What are the risk factors for severe croup in children?

From the Guidelines

The main risk factors for severe croup in children include young age, pre-existing medical conditions, and environmental factors, with the highest risk in infants 6 months to 3 years of age. Children with a history of previous severe croup episodes are at increased risk for subsequent severe episodes. Anatomical abnormalities of the airway, such as subglottic stenosis or laryngomalacia, significantly increase the risk of severe symptoms. Pre-existing medical conditions like asthma, respiratory infections, or immunodeficiency can worsen croup manifestations. Environmental factors also play a role, with exposure to cigarette smoke and allergens potentially exacerbating symptoms. The timing of symptom onset is important, as croup that worsens at night or progresses rapidly suggests a more severe course. Children presenting with stridor at rest, significant respiratory distress, decreased oxygen saturation, altered mental status, or dehydration require immediate medical attention as these are signs of severe disease. These risk factors are significant because croup involves inflammation and narrowing of the subglottic airway, and children naturally have smaller airways than adults, making them more susceptible to significant airway compromise when inflammation occurs.

Some key points to consider when assessing the risk of severe croup in children include:

• Young age, with the highest risk in infants 6 months to 3 years of age 1
• Pre-existing medical conditions, such as asthma, respiratory infections, or immunodeficiency 1
• Anatomical abnormalities of the airway, such as subglottic stenosis or laryngomalacia 1
• Environmental factors, such as exposure to cigarette smoke and allergens 1
• Timing of symptom onset, with croup that worsens at night or progresses rapidly suggesting a more severe course 1
• Presence of stridor at rest, significant respiratory distress, decreased oxygen saturation, altered mental status, or dehydration, which require immediate medical attention 1

It's worth noting that the evidence for these risk factors is based on studies of community-acquired pneumonia and bronchiolitis, which may not be directly applicable to croup. However, the principles of assessing disease severity and identifying high-risk patients are relevant to all respiratory illnesses in children. As stated in the guidelines for the management of community-acquired pneumonia in childhood, indicators for admission to hospital in infants include oxygen saturation <92%, cyanosis, respiratory rate >70 beats/min, difficulty in breathing, intermittent apnoea, grunting, not feeding, and family not able to provide appropriate observation or supervision 1.

From the Research

Risk Factors for Severe Croup

The risk factors for severe croup in children are not explicitly stated in the provided studies. However, the following factors can be associated with a higher risk of developing moderate to severe croup:

• Age: Croup affects about 2% to 3% of preschool-aged children every year, usually between the ages of 6 months and 3 years 2, 3, 4.
• Viral infection: Croup is thought to be triggered by a viral infection, with Parainfluenza virus and RSV being the most common pathogens 5, 3, 6.
• Upper airway obstruction: Croup leads to signs of upper airway obstruction, which can be severe in some cases 3, 4.

Management and Treatment

The management and treatment of croup can help reduce the risk of severe croup:

• Corticosteroids: The use of steroids, such as dexamethasone, can improve symptoms and reduce the need for hospitalization in children with croup of any severity 2, 4, 6.
• Nebulized epinephrine: The addition of nebulized epinephrine can improve symptoms and reduce length of hospitalization in patients with moderate to severe croup 4, 6.
• Heliox: There is some evidence to suggest a short-term benefit of heliox inhalation in children with moderate to severe croup who have been administered oral or intramuscular dexamethasone 5.

Key Points

Some key points to note about croup include:

• Croup is a common respiratory illness affecting children, especially those under the age of 6 years.
• Viral infections are the primary cause of croup.
• Corticosteroids and nebulized epinephrine are effective treatments for croup.
• Heliox may have a short-term benefit in some cases of moderate to severe croup.
• Hospitalization may be necessary for children with severe croup or those who do not respond to treatment 5, 2, 3, 4, 6.