Asthma Flashcards

1
Q

Definition of asthma

A

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

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2
Q

What are the 2 types of asthma?

A

Allergic (70%)
Non allergic (30%)

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3
Q

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

A

IgE mediated, EXTRINSIC, T1 hypersensitivity

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

Consider genetics and HYGIENE HYPOTHESIS

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4
Q

What is hygiene hypothesis?

A

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

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5
Q

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

A

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

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6
Q

Triggers of asthma?

A

Infection
allergens
cold weather
exercise
drugs (BB, aspirin)

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7
Q

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

A

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

Too many TH2 cells in all 3

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8
Q

What is Samter’s triad?

A

Nasal Polyps
Asthma
aspirin sensitivity

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9
Q

What is aspirin sensitivity?
How does it affect asthma?

A

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

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10
Q

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

A

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

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11
Q

What happens over time to the bronchus?

A

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

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12
Q

Sx of asthma?

A

Wheeze, dry cough, chest tightness, SOB

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13
Q

What may microscopy of mucus show?

A

Curschmann spirals and Charcot leyden crystals

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14
Q

How often do asthma attacks occur and why?
age?

A

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

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15
Q

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

A

Moderate - PEF 50-75%

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

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

Fatal - hypercapnia, pKa 6+

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16
Q

Dx of asthma?

A

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

17
Q

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

A

Reversible when >12% FEV1 increased = Asthma

Irreversible when <12% FEV1 increased = COPD

18
Q

Tx for asthma?

A
  1. SAB2A
  2. SAB2A + ICS
  3. SAB2A + ICS + LTRA
  4. SAB2A + ICS + LAB2A +/- LTRA
  5. increase ICS dose
19
Q

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

A

Salbutamol
salmeterol
ipatropium bromide
tiotropium bromide

20
Q

For exacerbations, what’s the acronym?

A

OSHITME

21
Q

What does OSHIT me stand for?

A

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

22
Q

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

A

CPAP/BIPAP
For asthma = always BIPAP

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