Patient presents with this condition not knowing that the underlying cause is ulceration. Stool may vary from 3 to 20 per day, accompanied by great straining and tenesmus, exhausting the patient and causing rapid loss of weight. The cause is due to the contact of feces with exposed nerve terminals, which excites and increases peristalsis. One peculiar characteristic of the diarrhea in ulceration of the rectum is that it is generally quiescent at night, whereas during daytime, the patient suffers from frequent calls to stool.

Pain is a very unreliable and indefinite symptom in ulceration of the rectum. Patient may have no, little, or severe pain, depending on the site and cause of ulceration. If the ulceration is high up in the rectum, a sense of heaviness and aching in the sacral region is the chief discomfort of which most patients complain. If it is situated lower down within the sphincters and involves the mucocutaneous area where the sensitive nerve ends enter, pain of a sharp, lancinating, or burning character will be the chief symptom.

Painful ulceration is usually due to recurrent genital herpes, syphilis (in endemic areas), or trauma. Severe pain is seen in perianal herpes simplex infection (usually interstitial) or perianal abscess. More recently, lymphogranuloma venereum has emerged as a major cause in Western countries. Painless ulcers are associated with syphilitic chancre, although HSV and trauma must be kept in mind (Russell 2011).

The pain of anal fissure may be constant or intermittent, usually most severe during or immediately after stool passage. In the intervals of defecation, there is a dull aching, which may be confined to the rectum or extend up to the back and down the limbs. The patient may prefer standing during consultation or sit gingerly and walk with a wide-based, tentative gait.

Hemorrhage is always present in a greater or lesser degree, depending upon the location and the extent of the ulceration. It may be slight so that the discharges may only be tinged with a streak of blood. On the other hand, it may be profuse, if a large vein or artery is attacked by the ulcer.

Besides blood, there is discharge of mucus and pus in varying quantities. Discharge increases as ulcers increase in size and number. The discharge is sticky, reddish in color, and of the consistency of pus with fragments of necrosed tissue and constantly oozes out of the anus.

In case of long-standing ulcers, there will invariably be pruritis around the anal margin. This may extend in any direction until many deep fissures are to be seen. It usually subsides when the ulceration has been cured.

Endoscopic appearance of most of the ulcer is nonspecific, and histopathology provides the only means of definitive diagnosis.

The number, size, and location of the ulcers can be seen by proctoscope or flexible sigmoidoscope. An ulcer may be shallow or deep and is often not initially apparent, being concealed under the radiating mucous folds. It can be clearly seen only by drawing back the skin of the perianal region.

Morphologically tubercular ulcer presents in seven forms: fistula in ano, ulcer with sharply defined undermined edges, rectal stricture, multiple small mucosal ulcer, lupoid form of submucosal nodule, mucosal ulcer, and verrucous form with multiple warty lesions.

The macroscopic appearance of typical SRUS ulcer is a small, shallow lesion with white slough or a hyperemic mucosal patch, usually on the anterior wall of the rectum. Endoscopic spectrum of SRUS varies from hyperemic mucosal patch to small or giant ulcers to broad-based polypoid lesions of different sizes. Usually the lesion is 5–10 cm from the anal verge. The ulcers may range from 0.5 to 4.0 cm in diameter but usually are 1–1.5 cm in diameter.

Syphilitic and chancroid ulcers are initially superficial and multiple situated anteriorly at mucocutaneous junction and are painful. These are generally smooth, sloping, and non-indurated. In late stages, there may be mucosal fissure which may heal with fibrosis and stricture formation.

The varicose ulcers appear as sharply defined, irregular depressions in the mucous membrane of the rectum. The edges are slightly elevated, and the bases are covered with a yellowish pus, beneath which are bright-red granulation tissues. The veins of the rectum surrounding the ulcerated portion and, in general, all over the rectum are varicose, and when the patient strains, they become largely dilated.

Hemorrhoidal ulcers are entirely distinct from varicose ulcerations. The hemorrhoidal ulcerations are usually fissure-like cracks or splits through their center, in a protruding stump from which the hemorrhoid partly sloughed away due to thrombosis, trauma, or corrosive injections.

Ulcers in acute hemorrhagic rectal ulcer syndrome (AHRUS) are small, shallow, and irregular or circumferential and situated in the terminal rectum immediately proximal to the dentate line, occupying from one-third to the entire circumference of the rectum.

