Asthma

Question 1

Asthma definition

Answer 1

Chronic, episodic inflammatory disorder

Asthmatics have sensitive, inflamed and irritable airways which reacts to triggers

Extrinsic and intrinsic asthma

Question 2

What is extrinsic asthma

Answer 2

Allergic asthma
Most common type

Triggered by allergens

Process initiated by Type 1 hypersensitivity reaction

• mast cells
• macrophages

Inflammatory response abnormally regulated by inflammatory mediators

Question 3

Describe First exposure

Answer 3

Allergen enters body
B cell detects allergen
IgE production in response
IgE attachment to mast cell.

Question 4

describe second exposure to allergen

Answer 4

Mast cell made from first exposure has allergen-specific IgE

Exposure to allergen

Allergen attachment to IgE and degranulation of mast cell

Question 5

Patho of asthma

Answer 5

Inflammatory response leads to 
Bronchoconstriction 
Increased mucus production 
Vasodilation 
Oedema 

Leading to
Hyperresponsiveness
Airflow limitation
Respiratory symptoms

• force required to deflate lungs is increased exponentially as lungs inflate
• takes more energy to ventilate at the top of vital capacity

Question 6

Chronic changes to airways asthma

Answer 6

Inflammatory cell infiltration
- excessive populations of eosinophils and neutrophils in asthmatic airway

Structural changes

• increased amounts of smooth muscle, collagen and mucous calls
• increases the bulk and therefore pressure on lumen - remodeling airway

Question 7

What is gas trapping

Answer 7

Narrow airways collapse as the chest wall relaxes and the intra- thoracic pressure increases in exhalation which traps air

Also involves dyssynchrony of the muscles due to fatigue

Question 8

Asthma signs and symptoms

Answer 8

Episodic or chronic pattern

Increased resp rate with prolonged expiratory phase

Wheezing, SOB, Chest tightness

Cough
Increased work of breathing

Anxiety
Hypoxia

Question 9

Describe SNS response

Answer 9

Hypoxia leads to SNS response

Tachycardia, hypertension, respiratory acidosis

Which leads to 
Dizziness 
Cyanosis 
Decreased LOC 
Respiratory Arrest 
Cardiac Arrest

Question 10

Describe the classifications of asthma

And typical signs of each

Answer 10

Mild

• breathless but not distressed
• PEFER reduces but still >75%
• sentences
• <100bpm hr

Moderate

• PEFER >50%
• phrases
• 100-120 bpm hr

Severe

• too breathless to talk/feed
• resp rate >20 or <8
• words
• 120> bpm hr

Life threatening

• PEFER <33% normal
• silent chest and cyanosis
• fatigue, drowsiness, confusion
• Hypotension

Question 11

Describe severe/ life threatening asthma

Answer 11

Severe

• too breathless to talk/feed
• resp rate >20 or <8
• words
• 120> bpm hr

Life threatening

• PEFER <33% normal
• silent chest and cyanosis
• fatigue, drowsiness, confusion
• Hypotension

Question 12

Describe typical signs of mild/moderate asthma

Answer 12

Mild

• breathless but not distressed
• PEFER reduces but still >75%
• sentences
• <100bpm hr

Moderate

• PEFER >50%
• phrases
• 100-120 bpm hr

Question 13

Patient assessment questions for asthma

Answer 13

• what triggers cough/wheeze
• recent URTI?
• how many acute attacks? How severe?
• have you been to ICU? Intubated?
• how often do you use your reliever?
• is it getting better or worse?
• other symptoms?

Question 14

PASSERPS FOR ASTHMA?

Answer 14

Position 
Appearance 
Speech 
Sounds 
Rate and rhythm 
Effort 
State of consciousness 
Pulse 
Skin

Question 15

Breath sounds in asthma where/what to listen to

Answer 15

- compare lobes 
Listen for 
Intensity 
Pitch 
Duration
Quality

Question 16

What does adventitious breath sounds involve

Answer 16

Predicts presence/absence of air entry

• wheezes
• crackles
• stridor
• rubbing

Rhythm is air entry
- inspiratory vs expiratory

Question 17

What is the I:E ratio

Answer 17

1:2 normally

Question 18

Respiratory pharmacology- bronchodilators

Answer 18

Adrenaline, salbutamol

Beta agonists stimulate beta adrenergic receptors on bronchial smooth muscle

Question 19

Respiratory pharmacology

- Anticholinergic agents

Answer 19

Ipratropium Bromide

Block muscarinic cholinergic receptors on bronchial smooth muscle

Question 20

Respiratory pharmacology-

Methylxanthines

Answer 20

Aminophylline

• elevate intracellular messenger cAMP to moderate cellular activity

Question 21

Respiratory pharmacology

- Corticosteroids

Answer 21

Oral prednisolone
IV hydrocortisone
Dexamethasone

Provide a systemic response

Question 22

Salbutamol pharmacology

Answer 22

Stimulates beta 2 receptors on bronchial smooth muscle resulting in bronchodilation

5mg via Neb whilst indicated

Question 23

Ipratropium Bromide

Answer 23

Anticholinergic bronchodilator

Bronchodilator
Blocks vagal reflexes which mediate bronchoconstriction

Synergistic when used with salbutamol

Contraindications
Allergy
Glaucoma~

500mcg via neb with salbutamol max 2 doses

Question 24

Adrenaline for asthma

Answer 24

Alpha beta stimulation

500mcg 1:1000 IM bolus in lateral aspect of thigh

Every 5min no max

Question 25

Hydrocortisone pharmacology

Answer 25

Corticosteroid 100mg vial reconstituted with 2ml saline. IM or IV just ^. Max 100mg Contraindications Allergy Uncontrolled infection Active peptic ulcer disease