-IBIS-1.5.0-
tx
digestive system
anal fistula
diagnoses

definition and etiology

definition:
aka "fistula in ano"; an abnormal passage from the rectum to the outside originating above the internal sphincter; usually from spontaneous or surgical drainage of a pyogenic abscess or occasionally granulomatous disease of the intestine (regional enteritis or TB). Most originate in the anorectal crypts; others may result from diverticulitis, neoplasm, and trauma. In infants, these are congenital and are more common in boys. Rectovaginal fistulae may be congenital or may follow radiation therapy, pelvic surgery, childbirth, or malignancy.

signs and symptoms

signs and symptoms:
• history of recurrent abscess followed by discharge
• one or more secondary openings visible
• in granulomatous disease, the discharge may be watery and the margins of the opening reddened
• cordlike tract may be palpated

lab findings:
• anoscopy or sigmoidoscopy is often required

course and prognosis

If the fistula is secondary to pregnancy or trauma, the prognosis is good with surgical intervention. The wound heals via granulation with generally good results. If secondary to degeneration of the surrounding tissues, the health of the connective tissue must be addressed before the fistula can satisfactorily resolve.

differential diagnosis

• hidradenitis suppurativa
• pilonidal sinus
• dermal suppurative sinuses
• urethroperineal fistulae must be differentiated from cryptogenic fistulae


footnotes