Laryngotracheobronchitis, Acute Viral (Croup)

Description

Diagnostic criteria

General and supportive measures

Medicine treatment

Referral

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ICD-10 code: J05.0

DESCRIPTION

Potentially life-threatening airway obstruction in children and one of the most common causes of stridor in children aged between 6 months and 2 years.
The most important viruses causing laryngotracheobronchitis (LTB) include:

• para-influenza virus (most common),
• measles,
• herpes simplex,
• adenovirus.

DIAGNOSTIC CRITERIA

Clinical

• A previously healthy child who, a day or two after the onset of an upper respiratory tract infection, develops progressive airway obstruction with a barking cough and stridor.
• A mild fever may be present.
• Stridor becomes softer as airway obstruction becomes more severe.

The following features suggest a different diagnosis:

• acute onset of obstruction without prodromal features (foreign body or angioneurotic oedema),
• incomplete immunisation and a membrane in the upper airway (diphtheria),
• high fever, dysphagia, drooling or sitting position (epiglottitis, retro-pharyngeal abscess, bacterial tracheitis),
• recurrent upper airways obstruction (laryngeal papilloma).

Assessment of severity of airway obstruction in LTB

Severity	Inspiratory obstruction (Stridor)	Expiratory obstruction (Stridor)	Pulsus paradoxus
Grade 1	+
Grade 2	+	+ passive expiration
Grade 3	+	+ active expiration using abdominal muscles	+
Grade 4	cyanosis, apathy, marked retractions, impending apnoea

GENERAL AND SUPPORTIVE MEASURES

• Monitor the nutritional status and fluid requirements.
• Monitor oxygen saturation, heart rate and respiratory rate.
• Avoid arterial blood gas estimations. Clinical criteria are more effective in determining severity.
• Depending on severity, admit child to high care or intensive care ward.

MEDICINE TREATMENT

Grade 1 obstruction

• Prednisone, oral, 2 mg/kg as a single dose.
  • To a maximum of:
    • 20 mg: Children < 2 years for 5 days.
    • 30 mg: Children 2–5 years for 5 days.
    • 40 mg: Children 6–12 years for 5 days

OR

• Dexamethasone, IV/IM, 0.5 mg/kg as a single dose.

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Note:
Avoid steroids in patients with measles or herpes infection.

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Grade 2 obstruction
As above

PLUS

• Adrenaline (epinephrine), 1:1000, nebulised with oxygen, every 15–30 minutes until expiratory obstruction is abolished.
  • 1 mL adrenaline (epinephrine) 1:1 000 diluted in 1 mL sodium chloride 0.9%.

Grade 3 obstruction
As above:

• if improvement, treat as in grade 2 but reduce frequency of adrenaline (epinephrine) nebulisations with time,
• if no improvement within 1 hour, intubate, preferably under general anaesthetic,
• refer.

Grade 4 obstruction
As above and:

• continue steroids,
• continue with adrenaline (epinephrine) nebulisation with 100% warm humidified oxygen,
• emergency intubation or intubation under general anaesthesia, if circumstances permit,
• if unable to intubate, bag and mask ventilate and refer urgently.

For suspected herpes:

• Aciclovir IV, 10–15 mg/kg/dose 8 hourly for 5–7 days.

For suspected bacterial infection in children:

• Amoxicillin/clavulanate, IV, 25 mg/kg/dose of amoxicillin component 8 hourly (do not exceed 10 mg/kg/day of clavulanate component) for 7 days.

REFERRAL

• Intubated children for ICU care. Intubate all children with grade 3 airway obstruction not responding to adrenaline nebulisations and all children with grade 4 airway obstruction before referral.
• Children with an uncertain diagnosis.

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Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Paediatrics, 2023 Edition

Chapter 15: Respiratory System,  15.5 Upper Airway Diseases,  15.5.2 Laryngotracheobronchitis, Acute Viral (croup)