Pneumoperitoneum: Not Always due to an Intestinal Perforation!!

Sir,

Pneumoperitoneum or presence of free air in the abdominal cavity is most commonly due to perforation of a hollow viscus. An abdominal radiograph showing pneumoperitoneum along with clinical signs of peritonitis necessitates emergency abdominal exploration. We came across a case where a child presented with peritonitis and free abdominal air but on exploration was found to have empyema secondarily causing pneumoperitoneum.

A 4-year-old male child presented to the emergency with severe right upper quadrant abdominal pain, distension, and vomiting for 2 days. He also had a history of high-grade fever and cough for the past 20 days. On examination, the child was febrile and had tachycardia and severe tenderness and guarding in the right side of the abdomen. An erect abdominal X-ray revealed pneumoperitoneum with severe right-sided pneumonitis [Figure 1]. On laparoscopic exploration, there was a large loculated suprahepatic pus collection, but rest of the abdominal viscera including the liver was normal [Figure 1]. Further exploration after clearing the pus revealed a right-sided diaphragmatic rent with irregular margins measuring approximately 1 cm diameter through which pus was passing from the right thoracic cavity into the abdomen. The diaphragmatic defect was small, central and had jagged edges, thus ruling out congenital diaphragmatic hernia. Thus, the diagnosis of right-sided empyema secondarily causing diaphragmatic rupture and pyopneumoperitoneum was confirmed. Thorough lavage of the pyoperitoneum and right-sided intercostal drain (ICD) insertion was done. The child recovered with high-grade antibiotics and chest physiotherapy. ICD was removed after 4 days once the output stopped and pneumonitis resolved. A check postoperative ultrasound was also done to rule out liver abscess, which was normal.

Figure 1.

X-ray showing pneumoperitoneum and laparoscopic image showing normal liver (white arrow) with diaphragmatic rent (black arrow) and pus trickling from right thoracic cavity into the abdomen

Less than 5% cases of pneumoperitoneum in children are due to causes other than hollow viscus perforation.[1] The most common nonsurgical causes of pneumoperitoneum in children are cardiopulmonary resuscitation, mechanical ventilation, gynecologic manipulation, peritoneal dialysis, and gastrointestinal endoscopic procedures.[2,3] These cases can be suspected preoperatively due to predisposing conditions such as mechanical ventilation and absence of peritonitis. Our patient had peritonitis, systemic signs, and no predispositions, thus obviating any suspicion of nonsurgical pneumoperitoneum. Nevertheless, this case highlights that in a patient with clinical and radiological evidence of peritonitis but with negative laparotomy findings, thorough search for alternative pathologies, which may not necessarily be abdominal, needs to be undertaken.

Although empyema can cause complications such as loculation, lung collapse, and cutaneous fistulas, empyema causing diaphragmatic rupture and secondary abdominal peritonitis is not known. Such cases provide interesting exceptions to established surgical beliefs.

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