Idiopathic pneumoperitoneum, a possible complication of pure oxygen administration in a neonate with laryngomalacia: a case report.

INTRODUCTION AND CLINICAL IMPORTANCE: Idiopathic pneumoperitoneum can occur in a full-term neonate due to the administration of pure oxygen. Recognition of this rare mechanism is necessary to avoid unnecessary surgical exploration. CASE PRESENTATION: We report the case of a six-day-old male neonate with a history of respiratory distress and non-invasive pure oxygen support (FiO2 = 1.00) via a nasal cannula. He progressively developed abdominal distension, but had no fever, abdominal tenderness, or redness. A massive pneumoperitoneum was noted on a plain X-ray. While preparing for surgical exploration, the distension regressed, and idiopathic pneumoperitoneum was diagnosed and managed conservatively. The respiratory distress was caused by laryngomalacia, which was also managed conservatively, with no complications noted 6 months after admission. CLINICAL DISCUSSION: Idiopathic pneumoperitoneum should be suspected in neonates with a history of respiratory distress but without classic clinical signs of peritonitis. Notably, noninvasive administration of pure oxygen alone can cause idiopathic pneumoperitoneum. CONCLUSION: In a full-term neonate, non-invasive administration of pure oxygen for laryngomalacia can cause idiopathic pneumoperitoneum, which may have a favorable outcome with conservative management.