Asthma (Etiology, Epidemiology, Pathology and Risk Factors) Flashcards Preview

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Flashcards in Asthma (Etiology, Epidemiology, Pathology and Risk Factors) Deck (47):
1

What is asthma?

Asthma, whatever the severity, is a chronic inflammatory disorder of the airways mediated by mast cells, eosinophils and T-lymphocytes
- inflammation underpins the whole entity

2

What does airway inflammation contribute to?

- airway hyper-responsiveness (bronchoconstriction)
- airflow limitation
- respiratory symptoms (cough, wheezing etc.)
- disease chronicity (if inflammation not addressed)

3

What does the inflammation cause?

Recurrent wheezing, breathlessness, chest tightness and cough, particularly at night, and is associated with widespread but variable obstruction that is at least partly reversible.
- the inflammation causes airway hyper-responsiveness
- fixed airway obstruction may occur (NB! due to scar formation occurring in the airways)

4

What are the 3 key words in asthma?

1. Inflammation
2. Airway hyper-responsiveness
3. Airway remodeling

5

What is another term for airway hyper-responsiveness?

Airway hyper-reactivity

6

What is airway remodeling?

Describes what happens as a consequence of chronic asthma
- hypertrophy and hyperplasia of smooth muscle and subepithelial fibers

7

What is asthma often described as?

A chronic eosinophilic bronchitis

8

Pathology of asthma:

Changes include muscosal oedema, mucus hypersecretion, smooth muscle hypertrophy, loss of airway epithelium and infiltration of inflammatory cells

9

Asthma aetiology

Asthma occurs in a given individual as a result of a combination of genetic predisposition and exposure to appropriate environmental stimuli

10

What are "inducers"?

e.g. allergens or occupational agents
- cause airway inflammation, bronchial hyper-reactivity and symptoms of asthma
= disease is brought on

11

What are "trigger factors"?

e.g. exercise or irritants result in exacerbations of asthma
= disease is already there, something makes it worse

12

Which antibodies are involved in asthma?

IgE

13

Who is likely to get asthma?

A number of factors determine the likelihood of developing asthma
- following exposure to an irritant in the air a normal immune and defense response occurs; in people with asthma the response may become exaggerated
- airway inflammation and hyper-reactivity
i.e. airways would over-react to things that would just be minor irritants in people without asthma

14

What are the two types of asthma conventionally described?

1. Extrinsic (atopic)
2. Intrinsic (non-atopic)

15

What is extrinsic (atopic) asthma?

- hereditary predisposition to generate IgE in response to commonly encountered allergens in environment
- asthma usually begins in childhood
- may be history of eczema

16

What is intrinsic (non-atopic) asthma?

- causal agent not identified
- less frequent childhood
- rarely family history
- no hayfever, eczema or other allergic manifestations

17

What is a risk factor for asthma?

Risk factor relates to an entity that increases the likelihood of getting a disease or a condition

18

Significance of risk factors in asthma:

- asthma may develop with or without various risk factors
- greater number of risk factors > potential likelihood for developing asthma

19

Why is family history relevant in asthma?

genetic predisposition has been demonstrated

20

Which genes have been linked to asthma?

Recently 2 asthma genes have been identified:
1. ADAM 33
2. PH 11

21

Which chromosomes are linked to asthma?

5, 11, 12

22

Which infections are risk factors for asthma?

Upper respiratory tract infections:
- mainly viral
- RSV (respiratory syncytial virus)

23

What are some allergens that are risk factors for asthma?

Pollen, house dust mites, cockroaches, pets

24

What are some air pollutants that are risk factors for asthma?

particulates (PM10), ozone, nitrogen oxides, SO2

25

When is exercise a more common risk factor for asthma?

In children
- particularly in cold air

26

Which gender is at more risk of asthma?

Initially males > females
Later females > males

27

Which food and drinks may be risk factors for asthma?

Dairy products, alcohol, peanuts, various fruit juices

28

Which additives are risk factors for asthma?

Metabisulphate, tartrazine, monosodium glutamate

29

What are some work related risk factors for asthma?

Irritants and specific sensitizers

30

What are hormonal risk factors of asthma?

Premenstrual exacerbations, pregnancy

31

Regarding birth, what are some risk factors of asthma?

Low birth weight / pre-term delivery:
- birthweight <2.5kg or <37 weeks gestation
- small (or excessively "floppy") airways

32

Which medical conditions are risk factors for asthma?

- rhinitis / sinusitis ("united airway")
- obesity
- gastroesophageal reflux

33

Which drugs may be risk factors for asthma?

aspirin, NSAIDs, beta-blockers (including eye droppers), & as part of an anaphylactic response to other drugs

34

What are 2 other important risk factors for asthma?

- emotional stress
- smoking

35

What is occupational asthma?

Asthma caused by specific sensitizing agents inhaled in the workplace
= increasingly important

36

What is important in the consultation of a patient with suspected occupational asthma?

A detailed history:
- work-related symptoms
- typically improves at weekends & on holiday
- compensation

37

Occupational asthma: which occupation is associated with the following precipitant?
Isocyanates

Paint sprayers

38

Occupational asthma: which occupation is associated with the following precipitant?
Animal proteins (e.g. excreta)

Laboratory workers

39

Occupational asthma: which occupation is associated with the following precipitant?
Reactive dyes

Manufacturing

40

Occupational asthma: which occupation is associated with the following precipitant?
Fungi

Brewers

41

Occupational asthma: which occupation is associated with the following precipitant?
Platinum salts

Platinum miners

42

Occupational asthma: which occupation is associated with the following precipitant?
Acid anhydrides

Manufacturing

43

Occupational asthma: which occupation is associated with the following precipitant?
Drugs and enzymes

Pharmaceutical workers

44

Occupational asthma: which occupation is associated with the following precipitant?
Plicatic wood (Western Red Cedar)

Forestry workers

45

Occupational asthma: which occupation is associated with the following precipitant?
Pinewood resin (colophony)

Joiners

46

Occupational asthma: which occupation is associated with the following precipitant?
Shellfish proteins

Seafood workers

47

What can be done to prevent asthma?

- avoid provoking factors where possible in predisposed individuals
- education of caregivers and patients