Denouement and Discussion
Pneumoperitoneum Demonstrated by Transillumination
Manifestations
Until recently, abdominal roentgenography was the only diagnostic method for detecting the presence of a pneumoperitoneum in the neonate. Transillumination, which has been used successfully to detect free air in the chest, can also detect the presence of free air within the peritoneal cavity. If a pneumoperitoneum is present, the entire peritoneal space glows brightly and the abdominal wall vessels and falciform ligaments can be visualized. The liver and spleen can also be faintly seen if a large pneumoperitoneum is present.Bowel gas also transilluminates in the small neonate, but the falciform ligament and abdominal wall vessels cannot be identified.Abnormal transillumination of the peritoneal space and visualization of the abdominal wall vessels, falciform ligament, liver, and spleen also occurs with ascites, but the transillumination is not as bright. Ascites and pneumoperitoneum can be differentiated by placing the neonate in the decubitus