Synonyms: Acute laryngotracheal bronchitis, Viral laryngotracheal bronchitis
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.
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.
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In patients with mild croup it is sufficient if supportive therapy is given. The child should not be sedated as this will reduce the respiratory drive. In moderately severe cases, the patient can be nebulized with epinephrine (1 ml of i in 1000 epinephrine which is diluted with 3 ml of 0.9% saline). Epinephrine is known to cause reduction of mucosal oedema. Corticosteroids should be administered in patients with severe croup. Oral dexamethazone is administered in doses of 0.6mg/kg. Budesonide 2mg may be used as nebulization. Oxygenation can be provided with face mask in moderate croup cases. In patients with severe degree of croup with altered sensorium intubation may have to be resorted to to ventilate the patient.