Post-Tussive Vomiting: Definition and Clinical Significance
Post-tussive vomiting is defined as vomiting that is directly induced by coughing episodes. 1
Definition
Post-tussive vomiting occurs when violent, repetitive coughing paroxysms trigger the vomiting reflex, leading to forceful expulsion of gastric contents. 2 This symptom is characterized by vomiting that immediately follows coughing spells rather than occurring independently. 1
Primary Clinical Association: Pertussis
The presence of post-tussive vomiting should immediately raise suspicion for pertussis infection in patients with persistent cough. 2
Diagnostic Performance in Adults
- Low sensitivity (29.8-32.5%) but high specificity (77.7-79.5%) 1
- When present in adults with acute or subacute cough, it strongly suggests pertussis and should rule in a possible diagnosis 1
- The high specificity means that when post-tussive vomiting is observed, pertussis is likely the cause 1
Diagnostic Performance in Children
- Moderate sensitivity (60.0%) and specificity (66.0%) 1
- Less helpful as a diagnostic test compared to adults, but still suggestive of pertussis 1
- Should prompt assessment for the three classical pertussis characteristics: paroxysmal cough, post-tussive vomiting, and inspiratory whooping 1
Alternative Diagnosis: Asthma
Post-tussive vomiting can also be a symptom of asthma in children, not just pertussis. 3
- In children with physician-diagnosed asthma, 56% reported a history of post-tussive emesis 3
- Children with post-tussive emesis are significantly more likely to have asthma than those without it (odds ratio 7.9) 3
- Common pitfall: Assuming all post-tussive vomiting is pertussis without considering asthma in the differential diagnosis, particularly in children with other features of reactive airway disease 4, 3
Clinical Consequences
Post-tussive vomiting leads to:
- Significant nutritional challenges and weight loss 2
- Feeding difficulties, particularly in infants 2, 5
- Need for smaller, more frequent feeds to prevent aspiration and maintain nutrition 2, 5
- Potential requirement for nasogastric or intravenous hydration if severe enough to cause dehydration 5
Management Implications
When post-tussive vomiting is identified:
- Initiate macrolide antibiotics (preferably azithromycin) immediately if pertussis is suspected to prevent transmission to contacts 2, 5
- Provide nutritional support with smaller, more frequent feeds offered immediately after coughing episodes when the patient is less likely to cough 2, 5
- Consider pertussis testing (PCR, culture, or serology) when present in a child with acute cough less than 4 weeks duration 4
- Evaluate for asthma if other features of reactive airway disease are present, especially in children 4, 3