Viral Induced Wheeze

Question 1

What is Viral Induced Wheeze?

Answer 1

• Acute wheezy illness caused by a viral infection which affects small children with small airways (typically under the age of 3)

Question 2

Which organism typically causes Viral Induced Wheeze?

Answer 2

• RSV
• Rhinovirus

Question 3

What is the Pathophysiology of Viral Induced Wheeze?

Answer 3

• When the small airways encounter a virus, they undergo inflammation and oedema
• The inflammation causes smooth muscle constriction
• This causes swelling of the airway walls and restricted airflow
• This affects children more than adults due to Poiseuille’s Law: states flow rate is proportional to the radius of the tube to the power of four
• Air flowing through these narrow airways causes a wheeze
• Restricted Ventilation leads to Respiratory Distress

Question 4

What are the Risk factors for Viral Induced Wheeze?

Answer 4

• Family History

Question 5

How does Viral Induced Wheeze Present?

Answer 5

• Fever, Cough and Coryzal Symptoms for 1/2 days
• SOB
• Respiratory Distress
• Expiratory Wheeze throughout the chest / not a focal wheeze

Question 6

The difference between Viral Induced Wheeze and Asthma?

Answer 6

• Viral Induced Wheeze Features:
  Presenting before 3 years of age
  No atopic History
  Only occur during Viral Infections

Question 7

What is the management for Viral Induced Wheeze?

Answer 7

Moderate: - nebulised SABA (salbutamol 5mg), nebulised ipratropium bromide, Steroids: oral Prednisolone/ IV hydrocortisone for 5 days, Anti-biotics

Severe: - Oxygen for sats 94%-98%, Aminophylline Infusion, IV salbutamol

Life- threatening: - IV magnesium sulphate infusion, Admission to HDU/ ICU, Intubation