Table 3 Presenting symptoms, imaging and clinical considerations in relation to site and causes of large bowel perforation

Colorectal

Abdominal pain, nausea, anorexia, vomiting, fever, sepsis

IP gas (cecum, transverse, sigmoid, upper 2/3 of rectum), EP gas (ascending, descending colon, lower 1/3 rectum), extraluminal faecal contents, oral/rectal contrast leakage, wall defect, faecal material protruding through wall/lying within abdominal cavity, bowel wall thickening (> 5 mm), fat stranding, abnormal wall enhancement, abscess, inflammatory mass adjacent to colon, free fluid

Tumour

Wall thickness > 1.39 cm, irregular wall configuration, lymphadenopathy, metastatic disease, free gas, minimal in tumour necrosis, free gas massive following obstruction

Tumour necrosis/following obstruction

Iatrogenic

Disproportionate amount of extraluminal gas, stent extending through wall defect

History of instrumentation, opioids, radiation therapy, NSAIDs, chemotherapeutic regimens, corticosteroids

Spontaneous

Caecal diameter > 14 cm, diffuse bowel dilatation without transition point

Severely ill, postoperative patients

Diverticulae

Inflamed diverticulum, pneumoretroperitoneum

Trauma

Foreign body

Foreign body, colovesical fistula, inflammatory mass

Stercoral

Faecal impaction with wall thickening,

Faecaloma protruding through colonic wall/in abdominal cavity

Elderly, chronic costipation, scleroderma, bedridden patients

Infectious

Salmonella, yersinia, tuberculosis, amoebiasis, Cl. difficile, E. coli, schistosomiasis, shigellosis, herpes, gonorrhoea, syphilis, LGV, CMV

Ischemia

Poor/absent mural enhancement, pneumatosis intestinalis, vascular occlusion, portomesenteric gas

Low-flow states, vascular occlusion

IBD

Skip lesions, intramural fat, fistula formation, marked colonic dilatation in UC

Free perforation rare