RESUMEN
BACKGROUND: Spontaneous pneumomediastinum (SPM) is a rare and often unrecognized condition of which vomiting is one of the reported triggering factors. Differentiating SPM from Boerhaave's syndrome (pneumomediastinum secondary to esophageal breach) is the first step in management and prognosis. OBSERVATION: A 27-year-old woman with systemic lupus erythematous presented to the emergency department with epigastralgia, incoercible vomiting and diarrhoea. Abdominal CT showed circumferential thickening of the duodenum and bilateral ureteritis. Chest sections showed pneumomediastinum extending to the cervical region. Therapeutic management was based on prophylactic antibiotic therapy and an absolute diet (fasting). A CT scan with upper gastrointestinal opacification was performed to prevent esophageal rupture and showed quasi-obstructive thickening of the antral mucosa. The diagnosis was lupus enteritis and pneumomediastinum was secondary to the vomiting efforts. The patient was placed on corticosteroids and a favorable outcome ensued. CONCLUSION: Strenuous vomiting is one of the precipitating factors of SPM. Boerhaave's syndrome is the main differential diagnosis with a poor prognosis, unlike SPM, which has a good prognosis with conservative treatment.