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Croup

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.  

Investigations:

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.


 Score 0 1 2 3 4 5
 Inspiratory Stridor - Audible
with stethoscope
 Audible without 
stethoscope
   
 Retraction - Mild Moderate Severe  
 Air entry Normal Decreased Severely
decreased
   
 Cyanosis None    With agitation At rest
 Conscious level Normal     Altered


Treatment:

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.  





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