Where there are numerous external openings it is necessary to probe all of them so as to determine whether they are connected and the direction which they take. Sometimes more than one inter nal orifice exists.
The presence of an incomplete rectal fistula is more difficult to determine than the other varieties of this lesion which have just been considered. It is the most painful form, but fortunately it is of in frequent occurrence. Its orifice may be located anywhere in the rectum, but it is generally found between the internal and the external sphincters. According to the Allinghams, the circumference of this opening is often as large as an Eng lish three-penny piece, its edges being sometimes indurated, at other times un dermined. The faces when liquid pass into the sinus and create great suffering —a burning pain often lasting all day after the bowels have acted. In this variety of fistula the fasces are coated more or less with pus or blood and a boggy swelling is noticed at some portion of the circumference of the anus. A peculiar feature of this swelling is often noted, viz.: its presence one day and its disappearance in a day or two, followed by an increased discharge of pus from the bowel. This is explainable by the closure of the outlet of the fistula caused either by a plug of faeces or as a result of inflammatory swelling which allows the collection of a quantity of pus and the consequent formation of the boggy tu mor. The swelling disappears upon the re-establishment of the communication between the bowel and the sinus, and is attended by the profuse discharge of ter previously mentioned. This phenom enon is repeated over and over again, and, as a rule, is a pretty positive indication as to the nature of the disease. In some cases of blind internal fistula, if the ori fice can be felt or if it can be seen through a speculum, a bent probe may be introduced into it and made to pro trude near to the cutaneous surface of the body, where its point can be felt.
Fistulae frequently co-exist with other rectal diseases; it is, therefore, important that an examination should be care fully made, so as to exclude such lesions as stricture, malignant or benign; orrhoids, tumors, etc. A thorough phys
ical examination of the chest should also be made, to ascertain the presence or ab sence of phthisis, which so frequently complicates fistula in ano.
The following observations regarding the relation of fistula in ROO to phthisis are noted: Tuberculous fistula of the anus is usually secondary to phthisis. Pulmonary tuberculosis is rarely, if ever, secondary to anal fistula before or after operation. Tuberculosis of the anal region should be dealt with as radically as when it attacks other organs. When the patient's condition permits, one should operate on fistulie irrespective of kind. Operation should not be declined in persons suffering from chronic phthisis nor in those who give a family history of tuberculosis. Patients oper ated on for tuberculous fistula compli cated by phthisis, and patients who are non-tuberculous, but suffer from some involvement of the lung, and who rapidly decline after the operation, do so from an inflammation of the lunps induced by the especially ether. Such accidents have not followed operations in personal practice where local anres thesia was employed. One is justified in discarding the teachings of writers who teach that the cure of a fistula will re sult in the development of phthisis. S. G. Gaut (Inter. Med. Mag., April, 1002).
Serious kidney disease should be ex eluded before recommending operation, for obvious reasons. In eases of caries of the vertebra?, of the sacrum, or of the pelvis, fistulous tracks may form and simulate anal fistula. In such instances a careful investigation will reveal the true origin of the trouble, and show that the case is not one of ordinary anal fistula.
Etiology. — Fistula in ano, which is not due to ulceration and perforation of the rectal wall from within, is the result of a previous abscess. Such an abscess forms in the ischio-rectal fossa, and al though opened early by a free incision even before the cavity becomes distended with pus, it frequently fails to heal. It may fill up and contract to a certain ex tent, but it does not become obliterated; a narrow track remains, which consti tutes the disease under consideration.