Perianal Fistula, complete vs. Perianal Fistula, incomplete
Left picture: The infant has a complete type of a subcutaneous fistula which starts from an anal crypt. Right picture: Here, probably a congenital, incomplete subcutaneous fistula is present. Due to an abscess with ulceration in the anal channel at 6 to 9 o´clock, the fistula became symptomatic, which is visible in the second figure from top to bottom on the corresponding side. A secondary breaking through in direction of the outside of the anus occurred only underneath the skin, which is recognizable in the third picture on the corresponding side. In the fourth figure on the corresponding side the different types of anal fistula are visible (M. Bettex): Except for cases with Crohn´s disease (3= ischiorectal variant of the anorectal type), mainly complete and incomplete subcutaneous forms are observed in children (= 1a-c) as well as transsphinteric forms (= 2a/b). Leading symptoms may be blood on the stool; however, a moistening anus and inflammtory perianal and anal findings are in the forefront of the clinical presentation.
Left picture: Anal findings in a 6-month-old infant with a perianal reddening; an opening is visible at 11 o´clock. It displays some secretion, can be cannulated by a probe, the end of which becomes visible in the anal channel. Right picture: Moistening anus in a male newborn. The perianal region is humid, and at 3 o´clock at the anocutaneous line some granulation tissue seems to be visible. In addition there is a perianal swelling at 7 to 8 o´clock.