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Flashcards in Asthma Deck (24)
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0
Q

What changes to the airway wall is seen in asthma?

A

Thickening of smooth muscle and basement membrane

Damaged epithelium

1
Q

What is asthma?

A

A chronic condition characterised by

  • airway wall inflammation
  • airway wall remodelling
  • reversible airflow obstruction
  • increase in airway responsiveness to various stimuli
2
Q

What happens to airflow when triggers cause airway smooth muscle to contract and why?

A

Reduced airway radius
Increased resistance
Reduced airflow

3
Q

Risk factors for asthma?

A
Genetic risk
Hygiene hypothesis
Sensitisation to airborne allergens such as
-pollution
-house dust mites
-pollen
-tobacco smoke
4
Q

Triggers of airway smooth muscle contraction?

A

Histamine
Muscarinic agonists
Cold air
Arachidonic acid metabolites such as prostaglandins and leukotrienes

5
Q

Symptoms of asthma?

A

Wheeze
Dry cough - worse at night and can cause lack of sleep, poor performance at school
Breathlessness with exercise
Chest tightness

6
Q

What is a wheeze?

A

A high pitched, EXPIRATORY sound
Originates in airways narrowed by compression or obstruction
Can be of variable intensity and tone

7
Q

Examinations for asthma?

A

Inspection - look for hyperexpansion (Barrel chest), general health - eczema, hay-fever, lethargy, can they speak?

Percussion- will be hyper-resonant

Auscultation - polyphonic wheeze

8
Q

How does spirometry help in diagnosis asthma?

A

Produce a flow volume loop
Have a low peak expiratory flow rate (can’t breathe out quickly)
Low FEV1/FVC a ratio

9
Q

What happens to the FEV1/FVC ratio after administration of salbutamol?

A

See a greater than 12% increase

10
Q

What allergy testing can be done in aiding diagnosis of asthma?

A

Skin-prick to aero-allergens of eg
Cat, dog, house dust mites,

Look at blood IgE level,s for specific aero-allergens

11
Q

Why are chest X-Rays used in the diagnosis of asthma?

A

Can exclude other diseases, inhalation of foreign body, pneumothorax

12
Q

In the pathophysiology of asthma, what does exposure to the antigen cause?

A

CD4 T cells differentiate into T helper cells

Secrete IL-4 and IL-5

13
Q

What do IL-4 and IL-5 do?

A

IL-4: causes B cells to differentiate into plasma cells and secrete IgE

IL-5: makes eosinophils and mast cells reactive to new antigen

14
Q

What does IgE do?

A

Binds to mast cells in the mucosa
Waits to come into contact with the antigen again
On re-exposure, mast cells are activated and de-granulate to release inflammatory mediators

15
Q

What inflammatory mediators are released by mast cells?

A

Histamine
Prostaglandins
Leukotrienes

16
Q

What does histamine do in an asthma attack?

A

Smooth muscle contraction

Increased vascular permeability

17
Q

Why do asthmatics have an increased response to antigens?

A

Increased number of mast cells in their airway secretions and epithelial linings of lungs

18
Q

What is the late phase reaction?

A

Due to collection of eosinophils and neutrophils

More sustained inflammation, less bronchoconstriction

19
Q

How does remodelling of the airways occur?

A

Epithelium is stressed and damaged with the loss of ciliated columnar cells
Deposition of collagen causes basement membrane to thicken
Smooth muscle undergoes hyperplasia - thickening

20
Q

Precipitating factors for asthma attacks?

A
Can occur spontaneously
Lack of treatment adherence
Respiratory virus infections associated with common cold
Exposure to allergen
Exposure to a triggering drug eg NSAID
21
Q

How can education be used in the treatment of asthma?

A

So patients can recognise symptoms
Use medication timely
Use services appropriately
Develop a personal asthma action plan

22
Q

How can asthma be prevented?

A

Stop smoking
Fresh air
Reduce exposure to allergens and triggers
Weight loss

23
Q

Pharmacological management of asthma?

A

β2 adrenoagonists
Muscarinic antagonists to provide short term relief eg salbutamol
Anti-inflammatory agents eg corticosteroids
Preventer therapies