In the early stages of radiation enteritis or in cases of mild injury, there may be no specific findings on finger examination. There may be only anal sphincter contracture and tenderness. In some cases, the anterior rectal wall may be edematous, thickened, hardened, and blood-stained on the fingers. Sometimes ulcers, strictures, or fistulas can be palpated, and in 3% of cases with severe rectal damage, a rectovaginal fistula is formed. A vaginal examination can be done at the same time to help with the diagnosis.
Colonoscopy is an essential tool for diagnosing radiation proctitis, assessing the extent of the lesion based on typical microscopic changes, and performing tissue biopsy if necessary to rule out tumor recurrence. The colonoscopic changes of CRP include capillary dilation, mucosal congestion, ulceration, stenosis, necrosis, etc., among which capillary dilation is the most typical.
Laboratory tests include routine blood and fecal occult blood tests to understand the degree of anemia; tumor marker tests to exclude recurrence; breath test, intestinal content culture, blood bile salt product test, etc. can help to clarify the cause of diarrhea.
Imaging examinations: pelvic floor ultrasound and rectal endoluminal ultrasound can help to determine the cause of anal pain and anal incontinence; CT/MRI of abdomen and pelvis can help to exclude tumor recurrence; Gastrointestinal tract imaging can help to determine the location and degree of radioactive intestinal fistula.