On examination, AIDS ulcers are differentiated by their location proximal to the dentate line with a broad based which may dissect between tissue planes.

Ulcerative colitis patients have diffuse erythema, attenuated vascular pattern, friability, erosions, and multiple superficial ulcers.

Crohn’s disease patients have aphthous ulcers which are longitudinal with normal intervening mucosa, cobblestone appearance, stricture, fistula, or pseudodiverticular formation.

Traumatic ulcers consist of simple granulations, neither nodular nor proliferating bathed in thick white milky secretions containing pus cells and bacteria.

Anorectal function tests have been performed, but the results are variable, and the tests do not help in establishing the diagnosis or predicting therapeutic response.

In the early stages of inflammatory disease, the diagnosis can be helped by bacteriology of stool. The appearance of granulomas, fissures, and transmural inflammation of anal lesion indicates Crohn’s disease. A nonspecific inflammation is a feature of ulcerative colitis or postirradiation proctitis, which may be distinguished by history alone. If rare organisms are cultured, such as cryptosporida or viruses, the possibility of immune disease (e.g., HIV or leukemia) should be considered. The history of sodomy and anal intercourse should be elicited. These sometimes present with multiple fissures and anal abscess.

Ischemia rarely affects the rectum but when present is usually in older age groups and is of sudden onset and associated with profuse bleeding and abdominal pain. The ulcers of SRUS are palpable and feel indurated with fixity to extrarectal tissues. Biopsy is essential to distinguish it from malignant causes (Ellis 2011). The crucial part is not to miss a malignant rectal ulcer in its early stages, and even few “unwanted” biopsies may be indicated.

Anal fissure is a longitudinal ulcer in the anoderm extending proximally to the dentate line and distally to the anal verge. It may present as acute fissure with severe excruciating pain or may present in the chronic form, characterized by a skin tag distally (sentinel piles), hypertrophied papilla proximally, and the base of ulcer showing the transverse fibers of the sphincter. The pain is exaggerated on defecation and may be accompanied with streaks of blood. Blood is scanty and bright red. The topic is described in detail in a separate chapter of this book.

This type of anorectal ulcer is caused by sloughing and ulceration of a well-defined hemorrhoidal mass. This may be due to thrombosis followed by necrosis, trauma from the passage of hard fecal masses or foreign bodies, or strangulation. It may also be produced by the application of ice in order to relieve congestion and by the action of corrosive substances applied to the surface or injected into the body of the hemorrhoid for the purpose of curing it. The symptoms of this variety of ulceration are a history of the existence of hemorrhoids either internal or external and of prolapse, strangulation, efforts at reduction, and the application of ice or cauterizing agents. Morning diarrhea may or may not be present, but the patient is frequently awakened at night by the spasmodic contraction of the sphincter and the desire to defecate.

Treatment is absolutely and unequivocally surgical. The sphincter is dilated, and the ulcerated hemorrhoidal mass is taken away either by crushing the clamp and cautery or by ligation.

The clamp-and-cautery operation by its stimulating effect and bactericidal action seems to be as near a specific as one can desire.

This is a chronic, intractable ulcer which occurs in patients with varicosity of the rectal mucous membrane. Their chronicity is due to varicosities of the superior hemorrhoidal veins. This is different from the ulceration of the hemorrhoids in the fact that it is chronic. Exciting cause is some wound or injury to the mucous membrane or rupture of one of the varicose veins. Infection takes place and causes the ulceration. Heavy eaters and drinkers who do little exercise and are inclined to constipation are predisposed to this type of ulceration.

The ulcers occur above the mucocutaneous border and produce few symptoms other than the frequent desire to defecate, more marked during daytime. There is always an inclination to defecate immediately upon rising in the morning, which generally results in the passage of small quantities of mucus and pus, with or without blood. Occasionally these patients suffer from quite severe hemorrhages. There is a dull aching pain, but when the ulcers invade the mucocutaneous tissue at the margin of the anus, the patient may suffer from acute pain. In this condition, spasm of the sphincter will also complicate the ulceration.

The treatment of varicose ulcers of the rectum is very tedious and unsatisfactory. At the same time, it is almost impossible for these ulcers to heal without absolute rest in bed. The diet should be regulated so as to contain as little refuse material as possible.

