 Introduction/Background Inflammatory and infectious disorders of the anorectum are commonly encountered in clinical practice, but their exact incidence is unknown. They encompass a variety of anorectal disorders in a diverse population of patients who may present to the emergency department, urgent care clinic, primary care physician, or subspecialty physician such as a gastroenterologist or colorectal surgeon. Patients with inflammatory and infectious disorders of the anorectum may come in need of medical attention with acute symptoms such as pain, tenesmus, discharge, bleeding, and/or findings of sepsis. Other patients may have chronic symptoms, or their complaints may relate to a prior surgical procedure or underlying disease. Depending upon the condition and presentation, a variety of imaging modalities may be used for the initial evaluation of an anorectal complaint. Imaging may also be helpful for planning the management of rectovaginal fistulas that are the consequence of obstetric trauma from childbirth, iatrogenic anorectal or rectovaginal fistulas that are caused by radiation or surgical complications, and fistulas that result from other forms of trauma. The initial imaging in 4 anorectal disease categories is covered in this document: suspected perianal disease (perianal fistula and abscess); suspected rectal fistula (rectovescicular or rectovaginal); suspected proctitis or pouchitis; and suspected complication after proctectomy, coloproctectomy, or colectomy with pouch or other anastomosis. Special Imaging Considerations Anorectal Fistulae and Malignancy Though the focus of this topic is on inflammatory and infectious disorders of the anorectum, it is important to recognize that inflammatory disease of the anorectum may be a complication of malignancy or associated with malignancy. For example, approximately 11% of colovesical and colovaginal fistulae are caused by malignancy [1].
Anorectal Disease.  Introduction/Background Inflammatory and infectious disorders of the anorectum are commonly encountered in clinical practice, but their exact incidence is unknown. They encompass a variety of anorectal disorders in a diverse population of patients who may present to the emergency department, urgent care clinic, primary care physician, or subspecialty physician such as a gastroenterologist or colorectal surgeon. Patients with inflammatory and infectious disorders of the anorectum may come in need of medical attention with acute symptoms such as pain, tenesmus, discharge, bleeding, and/or findings of sepsis. Other patients may have chronic symptoms, or their complaints may relate to a prior surgical procedure or underlying disease. Depending upon the condition and presentation, a variety of imaging modalities may be used for the initial evaluation of an anorectal complaint. Imaging may also be helpful for planning the management of rectovaginal fistulas that are the consequence of obstetric trauma from childbirth, iatrogenic anorectal or rectovaginal fistulas that are caused by radiation or surgical complications, and fistulas that result from other forms of trauma. The initial imaging in 4 anorectal disease categories is covered in this document: suspected perianal disease (perianal fistula and abscess); suspected rectal fistula (rectovescicular or rectovaginal); suspected proctitis or pouchitis; and suspected complication after proctectomy, coloproctectomy, or colectomy with pouch or other anastomosis. Special Imaging Considerations Anorectal Fistulae and Malignancy Though the focus of this topic is on inflammatory and infectious disorders of the anorectum, it is important to recognize that inflammatory disease of the anorectum may be a complication of malignancy or associated with malignancy. For example, approximately 11% of colovesical and colovaginal fistulae are caused by malignancy [1].