Asthma Pathophys

Question 1

Asthma

Answer 1

• Obstructive disease
• Resistance to the flow of air
  through the airways during
  inspiration and expiration
• FEV1 is <80% significant reduce compare to normal

Question 2

Factors effecting degree of resistance

Answer 2

• Airway diameter
  – Laminar or turbulent flow

Question 3

Symptoms of asthma

Answer 3

• Dyspnoea
• Wheezing shortness of breath
• Tight chest
• Cough
• Chronic unproductive cough
• Night-time wakening with breathlessness

Question 4

Asthma effect on airways

Answer 4

• Chronic inflammatory disorder of the airways
• Canbe reversible and induced by many stimuli
• Obstructive disorder

Question 5

3 main factors of asthma

Answer 5

• Airway constriction
• Airway hypersensitivity and responsiveness
• Mucous hyper-secretion

Question 6

Causes of asthma: genetic factors

Answer 6

• Cytokine response
  profiles

Question 7

Causes of asthma: Environment

Answer 7

• Allergens
• Pollutants
• Infection
• Stress
• Symptoms and chronic changes

Question 8

Age impact on asthma

Answer 8

• Altered the immune and adaptive immune response
• Causes symptoms and chronic changes

Question 9

Genetic impact on inflammation with asthma

Answer 9

• Intrinsic vulnerability interacting due to infection or allergy
• Inflammation depending on phenotype
• Bronchospasm
• Airway remodelling
• Airway obstruction

Question 10

Allergens effect asthma

Answer 10

House dust mite, pollen,
moulds, animals

Question 11

Chemicals effecting asthma

Answer 11

• Paints
• Hairspray

Question 12

Drugs effecting asthma

Answer 12

• Aspirin
• ß-blockers
• NSAIDs

Question 13

Food triggers of Asthma

Answer 13

• Colouring
• Nuts
• Preservatives

Question 14

Environmental trigger for asthma

Answer 14

• Smoking
• Wood dust

Question 15

Extrinsic asthma

Answer 15

• Caused by specific triggers
• Allergens specific trigger
• Smoking and occupational agent

Question 16

Intrinsic trigger

Answer 16

• Non-specific
• Cold dry air
• Exercise
• Virus

Question 17

Atopy

Answer 17

• Develop IgE antibodies to common antigens
• 1/3 +ve skin prick test - history of eczema and family history of asthma
• Early onset 98% - skin test
• Late onset 76% - skin test

Question 18

Hypersensitivity

Answer 18

• Allergen is presented on the dendric cells in lung
• Attach to Th0 helper lympocytes differentiate to Th2 lympocytes
• Activate B cells to make IgE
• Secreate cytokines stim mast cels and endothelial cells attracting eosinophils

Question 19

Hypersensitivity: Sensitisation

Answer 19

• Antigen present on dendric
• Activate helper T cells change to secrete Th2 cytokines
• Activates B-cells
• Plasma cells secrete antibodies

Question 20

IgE antibodies

Answer 20

• Binding to Fc receptor on mast cell (granulocytes and some mediators eg histamines)
• Fc region bind to mast cell in lung

Question 21

Mast degranulation

Answer 21

• Rexposure to allergen
• Allergen bind to IgE on mast cell
• Cross linking Ige RECEPTOR
• Cause mast cell degranulation
• Release histamine and inflammatory mediators (Vasodilation increase mucus)
• Attracts eosinophils
• Stimulate cytokines

Question 22

Asthma Biphasic (Early phase)

Answer 22

• Increased resistance to airflow
• Peak 30-60 mins after allergen exposure
• Subsidised 30-90 min later
• Drop in peak flow response to inflammatory mediators from mast cells

Question 23

Asthma biphasic (Late phase)

Answer 23

• Can occour long time after allergen exposure 6+ hrs
• Can cause night time asthma
• Continuation of inflammation
  characterised by an influx of eosinophils intothe lungs

Question 24

Leukotrine

Answer 24

• Immediate constriction of airways and mucus production
• Immediate response (sensitsation and challenge)

Question 25

Late asthmatic response

Answer 25

- Mucus hypersecreation - Damage to epithelial can cause airways remodelling - Caused by eosinophil

Question 26

Recurrent attacks hyperresponsive

Answer 26

- Days and weks after - Smooth muscle growth from build up of cytokines

Question 27

Bronchoconstriction

Answer 27

- Narrowing of airways smooth muscle contraction - Increased mucous decrease diameter - Air trapping hyperinflation

Question 28

Mucous plugging and hyperinflation

Answer 28

- Inspiration of air is allowed into alveolus - In exhalation the mucus plug can impede exhalation of air flow - Turbulent air flow around blockage cause characteristics wheezing

Question 29

Theraputic goals

Answer 29

- Minimum symptoms day and night - Minimal need for reliever inhaler - No excerbation - No limitation to activity and normal lung function

Question 30

Reliever inhaler

Answer 30

Open the airways of a patient suffering an asthma attack

Question 31

Preventer inhaler

Answer 31

Intervene in the remodelling process

Question 32

Vasodialation and increased permiability

Answer 32

- Inflammation causes swelling of tissue due to OEDEMA - Swelling and decrease in diameter