Extrapulmonary tuberculosis (TB) accounts for less than 15 % of all cases of tuberculosis, while the intestinal one alone constitutes less than 1 % of extrapulmonary forms of the disease. The most common morphological form of anal TB is the ulcerative form which typically presents as a superficial ulceration, with a hemorrhagic necrotic base that is granular and covered with thick purulent secretions of mucus.

The postulated mechanisms by which the tubercle bacilli reach the gastrointestinal tract are (i) hematogenous spread from the primary lung focus in childhood, with later reactivation; (ii) ingestion of bacilli in sputum from active pulmonary focus; (iii) direct spread from adjacent organs; and (iv) through lymph channels from infected nodes.

The chief complaints are fever, anorexia, and weight loss. The fever is low grade, intermittent, and not associated with chills and rigor, and it seldom crosses 101°F. Passage of fresh blood in stools, anal pain or discharge, and multiple or recurrent fistula in ano and perineal ulcerations are not characteristically distinct from other anal lesions especially Crohn’s. In developing countries of the world, tuberculosis is common. The incidence of tuberculosis in Western European countries has decreased in the past few decades. There are four types of anal and perianal tuberculosis, ulcerative, verrucous, lupoid, and military, but the most common is the ulcerative type. It may be due to focus in the lung or intestine, or it may be primary. Positive diagnosis of anal TB relies on both histological and bacteriological assessments.

Venereal ulcers of the rectum are common in societies where sodomy is practiced. The congenital cases with a rectal ulceration are rarely encountered. In the acquired group, syphilitic ulcers may occur in the primary stage or as a result of breakdown of a gummatous rectal lesion. It may also be seen in the perianal region and mucocutaneous area. Mucous patches are infective and are relatively painless. When involving the anus, the inguinal lymph node may show the typical firm, discrete, and shotty appearance.

The incidence has increased, particularly due to unprotected anal intercourse. Rectal syphilis is often missed because it is usually asymptomatic or causes only mild symptoms. Rectal syphilis is one of the great masqueraders due to its variable symptoms including itching, bleeding, tenesmus, urgency of defecation, and anal discharge, which may be purulent, mucoid, or blood stained. However, instances of rectal syphilis extending between the anal verge and dentate line have been reported. The rectal chancre shows diffuse chronic inflammatory cell infiltration predominantly composed of plasma cells in the lamina propria and some blood vessels (hematoxylin and eosin stain, ×200). Large numbers of spirochetes are present on a special staining of the rectal biopsy specimen (Warthin-Starry stain). The patient is treated with one dose of intramuscular benzathine penicillin G of 2.4 million units, and a single dose of penicillin therapy induces rapid regression of the rectal ulcer.

Dysentery, while it may, and often does, involve the whole of the large intestine, has its seat most frequently in the sigmoid flexure and rectum. It is in the lower portions of the alimentary canal that its chronic results occur. This is logistically suggested by the fact that all of the detritus and infectious bacteria are discharged, carried down by the peristaltic action of the gut into these lower segments, as a result of acute, sporadic, or epidemic dysentery. Chronic circumscribed ulcers of the rectum or sigmoid with the typical symptoms of diarrhea, pus, blood, and mucus in the stools occur. These symptoms accompany all forms of rectal ulceration from whatever cause they arise and render it difficult to distinguish a true dysenteric ulceration from other varieties. Indeed, ulcerations of the rectum and sigmoid are often mistaken for chronic dysentery. The presence of the amebic dysentery or the bacillus of Shigella will positively establish the dysenteric nature of any given ulcer. It begins as infiltration of the mucous membrane with a fibrous exudation. This infiltration increases until it interferes with the blood supply of the mucous membrane, the latter sloughs and is cast off, and an ulceration results. If this slough is superficial, the membrane may be soon restored to its normal condition, but if the infiltration is deep and involves the submucous tissues, the loss of substance is more extensive and cicatrization and stricture of varying degrees may result. The ulcers may be small and localized, or they may extend over large areas and sometimes entirely surround the canal; they may be trough-like, stellate, or irregular in shape; they may be single or multiple. Perforation has been known to occur, but it is not a frequent accident to find rectal stricture having followed dysenteric ulceration. A large number of pharmacological agents starting with emetine, chloroquine, metronidazole, tinidazole, diloxanide furoate, secnidazole, etc., are available to manage these cases.