Strangulated inguinal hernia complicating colonoscopy

Abstract

Colonoscopy is widely used as a primary investigation of terminal ileal and colorectal disease. Colonoscopy may be more difficult and dangerous in the presence of large inguinal hernias, as loops of bowel and the colonoscope may become incarcerated in the hernia.1, 2 Acute presentation of a strangulated inguinal hernia has not previously been reported as a complication of colonoscopy. A 64-year-old man attended for a colonoscopy as follow-up of previous adenomatous polyps. Colonoscopy was performed uneventfully by an experienced operator. Sedation was with 5 mg midazolam and 50 mg pethidine; air was used for insufflation. The terminal ileum was intubated and a 10 mm pedunculated tubulovillous adenoma was removed from the transverse colon by snare excision. Routine post-procedure care was uncomplicated. Six hours later the patient consulted his general practitioner because of sudden onset central abdominal pain and vomiting. He was referred back to hospital with a provisional diagnosis of colonic perforation. Examination showed a tender mass in the right inguinal region; radiography did not demonstrate any free subdiaphragmatic air. At surgery the diagnosis of a small right indirect inguinal hernia containing a segment of strangulated ileum was confirmed. The ischaemic segment was resected and repair of the hernial defect completed. Recovery was unremarkable. Colonoscopy is a generally safe procedure, with significant complications occurring in 0.3% of cases overall, although haemorrhage can complicate polypectomy in 1% of cases.3 Loops of sigmoid colon within a large left inguinal hernia may pose problems at colonoscopy. It may be difficult to traverse the segment, and the extraction of the endoscope may be problematical.4 This is the first report of strangulation in a previously unrecognised hernia arising as a result of colonoscopy. The temporal relationship between colonoscopy and presentation suggests that the increase in intra-abdominal pressure from insufflation of the bowel exacerbated any predisposing weakness in the abdominal wall and facilitated herniation of the small bowel mucosa. Although such acute complication of a previously unrecognised hernia may be rare, it is important that the possibility is considered. Health-care professionals and patients are aware of perforation as a complication of colonoscopy, but other causes of acute abdominal pain after colonoscopy should be included in the differential diagnosis.