Croup (Laryngotracheobronchitis)

Notes

## Basic introduction

  • It is a clinical syndrome that is caused by viral infection and characterized by the inflammation of the larynx and trachea.
  • Occurs mostly after URTI
  • It mainly affects children < 3 years
  • Usually worse in the late evening and at night

## Causes of croup

  • Parainfluenza virus type 1 infection (about 80% of all cases)
  • Adenoviruses
  • Enteroviruses
  • Influenza A and B
  • Measles
  • Metapneumovirus
  • Respiratory syncytial virus
  • Rhinoviruses
  • Mycoplasma pneumoniae

## Pathophysiology

  • There is infection that causes inflammation of the larynx, trachea, bronchi, bronchioles, and lung parenchyma
  • The resultant swelling and inflammatory exudates cause obstruction that is more prominent in the subglottic region
  • This obstruction increases breathing workload and it can cause hypercapnia and atelectasis

## Risk factors

  • Previous admissions with severe croup
  • Pre-existing narrowing of upper airways in subglottic stenosis and Down Syndrome (among others)

## Statistics

  • Symptoms in most cases resolve within 48hrs.
  • About 5% of children in UK have croup during the second year of life.
Symptoms
  • Brassy, barking cough
  • Inspiratory stridor
  • Fever
  • Hoarse voice
  • May have associated widespread wheeze
  • Irritability
  • Rapid breathing and lower chest indrawing (in severe croup)
  • Cyanosis
  • Oxygen saturation ≤ 90%
Diagnosis
  • Clinical review. (Due to the risk of inducing laryngeal spasm and/or total airway obstruction, examination of the pharynx and larynx should be tried in a facility with equipment and staff prepared for possible intervention)
  • Extensive investigations such as CXR and blood tests are ONLY done when it is extremely necessary as they may cause distress and worsening of symptoms
  • Pulse oximetry in case of moderate to severe croup (NOT in mild cases)
Differential
  • Epiglottitis
  • Acute anaphylaxis
  • Angioneurotic oedema
  • Bacterial tracheitis
  • Diphtheria
  • Inhaled foreign body
  • Inhaled noxious substance
  • Laryngomalacia
  • Peritonsillar abscess
  • Retropharyngeal abscess
  • Vocal cord paralysis
  • Burns
  • Congenital anomaly
Prevention
  • There is no definite preventive measure
  • Encourage hand washing
Reference
  1. World Health Organization. (2005). Pocket book of hospital care for children: guidelines for the management of common illnesses with limited resources. World Health Organization.
  2. Kenyan Ministry of Health. Clinical guidelines for management and referral of common conditions at levels 4-6. Hospitals. 2009; 3:259-261.http://apps.who.int/medicinedocs/documents/s21000en/s21000en.pdf

Ministry of Health, Kenya. Kenya Essential Medicine List (2016). http://publications.universalhealth2030.org/uploads/KEML-2016Final-1.pdf

Management

## Mild croup

  • Mild croup can be managed at home
  • Breastfeeding
  • Oral fluids

## Severe croup

  • The child must be admitted for treatment
  • Antipyretics
  • Hydration
  • Nebulized racemic epinephrine (2mL of 1:1000 that may be given hourly)
  • Corticosteroid therapy:

_Tabs Dexamethasone: children: 0.08 to 0.3 mg/kg/day in divided doses every 6-12 hours. Adults: 0.75 to 9 mg/day in divided doses every 6-12 hours.

_Other corticosteroids at equivalent dose can be used

  • Airway protection such as nasotracheal intubation or tracheotomy / cricothyrotomy in case of severe croup that is worsening
  • Supplemental oxygen in case of apparent near complete airway obstruction
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