Rectum, the terminal portion of the intestinal canal, named, from its comparatively straight course, the rectum (see DIGESTION), is the seat of various affections requiring medical or surgical assistance. Some of these affections, as fistula, fissure (see ANUS), piles, prolapsus ani, have already been considered. Amongst the other diseases of the rectum of sufficient importance to claim notice in these pages are—
(1) Stricture of the Rectum, which may be either of a simple or malignant nature. Simple stricture consists in a thickening and induration of the submucous tissue, less often of the muscular or mucous coat of the rectum, so as to form a ring encroaching on the calibre of the tube. It is situated most often about an inch from the anus, and the con- traction is so great and unyielding that it is often difficult to pass a finger through it. It may occur as the result of injury or operation, of old ulceration (e.g. from dysentery), of syphilis, or without ascertainable cause. The symptoms are constipation and great pain, and a straining in evacuating the faeces, which, if not liquid, are passed in a narrow, flattened, or worm-like form that is very significant of the nature of the case. In an advanced stage of the disease diarrhoea and prolapsus often supervene. However great may be the constipation, strong purgatives must be altogether avoided. Soft and unirritating evacuations must be procured by such medicines as the confection of senna combined with sulphur (see PILES), or injections of castor-oil or of tepid water. The diet should be regulated so as to assist the action of the medicines. Nutritious soups are serviceable, since, at the same time, they support the strength and leave little matter to be excreted. Gradual dilatation by suitable bougies often gives great relief, but must be steadily persevered with, as the contraction is almost certain to recur. Malignant stricture—most commonly due to the scirrhous, but sometimes to the epithelial form of cancer—is by no means a very rare affection. Until ulceration sets in the symptoms are like those of simple stricture, only exaggerated in degree; but afterwards there is a discharge of fetid muco-purulent matter streaked with blood. In this disease the treatment can, in most cases, be only palliative. Sometimes, however, if the tumour is low down and localised it may be removed with at least temporary relief. If complete obstruction occur, or is threatened, the surgeon may resort to the formation of an artificial anus in the loin or groin as a last resource.
(2) Spasm of the sphincter ani muscle is characterised by extreme pain in the region of the anus, especially when an attempt is made to evacuate the bowels. The muscle contracts so firmly that the surgeon cannot easily introduce the finger into the rectum. The spasm may be caused by piles, by fissure of the anus, by ulceration of the rectum, and sometimes apparently by mere constipation. It is often relieved by the application of the belladonna ointment of the British Pharmacopoeia.
(3) Neuralgia of the rectum, known also as proctalgia, is sometimes met with, and is especially prone to attack children and gouty persons. It is usually relieved by the judicious use of aperient medicines and such treatment as is used for other forms of Neuralgia (q.v.).
(4) Pruritus podicis, or itching of the anus, is a very common and extremely troublesome affection. Sometimes it depends on the presence of threadworms, of old piles, constipation, or some other local cause of irritation, while in other cases it is one of the manifestations of some constitutional condition. The treatment must depend upon the exciting cause. See works on the rectum by Allingham, Cripps, Henry Smith.