Resp - Virally Induced Wheeze

Question 1

Definition

Answer 1

Episodic wheeze - a symptom of viral URTI and common in preschool children up to 5 years old.
- Most common virus with wheezing in children include RSV, rhinovirus, and influenza viruses

Question 2

Epidemiology

Answer 2

Under 5
Hereditary element
More likely to develop asthma later in life

Question 3

Aetiology

Answer 3

RSV
Rhinovirus

Question 4

Pathophysiology (clue: similar to bronchiolitis)

Answer 4

Children have small airways
When encounter virus - leads to inflammation and oedema
Swelling of airways restricts space for airflow
Inflammation also triggers smooth muscles of airways to constrict = even more narrow
Air flowing through these narrow airways causes wheeze = restricted ventilation = respiratory distress

Question 5

3 defining factors of virally induced wheeze

Answer 5

Presenting before 3 years of age
No atopic history
Only occurs during viral infections

Question 6

Signs and symptoms

Answer 6

Evidence of a viral illness (fever, cough and coryzal symptoms) for 1-2 days preceding the onset of:

Signs:
- Tachypnoea
- Widespread wheeze on auscultations
- Respiratory distress
- Evidence of URTI e.g hyperaemic tonsils

Symptoms:
- Coryza
- Cough and wheeze
- Difficulty in breathing
- Poor feeding
- Fever

Question 7

NEITHER VIW OR ASTHMA CAUSES FOCAL WHEEZE

Answer 7

THINK:
- FOCAL AIRWAY OBSTRUCTION
- TUMOUR

Question 8

Diagnosis

Answer 8

Clinical diagnosis
Investigations to consider:
- PEFR
- Chest X ray
- Capillary blood gas

Question 9

Management

Answer 9

Oxygen
Bronchodilators:
- FIRST LINE = SABA
- SECOND LINE = Antimuscarinic e.g. ipatropium bromine
Ventilation

Question 10

Prevention in children with recurrent wheeze

Answer 10

Corticosteroids
- trial of Inhaled corticosteroids considered when there is FHx of asthma
- trial of oral corticosteroids considered when child has had episode requiring admission
Leukotriene antagonists: MONTELUKAST

Question 11

Complications

Answer 11

Respiratory failure
Asthma