What does it mean when you cough until you vomit?

Coughing Until Vomiting: Clinical Significance and Evaluation

When you cough until you vomit (posttussive vomiting), this is a highly specific clinical sign that strongly suggests pertussis (whooping cough) infection, though it can occasionally occur with other severe coughing illnesses. 1, 2

What This Symptom Indicates

Posttussive vomiting occurs because violent, repetitive coughing paroxysms trigger the vomiting reflex, forcefully expelling gastric contents. 3 This symptom has important diagnostic implications:

• In adults with acute or subacute cough, posttussive vomiting has high specificity (77.7%) for pertussis, meaning when present, it strongly suggests this disease, though sensitivity is low 1, 2
• In children, posttussive vomiting has moderate sensitivity (60.0%) and specificity (66.0%) for pertussis 1, 2
• The presence of this symptom should immediately raise suspicion for pertussis infection in anyone with persistent cough 3

When to Suspect Pertussis

You should strongly consider pertussis when cough lasting >2 weeks is accompanied by any of these features: 1, 2

• Paroxysmal cough (recurrent prolonged coughing episodes with inability to breathe during spells) 1
• Posttussive vomiting (vomiting induced by coughing) 1
• Inspiratory whooping (continuous inspiratory airway sound with whooping quality) 1
• Absence of fever 1, 2

A critical pitfall: Do not dismiss pertussis in vaccinated adolescents and adults, as the illness can be milder with absent whoop in previously vaccinated individuals. 2

Other Potential Causes

While pertussis is the most specific diagnosis, severe coughing with vomiting can occasionally occur with: 1, 4

• Severe acute bronchitis from viral upper respiratory tract infections 1, 4
• Gastroesophageal reflux disease (GERD), though vomiting here is typically related to reflux itself rather than purely post-tussive 5, 6
• Severe asthma exacerbations with intense coughing paroxysms 1

Immediate Clinical Actions Required

When posttussive vomiting is identified, you should: 2, 3

1. Initiate macrolide antibiotics (preferably azithromycin) immediately to prevent transmission to contacts, even before laboratory confirmation 2, 3
2. Order nasopharyngeal PCR testing for definitive diagnosis, as this is the preferred confirmatory test 2
3. Assess for the complete clinical picture: paroxysmal cough pattern, inspiratory whoop, absence of fever 1, 2
4. Provide nutritional support with smaller, more frequent feeds to prevent aspiration and maintain nutrition, as this symptom leads to significant weight loss and feeding difficulties 3

Red Flags Requiring Urgent Evaluation

Seek immediate medical attention if coughing with vomiting is accompanied by: 1

• Hemoptysis (coughing blood) 1
• Prominent dyspnea, especially at rest or at night 1
• Systemic symptoms including fever, weight loss 1
• Abnormal respiratory examination findings 1
• In infants under 12 months: apneic spells, cyanosis, or minimal cough with vomiting, as these require immediate hospitalization 7

Special Considerations for Infants

Infants under 12 months with suspected pertussis and posttussive vomiting require hospitalization for continuous cardiorespiratory monitoring due to high risk of life-threatening complications including apnea, bradycardia, and death. 7 They need frequent small feedings immediately after coughing episodes when less likely to cough, with nasogastric or IV hydration if vomiting causes significant dehydration or weight loss. 7

Clinical Context Matters

The physical examination between coughing episodes is often surprisingly unremarkable in pertussis, with diagnosis primarily relying on observing or eliciting the characteristic paroxysmal cough pattern rather than specific physical signs. 2 Normal lung auscultation between paroxysms is common, as pertussis primarily affects airways rather than causing parenchymal disease. 2

Patients are most infectious during the early catarrhal stage and first 3 weeks after cough onset, when symptoms are least specific, making early recognition and treatment critical for preventing transmission. 2