Synonyms: Acute laryngotracheal bronchitis, Viral laryngotracheal bronchitis
Introduction: This clinical syndrome is characterized by Hoarseness of voice, stridor (inspiratory / biphasic), barking cough.
This is caused by mucosal oedema of larynx and trachea. These patients will give h/o symptoms of upper respiratory tract infections
associated with fever and malaise. This condition is classically caused by parainfluenza type I virus. Other viruses that can cause
this condition include Parainfluenza type II, Respiratory syncytial virus and influenza A and B viruses
Children between 6 months and 3 years of age are affected. Peak incidence occurs in 2 year old infants.
This is actually a self limiting disease and most of the children would improve within the first 24 hours of illness. Complete recovery
occurs within 4 days even without treatment.
Acute air way obstruction would need hospital admission. If the affected children have coexistent bronchopneumonia / Measles prognosis
is really poor.
X-ray chest PA view is diagnostic. Characteristic narrowing could be seen at the level of subglottis. This narrowing is seen as a Steeple / pencil tip
in the radiograph. Hence it is known as steeple's sign / pencil sign.
Xray chest showing Steeple's sign
Stridor in these patients is caused by oedema of subglottic region. This region is the narrowest portion of a child's airway.
Some children are more prone for complications than others. Children with pre-existing tracheal narrowing / chronic lung disease / BA
are at risk. In infants with recurrent croup congenital / acquired subglottic stenosis should be considered.
Westley croup score: This allows the severity of symptoms to be classified. Maximum score possible is 17. A score of 2-3 indicates mild croup,
a score of 4-7 indicate moderate croup and a score of above 8 indicates severe croup.