Why do Infants Wheeze

Question 1

What is the definition of a wheeze

Answer 1

• Musical lung sound caused by oscillations in narrowed airways

Question 2

what does the frequency of a wheeze depend on

Answer 2

• degree of narrowing
• elasticity of airway wall
• local airflow

Question 3

what generates the wheeze

Answer 3

• generated by the smaller airways oscillating

Question 4

Is a wheeze usually expiratory or inspiratory

Answer 4

• Almost always expiratory clinically, might have an inspiratory component as well but it is very rare to get a pure inspiratory wheeze

Question 5

What sounds can wheeze have

Answer 5

• Squeaky or whistling noises
• Wet rattly noises
• Both whistling and ratty noises

Question 6

What type of airways generate wheeze

Answer 6

• smaller airways generate wheeze

Question 7

What happens if there is a

• Slight narrowing
• greater narrowing

Answer 7

Slight narrowing

• velocity increases
• pressure decreases

greater narrowing

• velocity decreases
• pressure increases

Question 8

What are two types of wheezes that you can have

Answer 8

• expiatory wheeze

- inspiratory wheeze

Question 9

what causes an expiatory wheeze

Answer 9

Narrowing of the intrathoracic airways causes an expiratory wheeze

Question 10

What causes an inspiratory wheeze

Answer 10

Narrowing of the extra thoracic airways causes an inspiratory wheeze

Question 11

what would you hear in an inspiratory wheeze

Answer 11

• you wouldn’t hear anything in the chest that sounded like a wheeze vocally a wheeze in comparison in an expiratory wheeze can be hear in the chest as it is the intrathoracic airways that are narrowing
• intrathoracic airways expand so wheezing not usually heard (unless severe).

Question 12

which age group is wheeze common in

Answer 12

 episodes of wheeze are common in preschool children (10 mo to 6 yr)

Question 13

how many people wheeze before 3 years

Answer 13

 35% will wheeze at least once before 3 yr

Question 14

what is wheezing usually triggered by in preschool children

Answer 14

 attacks usually triggered by colds

 few or no symptoms between attacks

Question 15

What are the preschool wheeze risk factors

Answer 15

• smoking in pregnancy – risk factor as maternal smoking alters the airway structures
• air pollution – new onset preschool wheeze significantly associated with pollution at home-school address - more vulnerable to develop viral infections or it could affect the lung growth
• younger mother?

Question 16

name the three types of preschool wheezers

Answer 16

• transient early wheezes
• non atopic wheezers
• IgE associated wheeze/asthma

Question 17

Describe transient early wheezers

Answer 17

• wheeze between first and 3 years of age
• stop wheezing by 3 years
• due to being born with low lung function and the tendency to develop hyperactive airways with colds
• have normal lung function by the age of 11

Question 18

describe non atopic wheezes

Answer 18

• between the ages of 3-6
• later onset but not all resolves
• starts with a symptomatic lower respiratory tract infection such as (RSV, bronchitis)
• continues to wheeze beyond their third year
• most outgrow condition but if not they will progressively lose lung function over time

Question 19

less than 1/3 of wheezing infants…

Answer 19

• Less than 1/3 of wheezing infants will develop recurrent wheezing later in life (atopic asthma)

Question 20

what does atopy mean

Answer 20

o Atopy = predisposition toward developing certain allergic hypersensitivity reactions

Question 21

describe airway inflammation in preschool wheeze presentation

Answer 21

• No inflammation between attacks

* Pattern of inflammation between attacks unknown.

Question 22

describe what atopic asthma in older children looks like

Answer 22

 Wheeze between colds

 Wheeze attacks triggered by colds

Question 23

describe what the airways of children with atopic asthma look like

Answer 23

 persistent inflammation throughout central and peripheral airways
 denudation of airway epithelium
 infiltration of lymphocytes and eosinophils

Question 24

describe at a cellular level the differences between asthmatics lungs and non asthmatics lungs

Answer 24

Normal:
• Epithelium intact.
• No thickening of sub-basement membrane
• No cellular infiltrate.

Asthmatic:
• Goblet cell hyperplasia.
• Thick subbasement membrane.
• Cellular infiltrate.

Question 25

what is the preschool wheeze treatment

Answer 25

• Mild intermittent asthma = short acting beta 2 agonists
• Regular preventer therapy = ICS or LTRA if steroid cannot be used
• Inhaled add on therapy – add LTRA or inhaled steroid if on LTRA alone
• Refer to a respiratory paediatrician

Question 26

what is the delivery device used in children

Answer 26

• have to reduce the distance between the puffer and breathing in therefore you use spacers

Question 27

what can be used for differential diagnosis for preschool wheeze

Answer 27

• structures that cause wheeze like illness such as bronchogenic cysts, hyperinflamation of the entire left upper lobe, congenital lobar emphysema,

Question 28

describe what bronchogenic systems look like

Answer 28

 thin walled with ciliated columnar lining
 may contain cartilage, smooth muscle
 some have gastro-oesophageal mucosa
 air or fluid filled

Question 29

describe how bronchogenic cysts present

Answer 29

o Early with respiratory distress.
o Later with infection.
o (Or) asymptomatic.

Question 30

what are the treatment are bronchogenic cysts

Answer 30

surgical removal

Question 31

describe congenital lobar emphysema

Answer 31

• Over distension of lobe
• Partial bronchial obstruction
• Ball valve effect.