Conditions

Question 1

Pathophysiology of asthma

Answer 1

Chronic, inflammatory and reversible airway obstruction that causes a hypersensitive immune response in the small airways due to exposure to a trigger

• Bronchospasm: Contraction of smooth muscle
• Engorgement and swelling of the bronchioles: inflammation and reduction of airway diameter
• Mucous production: Hyperinflation and air-trapping

Question 2

What is atopy?

Answer 2

It is a genetic tendency to develop allergies (hx of allergic disease in the first degree relative)

Question 3

What are the 2 main groups of asthma triggers?

Answer 3

1. Extrinsic

2. Intrinsic

Question 4

What are 3 types of extrinsic asthma triggers?

Answer 4

• Pollen
• Dust mites
• Mould

Question 5

What are 3 types of intrinsic asthma triggers?

Answer 5

• Viruses
• Anxiety
• Stress

Question 6

Explain the asthma triad

Answer 6

1. Cough
   - Inflammation and mucous in the airways stimulates a cough reflex
2. Dyspnoea
   - Airway narrowing on expiration resulting in gas trapping and hyperinflation of the lungs = working harder to ventilate
3. Wheeze
   - Airway narrowing increases velocity of airflow
4. Chest tightness
   - Hyperinflation of the lungs

Question 7

What is V/Q (ventilation/perfusion)

Answer 7

The V/Q ratio is the amount of air that reaches your alveoli divided by the amount of blood flow in the capillaries in your lungs

Question 8

What is a V/Q mismatch?

Answer 8

A mismatch happens when part of your lung receives oxygen without blood flow or blood flow without oxygen, caused by an obstructed airway or blood vessel. A mismatch can cause hypoxaemia (low levels of o2 in the bloodstream)

Question 9

Lung volumes of children

Answer 9

Children have a smaller functional residual capacity (FRC)-outward pull of the chest wall equals inward collapse of the lung, thereby a smaller respiratory reserve.
-Decreased time before respiratory failure/atelectasis

Question 10

What is croup

Answer 10

A viral infection of the upper airway that results in upper airway obstruction as a result of swelling to the larynx, trachea and large bronchi due to infiltration of white blood cells

Question 11

Pathophysiology of croup

Answer 11

The narrowest part of the child’s airway is the subglottic region surrounded by cartilage. Inflammation at this site and oedema restricts airflow due to narrowing in the airway causing inspiratory stridor, swelling of the vocal chords (hoarse voice) and a barking cough

Question 12

Aetiology of croup

Answer 12

• Parainfluenza 1,2,3 (75% of cases)
• RSV
• Influenza A, B + adenovirus

Question 13

What is the tetrad of symptoms related to croup?

Answer 13

• Hoarse voice
• Barking cough
• Inspiratory stridor
• Respiratory distress

Question 14

What is bronchiolitis and it’s pathophysiology?

Answer 14

It is the inflammation of the lining of the epithelial cells of the bronchioles (lower airways of the lungs), most commonly as a result of RSV.
Results in:
-Increased mucous production
-Inflammation
-Cellular necrosis

Question 15

What is respiratory failure?

Answer 15

Occurs when the lungs are unable to deliver adequate oxygen to arterial blood and remove carbon dioxide at a rate that matches the body’s metabolic demand

Question 16

What is intrapulmonary shunting??

Answer 16

Alveoli remain perfused but pulmonary blood flow does not participate in gas exchange because the perfused lung receives no ventilation.