ANORECTAL ABSCESSES Aetiology

ANORECTAL ABSCESSES Aetiology

Acute sepsis in the region of the anus is common, more in men than women, although perianal infections with skin-type organisms (and thus unrelated to fistula) are evenly distributed. The cryptoglandular theory of intersphincteric anal gland infection (Parks) holds that pus, which travels along the path of least resistance, may spread caudally to present as a peri anal abscess, laterally across the external sphincter to form an ischiorectal abscess or, rarely , superiorly above the anorectal junction to form a supralevator intermuscular or pararectal abscess (depending on its relation to the longitudinal muscle) ( Figure 80.27 ), as well as circumferentially in any of the three planes: intersphincteric/intermuscular, ischiorectal or pararec tal supralevator ( Figure 80.28 ). Sepsis unrelated to anal gland infection may occur at other sites, including submucosal abscess (following haemorrhoidal sclerotherapy , which usually resolves spontaneously), mucocutaneous or marginal abscess (infected haematoma), isc hiorectal abscess (foreign body , trauma, deep skin-related infection) and pelvirectal supralevator sepsis orig inating from pelvic disease. Underlying rectal disease, such as neoplasm and particularly Crohn’s disease, may be the cause. Immunosuppressed patients or those with diabetes or acquired immunodeficiency syndrome (AIDS) may present with peri anal or pelvirectal se psis that may run an aggressive course.