Proctitis refers to inflammation of the rectum. This has various causes to include infectious, radiation treatment, inflammatory bowel disease, fecal impaction and ischemic causes. Proctitis on CT will present with a thickened rectal wall and possible inflammatory changes in the surrounding fat.
Patients will present with discharge, bleeding, painful defecation and a feeling that you need to pass stools even though your bowel is empty (tenesmus). Infectious causes can be caused by various pathogens to include syphilis and gonorrhea to name a few. Inflammatory bowel disease like ulcerative colitis can also cause this appearance.The CT appearance will be non specific for this but the clinical history will help with the diagnosis.
Radiation treatment proctitis is often done for cancers of the pelvis. Proctitis related to radiation will have thickening of the rectal wall. There will often be edema in the treated and surrounding tissues. Most importantly, there will be a history of radiation treatment for cancer.
Ischemic proctitis or one which is caused by lack of blood flow is rare. This is because the rectum has abundant blood supply from several vessels. It usually results from severe vascular disease, vessel occlusion or poor blood flow. The appearance on CT is non specific with thickened rectal wall. The diagnosis is made with colonoscopy and biopsy.
Fecal impaction proctitis or stercoral proctitis is an inflamed rectum from retained stool. Chronic constipation can lead to fecaloma formation which is hard dehydrated stool in the rectum. This usually occurs in the elderly, bed bound and demented patients. The pressure from the stool can lead to reduced blood flow and eventual tissue death (necrosis). This can be followed by perforation which can be deadly. CT will show a dilated stool filled rectum with inflammatory changes.
Proctitis or inflamed rectum has many causes. The imaging appearance is often non specific or does not provide a specific reason. The clinical history is important with this imaging finding. Sometimes a colonoscopy and biopsy will be needed for definitive diagnosis. CT will show any potential complications like perforation which will require urgent treatment.