3-17. ANORECTAL INFECTION
a. Definition. Anorectal infections are infections of the anus and rectum. Two
phases of anorectal infection will be dealt with here: anal abscess (the acute phase)
and anal fistula (the chronic phase).
b. Anal Abscess. An anal abscess is an acute, localized infection of an anal or
rectal gland most commonly caused by staphylococci. Signs and symptoms include a
severe throbbing pain initiated by defecation; the pain persists for many hours after
defecation. The patient feels a vague pelvic pain and may have fever. Rectal
examination may detect a tender, boggy swelling. There may be swelling of the lymph
nodes in the groin area. Treatment should be prompt without waiting for the abscess to
come to a head externally. This condition may be life threatening if the abscess drains
into the abdomen. An incision must be made and the abscess drained. Give antibiotics
only when the infection has become widespread. For a widespread infection, Sitz baths
or antibiotic therapy or a combination of both may be used.
c. Anal Fistula. In this condition, a tube-like tract opens on one end into the
anal canal and on the other end into the skin around the anus. The cause is usually
pus-producing abscesses draining spontaneously or surgically opened to drain. A
patient with a history of abscesses that go away and come again is liable to have anal
fistula. Fistulotomy, surgical incision of the fistula, is the only effective treatment.
3-18. PILONIDAL FISTULA
a. Definition. This is a fistula (an unnatural passage between two areas of the
body) near the rectum which results from a growth of subcutaneous hair. The fistula
occurs at the base of the spine in the intergluteal cleft, the area in the middle of the
body where the buttocks start. Hair frequently comes out of a pilonidal fistula which is
the origin of the name--pilonidal means a nest of hair. This problem is common in
military personnel and is frequently called "jeep disease."
b. Signs and Symptoms. Pilonidal fistulas occur in the subcutaneous layer of
the skin. Pain, tenderness, and induration (an abnormally hard spot) indicate that a
fistula has developed. There may be one or several cutaneous openings on the body's
midline. Fistulas are commonly found in the midline post anal dimple. The
inflammatory process of the fistula may subside without any treatment, or it may
progress until it ruptures or requires surgical drainage.
c. Treatment. If necessary, local anesthetic can be used and the fistula
drained. Then, pack the abscess cavity with iodoform gauze daily and irrigate with a
solution of hydrogen peroxide. Chronic cases require more extensive surgery.
Treatment is necessary because untreated cases may result in long-draining sinuses.