Rectal trauma occurs due to various injuries, like anorectal avulsion, automobile, gunshot or stab wounds, foreign body ingestion, drug trafficking, or erotic activity. Diagnosis may be difficult, especially in patients who cannot or will not offer a detailed description of their injury.
Patients may present with isolated rectal trauma or associated injuries like pelvic fractures or penetrating abdominal, buttock or thigh injuries that are potentially life threatening. If severe, these lesions have a 50% mortality rate. Bone fragments may induce rectal wall laceration. While inquiring about the history of the disease, the physician must obtain information about any pain, tenesmus, incontinence and associated genitourinary and abdominal symptoms . In military injuries, type, trajectory, and velocity of the penetrating foreign body must be known in order to understand potential lesions .
In selected cases, careful clinical examination (inspection, sphincter tonus assessment) followed by digital evaluation should be performed, although controversy exists regarding the utility of the latter method  . However, it can detect gross rectal blood loss and laceration  . In sexual assault, the physician should keep in mind that disruption of the rectal wall is likely and document evidence if the patient is stable. Prostate evaluation in men is useful if concomitant lesions of the urethra are suspected. Examination should also assess vital signs according to the Advanced Trauma Life Support protocol defined by the American College of Surgeons. Peritonitis and pelvic fracture signs should be looked for. If a perineal penetration wound is noticed, entry and exit signs should be documented. Women should also undergo vaginal bimanual and speculum examination with focus on the posterior wall.
Clinical evaluation should be followed by blood workup and imaging studies. The complete blood cell count may show acute posthemorrhagic anemia. Rigid or flexible proctoscopy or sigmoidoscopy offer valuable information  in penetrating and blunt injuries  , but they should be performed carefully and gently by an experienced doctor in order to prevent further injury. Despite the fact that they are the gold standard in detecting rectal damage , if other imaging methods offer reliable information, they can be excluded from the workup. However, sigmoidoscopy can sometimes fail to identify wounds and may have up to 31% false negative results .
Computer tomography can be used in rectal trauma, but if associated bowel injury is suspected, evaluation can prove difficult  and oral, intravenous or rectal contrast should be used, if appropriate, in order to increase sensitivity and specificity . Bladder lesions can also be evaluated by this method. Triple-contrast helical computed tomography has higher accuracy if combined with contrast enema  . This latter method can also be applied by itself.
Guaiac testing is another complementary diagnosis method. It has acceptable sensitivity (69%), but low specificity (33%) .