Infectious Croup

Anesthesia Implications

Anesthesia Implications

Subglottic narrowing – If the patient has had more than two cases of croup requiring hospitalization, evaluation should be made to determine if there’s been subglottic narrowing.

Intubation – Rarely indicated when treating this condition.

Humidified air/oxygen – The majority of croup cases resolve with humidified air/oxygen. This prevents drying of secretions.  Hydration will also aid in this objective.

Nebulized racemic epinephrine – very effective in treating emergent cases of croup (eg 0.5 mL of a 2.25% solution in 2.5 mL normal saline).

Corticosteroid treatment – Evidence suggests that corticosteroid treatment (eg. Decadron 0.5 – 1.0 mg/kg IV) leads to significant improvement over 12-24 hours, which will markedly reduce the need for endotracheal intubation.

Pathophysiology

This condition is due to subglottic mucosal irritation and swelling. There are two forms: Viral and spasmodic

Viral laryngotracheal bronchitis is croup WITH a fever (low-grade or otherwise). This form is the most common (97% of cases) and usually follows a viral upper respiratory infection.

Spasmodic croup is croup WITHOUT a fever and severe subglottic swelling. This form is uncommon (3% of cases)

Croup is characterized by a complex stridor. Stridor suggests inspiratory problems – so accompanying symptoms include substernal, intercostal, and suprasternal retractions on inhalation.

Croup is characterized by gradual onset. The most notable sign is the “barking” cough and hoarseness.

Radiographs made anteroposteriorly will show the “steeple” sign. Radiographs made laterally will appear normal.

A common differential diagnosis is epiglottitis. The differences have been outlined in the table below

Additional Notes:

Croup Epiglottitis
Ages < 3 years > 3 years
Affected area Subglottic Supraglottic
Etiology Viral Bacterial
Onset Gradual (days) Rapid (hours)
Fever none or low grade high
Radiographs Steeple Thumb
Airway Support Rarely Always
References

Cote. Practice of anesthesia in infants and children. 4th edition. 2009. p. 42, 60, 253, 675-676
Butterworth. Morgan & Mikhail’s Clinical Anesthesiology. 2013. p. 902