Peri-anal and Peri-rectal Abscess

The ischio-rectal fossa is peculiarly liable to attacks of inflammation resulting in abscess, as it is filled with much loose connective tissue which supports a considerable amount of fat, and is situated in a region which is constantly exposed to injury both from within and without. It is a very vascular part, being freely supplied by branches of the inferior hemorrhoidal arteries and veins; the latter, being large and destitute of valves, empty into the portal circulation. Abscess in this region is of very common occurrence, and may attack any one at any period of life. It occurs more frequently among men than among women, and usually during middle life.

Abscesses in this situation may be acute or chronic. The former variety may be caused by injury to the anus or to the surrounding parts; by exposure to cold and wet, and particularly by sitting upon damp seats while the body is overheated; by impaction of feces, constipation, and straining at stool. Irritating substances swallowed with the food, such as small pieces of bone, oyster-shell, or the stones of fruit, may excite abscess by their presence in the rectum. Among other causes are general debility, an impoverished state of the blood, the scrofulous and tuberculous diatheses. The disease sometimes occurs in quite young infants. Wetherill reports the case of an infant attacked by an enormous ischio-rectal abscess while nursing from the mother, who was at the time suffering from a succession of boils. Many cases have been traced to sitting upon the outside of damp omnibuses. Hepatic disorders, causing engorgement and stasis of the blood in the hemorrhoidal plexus, have frequently occasioned this condition. These abscesses are not always situated in the ischio-rectal fossa; frequently they are subcutaneous and just outside the anus: in other cases the starting-point may be ulceration of the mucous membrane of the rectum, with escape of fecal matter into the areolar tissue; they also originate in the submucous connective tissue of the rectum. The acute abscess is sudden and very severe in its onset; the pain is continuous, throbbing, and augmented during defecation; dysuria is almost always present, and in some cases there is total inability to pass water. There is local tenderness, dusky redness, and fluctuating prominence, and, if not interfered with, a rupture of the integument will take place and the pus will escape externally. Sometimes their formation is accompanied with a chill or with a succession of rigors: there is always considerable constitutional disturbance, febrile movement, loss of appetite, and malaise. This form of abscess is usually circumscribed and does not burrow irregularly, and sudden relief of pain and distress is coincident with their evacuation.

Chronic rectal abscess corresponds to the cold or chronic abscess in other situations: it is apt to occur among those who are much debilitated or among those of the scrofulous diathesis. These abscesses have little disposition to open spontaneously upon the surface, but they burrow extensively in all other directions—high up along the outside of the rectum, laterally into the tissues of the buttock, or downward and forward into the perineum. The process of formation may occupy many months, and sad havoc may be occasioned before their existence is suspected. They occasion no pain nor distress nor acute febrile movement, but may be accompanied with a hectic condition, erratic sweatings, and rapid loss of strength. Upon examination of the anal region in these cases a painless flat, boggy, crepitating enlargement is the only surface-indication of the probably extensive damage sustained by the deeper structures.

This form of abscess may be of traumatic origin, but more frequently the inflammatory process arises in the cellular tissue of the ischio-rectal fossa; in some cases the morbid action is due to ulceration of the rectum. In either case peri-rectal or peri-anal cellulitis will be induced. When these abscesses are of strumous origin the pus is thin, curdy, and offensive.

Both the acute and the chronic abscesses of this region are often difficult to heal, the external opening remaining permanently patulous, communication with the bowel resulting from internal burrowing and erosion, with the formation of extensive sinuses in all directions, resulting in fistulæ in ano.