History
Croup usually begins with nonspecific respiratory symptoms (ie, rhinorrhea, sore throat, cough). Fever is generally low grade (38-39°C) but can exceed 40°C. Within 1-2 days, the characteristic signs of hoarseness, barking cough, and inspiratory stridor develop, often suddenly, along with a variable degree of respiratory distress. Symptoms are perceived as worsening at night, with most emergency room visits occurring between the hours of 10 pm and 4 am. Symptoms typically resolve within 3-7 days, but can last as long as 2 weeks.
Spasmodic croup (recurrent croup) typically presents at night with the sudden onset of "croupy" cough and stridor. The child may have had mild upper respiratory complaints prior to this, but more often has behaved and appeared well prior to the onset of symptoms. Allergic factors may cause recurrent croup due to respiratory epithelial changes from the viral infection.
Another diagnostic consideration for patients with recurrent croup symptoms is gastroesophageal reflux (GER). Studies of children presenting with recurrent croup have reported relief of their respiratory symptoms when treated for reflux. [13]
Physical Examination
The clinical presentation of croup has wide variation. Most children have just a "croupy" cough and hoarse cry. Some may have stridor only upon activity or agitation, whereas others may have audible stridor at rest and clinical evidence of respiratory distress. Overall however, a child with croup typically does not appear toxic. Paradoxically, a child with a severe case of croup may have "quiet" stridor due to a significant degree of airway obstruction.
Given the wide clinical spectrum of croup, the patient's symptoms can range from minimal inspiratory stridor to severe respiratory failure. [14] In mild cases, respiratory sounds at rest are normal; however, mild expiratory wheezing may be heard. Children with more severe cases have inspiratory and expiratory stridor at rest with visible suprasternal, intercostal, and subcostal retractions. Air entry may be poor. Lethargy and agitation occur and are due to marked respiratory difficulty and, hence, causing hypoxemia and increasing hypercarbia. Respiratory arrest may occur suddenly during an episode of severe coughing. Additional warning signs of severe respiratory disease include tachypnea, tachycardia (out of proportion to fever), and hypotonia. Children unable to maintain adequate oral intake will become dehydrated. Cyanosis is a late, ominous sign.
Scoring systems
Croup scores have been developed to assist the clinician in assessing the patient's degree of respiratory compromise. A commonly cited croup severity rating score is called the Westley score. Although widely used for research purposes and for the evaluation of treatment protocols, its clinical application has not been extensively studied. The Westley score evaluates the severity of croup by assessing five factors: level of consciousness, cyanosis, stridor, air entry, and retractions. The point values given for each factor are listed below, and the final score sum has a range of 0 to 17.
-
Level of consciousness: Normal, including sleep - 0 points, Depressed - 5 points
-
Cyanosis: None - 0 points, Upon agitation - 4 points, At rest - 5 points
-
Inspiratory stridor: None - 0 points, Upon agitation - 1 point, At rest - 2 points
-
Air entry: Normal - 0 points, Mild decrease - 1 point, Marked decrease - 2 points
-
Retractions: None - 0 points, Mild - 1 point, Moderate - 2 points, Severe - 3 points
With the Westley rating system, a sum score of less than 2 indicates mild disease. Mild disease is defined as an occasional barking cough, hoarseness, no stridor at rest, and mild or absent suprasternal or subcostal retractions. The majority (about 85%) of children who present to the emergency department have mild croup. A sum score of 3-5 indicates moderate disease. Moderate disease findings include frequent cough, audible stridor at rest, and visible retractions, but little distress or agitation. Severe disease is indicated with a sum score range of 6-11. Patients present with prominent inspiratory (and, occasionally, expiratory) stridor, frequent cough, marked chest wall retractions, decreased air entry on auscultation, significant distress and agitation. Fortunately, severe croup is rare. A sum Westley score of ≥ 12 indicates impending respiratory failure. At this point, a barking cough and stridor may no longer be prominent. Lethargy, cyanosis, and decreasing retractions are harbingers of impending respiratory failure.
Another clinically useful croup severity assessment rating system has been developed by the Alberta Clinical Practice Guideline Working Group. [15, 16] By following this classification scheme, 21 different general emergency rooms in Alberta, Canada diagnosed 85% of children to have mild croup, and less than 1% with severe croup. The assessment tool used was as follows:
-
Mild severity - Occasional barking cough, no audible stridor at rest, and either no or mild suprasternal and/or intercostal retractions
-
Moderate severity - Frequent barking cough, easily audible stridor at rest, and suprasternal and sternal wall retractions at rest, with no or minimal agitation
-
Severe severity - Frequent barking cough, prominent inspiratory (and occasionally expiratory) stridor, marked sternal wall retractions, significant agitation and distress
-
Impending respiratory failure - Barking cough (often not prominent), audible stridor at rest, sternal wall retractions may not be marked, lethargy or decreased consciousness, and often dusky appearance without supplemental oxygen support
In addition, as a component of both Westley and Alberta clinical practice guidelines, recommendations for medical interventions and care are presented in an algorithm based on the severity of the patient’s initial symptoms and corresponding assessment.
-
Child with croup. Note the steeple or pencil sign of the proximal trachea evident on this anteroposterior film. Courtesy of Dr. Kelly Marshall, CHOA at Scottish Rite.
-
Steeple sign on radiograph.
