asthma

Question 1

possible triggers for asthma

Answer 1

1. Inflammation:
   Allergy
   Viral / bacterial infection
   Exercise
2. Drugs
   Beta-blockers
   Non-steroidal anti-inflammatory drugs

3) Cold air and scents

Question 2

3 phase disorder

Answer 2

Smooth muscle only – triggered by direct mediator release eg histamine – rare wheezy episodes

Chronic Inflammation – irritates the smooth muscle and causes regular wheezy episodes

Acute Inflammation – viral infection – ‘clinical exacerbations’

Question 3

inflammation

Answer 3

Inflammation leads to tissue repair and return of normal organ function

Network of cells and chemical signals (cytokines, prostaglandins, leukotrienes, immunoglobulins) carefully regulated

In an abnormal organ (eg asthmatic airways) or in the wrong place inflammation can cause harm

Question 4

type 2 inflammation

Answer 4

Cells – lymphocytes, eosinophils and mast cells

Cytokines – IL-4, IL-5

Prostanoids – PGE2, Leukotriene D4

Immunoglobulins – specific IgE (eg House dust mite)

Question 5

pathophysiology of asthma

Answer 5

Inflammatory disease of the medium sized airway
Associated with:

Loss of airway epithellium
Thickening of the basement membrane

Hypertrophy of the smooth muscle layer

Resulting in:
Hyper-responsiveness to normal triggers of contraction

Abnormal contraction in response to usually benign triggers

Question 6

presentation of asthma

Answer 6

Bronchospasm – tightening of the smooth muscle mesh surrounding the airway:
WHEEZE, DYSPNOEA, EXERCISE INTOLERANCE
Inflammation –
COUGH

Question 7

management of asthma

Answer 7

Bronchorelaxation – beta2 Agonists
Anti-inflammatories – corticosteroids, leukotriene receptor blockade, monoclonal antibodies

Question 8

airway resistance- maintains flow of air

Answer 8

In absence of airway wall tension, air would simply compress due to low viscosity

Question 9

ways of narrowing an airway

Answer 9

Dynamic:
Rapid muscle contraction
Medium – secretions

Fixed: Stiff airway wall
Smooth muscle bulk
Thickened basement membrane

Question 10

pathology of asthma

Answer 10

Weakened and ‘denuded’ airway epithelium
Thickened BM
Increased Smooth Muscle
Mast cells in Smooth Muslce

Question 11

beta- 2 - agonist

Answer 11

β-2 adrenergic (adrenaline) receptor or 7 Trans-membrane units (7TM) activates G-protein –>

cyclic AMP - second messenger–> relaxes smooth muscle widening the airway