Asthma

Question 1

Definition of asthma

Answer 1

Chronic reversible airway disease characterised by
REVERSIBLE AIRWAY OBSTRUCTION + AIRWAY HYPERRESPONSIVENESS +
INFLAMED BRONCHIOLES
and mucous hypersecretion

Question 2

What are the 2 types of asthma?

Answer 2

Allergic (70%)
Non allergic (30%)

Question 3

What is allergic asthma?
What is it due to?
What should we consider with allergic asthma?

Answer 3

IgE mediated, EXTRINSIC, T1 hypersensitivity

Due to environmental triggers (pollen, dust, mould, antigens) - often present early eg. in children

Consider genetics and HYGIENE HYPOTHESIS

Question 4

What is hygiene hypothesis?

Answer 4

decreased exposure to pathogens at a young age can increase TH2 response and susceptibility to asthma infection

Question 5

What is non allergic asthma?
When may it present?
Trigger?

Answer 5

Non IgE mediated, INTRINSIC
May present later, harder to treat, associated with smoking (or perfumes) - like COPD

Question 6

Triggers of asthma?

Answer 6

Infection
allergens
cold weather
exercise
drugs (BB, aspirin)

Question 7

What is the atopic triad?
What is this triad caused by?

Answer 7

Atopic rhinitis (nasal dryness)
Asthma
Eczema
(some people have these 3 synonymously, known as ATOPY)

Too many TH2 cells in all 3

Question 8

What is Samter’s triad?

Answer 8

Nasal Polyps
Asthma
aspirin sensitivity

Question 9

What is aspirin sensitivity?
How does it affect asthma?

Answer 9

Aspirin inhibits COX-1/2 therefore shunts more arachidonic acid down LPOx pathway which produces leukotrienes LT B4,5,6 = Proinflammatory

Question 10

What is the pathology of the early phase (mins) from TH2 cells to bronchial constriction?

Answer 10

Overexpressed (too many) TH2 cells in airway exposed to trigger

TH2 cytokine release IL3,4,5,13 which produce IgE production and eosinophil recruitment

IgE mast cells degranulate and release : Histamines, leukotriene, try-take
Eosinophils release toxic protein eg. MBP

Causes bronchial constriction and mucus hypersecretion

Question 11

What happens over time to the bronchus?

Answer 11

Chronic remodelling (irreversible)
Bronchial scarring = lower lumen size = lots of mucus

Question 12

Sx of asthma?

Answer 12

Wheeze, dry cough, chest tightness, SOB

Question 13

What may microscopy of mucus show?

Answer 13

Curschmann spirals and Charcot leyden crystals

Question 14

How often do asthma attacks occur and why?
age?

Answer 14

Typically episodic with trigger and diurnal (day) variation
often younger Px

Question 15

What 4 categories are episodes classed as and what is the PEF for each?

Answer 15

Moderate - PEF 50-75%

Severe - PEF 33-50% - can’t finish sentences

Life threatening - PEF <33% - decreased consciousness, silent chest

Fatal - hypercapnia, pKa 6+

Question 16

Dx of asthma?

Answer 16

Spirometry
High FeNO
Spirometry shows obstruction (FEV1:FVC <0.7)

Question 17

After bronchodilator administered, what values mean it is reversible and irreversible and the diseases behind each one?

Answer 17

Reversible when >12% FEV1 increased = Asthma

Irreversible when <12% FEV1 increased = COPD

Question 18

Tx for asthma?

Answer 18

1. SAB2A
2. SAB2A + ICS
3. SAB2A + ICS + LTRA
4. SAB2A + ICS + LAB2A +/- LTRA
5. increase ICS dose

Question 19

What are examples of a drug of the class…
SABA
LABA
SAMA
LAMA

Answer 19

Salbutamol
salmeterol
ipatropium bromide
tiotropium bromide

Question 20

For exacerbations, what’s the acronym?

Answer 20

OSHITME

Question 21

What does OSHIT me stand for?

Answer 21

O2
nebulised Saba
ics Hydrocortisone
IV MgSO4 (bronchodilator)
IV Theophylline
MgSO4 IV
Escalate

Question 22

What else could be done if breathing is bad, exacerbation?

Answer 22

CPAP/BIPAP
For asthma = always BIPAP

+/- Abx if infection present
viral infection = common trigger