Why Children Vomit with Upper Respiratory Infections (URIs)
Children commonly vomit during upper respiratory infections due to postnasal drip stimulating the gag reflex and activation of inflammatory pathways during viral infections.
Mechanisms of Vomiting in Pediatric URIs
Postnasal Drip Mechanism
- Viral URIs cause inflammation of the nasal mucosa, leading to increased mucus production 1
- This mucus drains down the back of the throat (postnasal drip), which can:
- Stimulate the gag reflex, especially in young children with more sensitive gag reflexes
- Trigger the vomiting center in the brain when excessive mucus is swallowed
Inflammatory Response
- Viral infections activate inflammatory pathways and the parasympathetic nervous system, generating various symptoms including nausea and vomiting 1
- The inflammatory response can cause irritation of the gastric mucosa, contributing to gastrointestinal symptoms
Clinical Association with Pertussis
- Posttussive vomiting is a key diagnostic feature of pertussis (whooping cough) with high specificity (77.7%) in adults and moderate sensitivity (60%) in children 1
- In children with acute cough, posttussive vomiting suggests possible pertussis infection 1
Age-Related Factors
- Young children are more prone to vomiting with URIs due to:
- Immature gag reflex control
- Higher mucus production relative to their smaller airway size
- Less developed ability to clear secretions effectively
- More frequent swallowing of mucus rather than expectorating
Clinical Considerations
Distinguishing URI Symptoms
- Children with URIs typically present with sneezing, rhinorrhea, nasal congestion, hyposmia/anosmia, facial pressure, postnasal drip, sore throat, cough, ear fullness, fever, and myalgia 1
- Vomiting is more common in children with significant postnasal drip or paroxysmal cough
Diagnostic Implications
- Vomiting alone should not be used to distinguish viral from bacterial infections 1
- However, posttussive vomiting combined with paroxysmal cough and absence of fever may suggest pertussis rather than a simple viral URI 1
Common Pitfalls in Assessment
- Misdiagnosis pitfall: Assuming vomiting indicates a gastrointestinal infection rather than a URI
- Treatment pitfall: Unnecessarily prescribing antibiotics for what is typically a viral infection
- Assessment pitfall: Failing to recognize that posttussive vomiting may be a clue to pertussis in unvaccinated children or those with waning immunity
Management Implications
Supportive care is the mainstay of treatment for viral URIs with vomiting 2:
- Maintain adequate hydration
- Use saline nasal drops/spray to thin secretions
- Consider honey for cough in children over 1 year of age
- Administer acetaminophen/ibuprofen for fever and discomfort as needed
Position the child upright or semi-reclined after feeding to minimize postnasal drip-induced vomiting
Consider medical evaluation if:
- Vomiting is severe or leads to dehydration
- Symptoms persist beyond 10 days without improvement
- Fever ≥39°C with purulent nasal discharge for at least 3 days (may suggest bacterial sinusitis) 2
Remember that most URIs in children are viral in nature and will resolve with supportive care. Vomiting in this context is typically a self-limiting symptom that improves as the URI resolves.