Croup (laryngotracheobronchitis) ~ Emergency medicine.Site

Croup

Introduction:

Croup (viral laryngotracheobronchitis) is the most common cause of stridor outside the neonatal period,

commonly affecting children 6 months to 3 years old, with a peak in the second year of life.

The incidence is highest in the fall and the early winter months, and more cases occur during odd-numbered years.

'Croup is acquired through inhalation of the virus'.

The most common viruses are:

parainfluenza virus and rhinovirus,

followed by :

enterovirus and respiratory syncytial virus,
influenza virus,
human metapneumovirus, and human bocavirus
Co-infection by more than one virus is common.

Definition:

A variety of infections can cause swelling in the upper airway.

Infection can lead to laryngotracheobronchitis, or inflammation of the larynx, trachea, and bronchi.
An acute form of laryngotracheobronchitis is a common cause of croup.
A condition most often found in children between 6 months and 6 years, but can occur at any age
In northern areas, most common between October and March

a condition characterized by

stridor, hoarseness, and a barking cough that most commonly occurs in infants and small children.
Viral infection is a more common underlying cause of croup than bacterial infection.
Croup may also be caused by allergies that result in airway swelling and obstruction, or by obstruction with a foreign body.

Different between croup and epiglottis:

The poiseuille law:

holds that as the diameter of a tube decreases, resistance to flow increases exponentially.

This law explains why children—who have narrow airways—often have croup when an infection causes upper airway swelling, whereas adults with the same infection.

Clinical features:

The clinical course of croup varies, but symptoms typically begin after 1

to 3 days of nasal congestion, rhinorrhea, cough, and low-grade fever.

Classic symptoms are

harsh barking cough,

hoarse voice, and

stridor.

Symptoms may be worse at night.

The severity of symptoms is related to the amount of edema and inflammation of the airway.

Assess for tachypnea, stridor at rest, nasal flaring, retractions, lethargy or agitation, and oxygen desaturation.

The “typical” duration of symptoms ranges from 3 to 7 days.

Symptoms are most severe on the third and fourth days of illness and then improve.

Diagnosis:

Diagnosis is clinical. Laboratory studies, viral tests, or radiographs are needed only in children who fail to respond to conventional therapy or if considering another diagnosis such as epiglottitis, retropharyngeal abscess, or aspirated foreign body.

If radiographs are ordered, provide physician monitoring during the procedure, because agitation may worsen existing airway obstruction.