference in diagnoses by sex?
Women are affected more than men
Give some examples of how asthma impacts peoples lives?
Some asthmatics are totally and very limited by asthma. They struggle with:
- Running
- Stairs
- DIY
- Gardening
- Sleeping
What is the impact of asthma on the NHS?
It is mainly dealt with in primary care but there are 67,000 admissions to hospital.
What is the change in prevalence linked to?
Changes in environment
What are the proven risk factors linked to asthma?
- Genetic- atopy
- Occupation
- Smoking
What are the 2 genetic associations with asthma that linkage studies have identified?
- Immune response genes: IL-4, IL-5, IgE
- Airway genes: ADAM33
How does genetics play a role in asthma?
- Inherited tendency to IgE response to allergens.
- Often accompanied by eczema, hay fever or food allergy
What form of atopy is most influential?
Maternal
What is the most common cause of occupational asthma?
Bakers who are exposed to flour and microbes
What are some examples of occupational asthma allergens?
- Isocyanates: twin pack paints
- Colophony: welding solder flux
- Laboratory animals: rodent urinary products
- Grains: wheat proteins, grain mites
- Enzymes: subtilisin, amylase
- Drugs: antibiotics, salbutamol
- Crustaceans: prawns, crabs
What does maternal smoking during pregnancy cause?
- Decreased FEV1
- Increased wheezy illness
- Increased airway responsiveness
- Increased asthma and severity
What is the grandmother effect?
If your grandmother smoked during pregnancy then you are 2.6X more likely to have asthma
What is the grandmother effect due to?
Mouse work suggests epigenetic modification of oocytes
What speculative risk factors are there?
-Obesity
-Diet
-Reduced exposure to microbes/microbial products
-Indoor pollution
-House dust mite
-Cat
Grass pollen
Speculative: What is an obese body mass index positively associated with?
- Asthma
- Wheezing
- Airway hyperreactivity
Speculative: Supplements in asthma?
There are some associations between supplements and asthma but they have not effect in established disease
Speculative: Exposure ot what microbial products is believed to reduce the likelihood of developing asthma?
- Endotoxin
- Glucans
- Extracapsular polysaccharide
Speculative: Exposure to what chemical products is thought to increase the likelihood of asthma?
- Volatile organic compounds
- Formaldehyde
- Fragrances