Nearly everyone has experienced anorectal discomfort. Our low-fiber diet, which results in small, hard stools; our lifestyle, which restricts the opportunities for defecation; and our erect posture, which promotes engorgement of the hemorrhoidal plexus, all combine to make anorectal problems virtually ubiquitous. The anorectum also is the site of local manifestations of more generalized disorders, such as inflammatory bowel disease. Finally, because the rectum is a sexual organ for some people, sexually transmitted diseases may occur at that site.
- Pathogenesis. An anal fissure is a tear in the lining of the anus, usually resulting from the difficult passage of hard stool. Some fissures are a consequence of a more generalized bowel disorder, such as Crohn’s disease. Others result from the trauma of anal intercourse or insertion of foreign bodies. Rarely, carcinoma of the anus presents as an anal fissure. More than 90% of fissures that are not associated with Crohn’s disease occur in the posterior midline. The remainder occurs in the anterior midline. Fissures associated with Crohn’s disease may occur at any location within the anal canal.
- Clinical presentation. Anal fissures are painful, and the pain is exacerbated by the passing of stool. The pain may lead to a cycle of retention of stool, formation of hard stool, passage of hard stool, and aggravation of the fissure. Bleeding and itching also are common. Anal fissures often coexist with hemorrhoids.
External examination by spreading the patient’s buttocks and anal orifice may reveal the fissure. Digital examination usually is quite painful for the patient and thus the rectal examination may be limited. Sometimes the fissure or a mass of granulation tissue can be palpated. Preliminary application of a topical anesthetic decreases the discomfort of the digital rectal examination and subsequent sigmoidoscopic examination.
Anoscopy and sigmoidoscopy should be performed to make the definitive diagnosis and to rule out other conditions, in the discussion of hemorrhoids.
Scraping the fissure. If the cause of the fissure is suspected to be sexual, a scraping of the fissure should be examined under dark field illumination to consider the possibility of a syphilitic lesion.
Radiologic evaluation. Patients whose fissures fail to heal or who have fissures that are not in the midline should undergo radiologic evaluation of the large and small bowel for Crohn’s disease.
The treatment of anal fissure is similar to that of hemorrhoids: high-bulk diet, stool softeners, warm baths, and lubricating suppositories. Most fissures heal on this regimen. Chronic anal fissures that are not due to inflammatory bowel disease may require dilatation of the anus, sphincterotomy, or excision of the fissure.
Fistulas and abscesses
- Pathogenesis. A fistula is a tract lined by inflammatory tissue that usually has an opening through the mucosa of the anus or rectum and another opening in the perianal skin. Sometimes only one opening is evident. Fistulas are always infected with local organisms. An abscess is a collection of pus within the perianal or perirectal tissues, which may or may not be associated with a fistulous tract. Factors that predispose to fistula or abscess formation include local infection of the anal crypts, Crohn’s disease, trauma, cancer, and venereal disease.
- Clinical presentation and diagnosis. A fistula or abscess may be painful and cause fever. If the fistula is external, drainage of pus, mucus, or stool may be evident. Physical examination may confirm the external location of the fistula opening. A tender, firm, or fluctuant mass suggests an abscess. Anoscopy, sigmoidoscopy, and barium-contrast studies.
- Treatment. Although local treatment with warm baths, high-fiber diet, and stool softeners may be palliative, definitive surgical drainage of the abscess or excision of the fistula usually is indicated. An exception is a fistula associated with Crohn’s disease, which may respond to an elemental diet, metronidazole, or steroid therapy. Broad-spectrum antibiotics are indicated for patients with fever, elevated white blood cell count, or signs of systemic toxicity.
- Pathogenesis. Rectal prolapse ranges in severity from prolapse of a small portion of rectal mucosa to protrusion of the entire rectal wall through the anus (procidentia). Straining at stool is thought to be causative, but pelvic surgery, childbearing, and weak pelvic musculature are contributive factors.
- Clinical presentation and diagnosis. Patients with rectal prolapse complain of bleeding, passage of mucus, and irritation of the exposed mucosa. In some patients, prolapse of the rectal mucosa or of a substantial portion of the rectum may be observed. Other patients must strain to produce the prolapse. Poor anal sphincter tone usually is evident on digital examination. Sigmoidoscopy and, in most patients, barium enema are indicated to define the extent of irritated mucosa and to rule out associated conditions.
- Treatment. If the prolapse is mild and confined to the mucosa, the treatment regimen is the same as for hemorrhoids. However, frank procidentia requires operative treatment if the surgical risk is good.
- Pathogenesis and clinical presentation. Proctalgia fugax is fleeting pain in the rectum. The pain is intense, develops suddenly, and typically lasts for seconds to minutes, although occasionally it persists for several hours. There is no known cause. It probably is related to spasm of the musculature of the rectosigmoid or levator muscles. Rarely, it is associated with mucosal inflammatory disease or colonic tumors.
- The diagnosis is made by the typical history of rectal pain and absence of physical findings. Rectal and sigmoidoscopic examinations should be performed to rule out other treatable disorders.
- Treatment is symptomatic, consisting of warm baths and, if symptoms are frequent, analgesics and muscle relaxants. Because of the transient nature of the disorder, however, it is often difficult to determine whether treatment has been effective. The condition usually resolves spontaneously.
- Pathogenesis. Virtually everyone has experienced perianal itching. When the itching becomes frequent or constant, patients seek medical attention. The causes of pruritus ani are legion, including hemorrhoids, fissures, skin disorders, infections, parasites, neoplasms, excessive moisture, excessive dryness, irritation from soap and other agents, and psychoneurosis.
- Clinical presentation. When patients complain of perianal itching, a careful history of bowel habits, stool-wiping technique, use of cleansing or other local agents, and ingestion of antibiotics should be obtained. Examination may be normal or may reveal erythema, excoriations, or maceration of the perianal skin.
- Diagnostic studies. Rectal and sigmoidoscopic examinations should be performed. Stool culture, examination of the stool for ova and parasites, and examination of the perianal skin for pinworms or Candida are performed when clinically indicated.
Treatment depends on the diagnosis. If no specific cause can be determined, the patient is advised to avoid all topical agents that might irritate the anus and to consume a high-fiber diet. Patients should wipe the anus gently, not vigorously, after defecation, using a moist cotton ball or cotton cloth. Calamine lotion or a steroid cream (not ointment) may be applied to the anus several times a day.
- Pathogenesis. Tumors of the anus sometimes are confused with other inflammatory and infectious lesions. The most common anal tumor is epidermoid carcinoma, but adenocarcinoma and malignant melanoma also can occur.
- Clinical presentation and diagnosis. Patients complain of anal pain, bleeding, itching, or presence of a mass. They may think that they are having more trouble with their hemorrhoids. The diagnosis of neoplasm is suspected by visual inspection, digital examination, and anoscopy; it is confirmed by biopsy. A search for local extension and metastatic disease is warranted. This typically includes routine liver tests, chest x-ray, and computed tomography of the abdomen and pelvis.
- Treatment. Small anal tumors can be treated by local excision. More extensive lesions require the addition of radiation therapy or chemotherapy, or an abdominoperitoneal resection of the rectum and anus.
Sexually transmitted anorectal infections.