Pneumomediastinum following transanal excision of a rectal tumour

A 45 year old male underwent full thickness transanal excision of a recurrent rectal villous adenoma. On the evening of surgery he developed an unexplained fever of 38.9 degrees C. Plain X-rays revealed a significant pneumomediastinum and pneumoretroperitoneum. This was thought to be due to passage of intrarectal air into the mesorectum and extravasation along tissue planes. The patient was managed with restricted fluids by mouth, an antidiarrhoeal agent, intravenous antibiotics, and frequent clinical and radiological observations. During the following 48 hours the fever settled and the pneumomediastinum resolved by the tenth postoperative day. Sigmoidoscopic examination at this time showed a healing rectal wound. This case illustrates a potential consequence of pelvic surgery and emphasizes the extent of the visceral space that exists as a continuum between the pelvis, abdomen, thorax and neck. This is an unusual complication with a dramatic radiological appearance, but one that can be managed successfully with expectation of a completely benign course.