Resp - Bronchiolitis

Question 1

Definition

Answer 1

inflammation and infection in the bronchioles, the small airways of the lungs most commonly caused by respiratory syncytial virus

Question 2

Epidemiology

Answer 2

Under 1 - peak incidence of 3-6 months
Very common
Peaks in winter and spring
Most common cause = Respiratory syncytial virus

Question 3

Risk factors

Answer 3

Breast feeding < 2 months
Prematurity
Smoke exposure
Chronic lung disease of prematurity
Congenital heart disease e.g. patent ductus arteriosus
Higher incidence in winter

Question 4

Pathophysiology

Answer 4

As the epithelial cells lining the small airways become inflamed, excess mucus is produced and cellular necrosis of these cells occurs. It is this inflammation that obstructs the small airways and ultimately results in wheezing and difficulty in breathing.

Question 5

Trajectory of 9 days

Answer 5

• Initially: URTI and Coryza and cough
• Day 3: the infection spreads, causing inflammation of the bronchioles and increased work of breathing
• Day 5: severity peaks
• Day 5-9: recovery period

Question 6

Signs

Answer 6

• Increased work of breathing
  = tachypnoea
  = reduced oxygen saturation
  = grunting or nasal flaring
  = subcostal or intercostal recession
  = tracheal tug
• Crackles (not always present) +/or wheeze
• Pyrexial (usually < 40 deg)
• Tachycardia
• Dehydration
  = dry nappy
  = dry mucous membranes
• Apnoea

Question 7

Symptoms

Answer 7

• Coryzal symptoms
  = snotty nose
  = sneezing
  = mucus in throat
  = watery eyes
• Cough and wheeze
• Mild fever
• Difficulty breathing
• Reduced feeding

Question 8

Diagnosis

Answer 8

Clinical diagnosis based on history and examination
- Nasopharyngeal aspirate
- Capillary blood gas
- Chest x-ray - only really done when suspected superimposed bacterial infection
- Throat swab

Question 9

Management

Answer 9

Largely supportive treatment:
- O2 supplements
= if SpO2 < 90% for children aged 6weeks +
= SpO2 < 92% if children are less than 6 weeks old
- Upper airway suctioning
NOTE: Abx, bronchodilators, steroids, and hypertonic saline = NOT RECOMMENDED in Bronchiolitis

Supportive care:
- Oral feeds: if able to suck and not distressed
- NG feeds: if not tolerating oral feeds or less than 50% or tackypnoic
- IV fluids: if severe RD or not tolerating NG feeds

Question 10

Prophylaxis

Answer 10

Prophylaxis = PALIVIZUMAB is monoclonal antibody given to infants at high risk for severe infection
Indications include:
- Chronic lung disease: children < 9 months born preterm
- Respiratory diseases
- Congenital heart disease: children < 6 months with haemodynamically significant acyanotic CHD born pre-term
- Severe combined immunodeficiency syndrome
As of September 2024, pregnant women can take an RSV vaccine from 28 weeks gestation onwards

Question 11

Types of O2 supplementation

Answer 11

• This is a step up order in increasing severity of SpO2 + RD *
  Headbox: humidified oxygen
  Nasal cannulae: can deliver high flow humidified oxygen (optiflow)
  CPAP/ventilation: indicated if there is evidence of severe respiratory distress

Question 12

Admission

Answer 12

Reasons for admission:
- Apnoea
- Persistent oxygen saturation (when breathing air)
= Child aged 6 weeks + < 90%
= Child aged less than 6 weeks < 92%
- Inadequate oral fluid intake
- Persisting severe respiratory distress, e.g. grunting, marked recession, or respiratory rate of over 70 breaths/minute