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evacuation, and severe straining during defecation.

b.The syndrome occurs in women nine times more often than in men.

c.Normal function of the colon is demonstrated by colonic transit time, which is measured by following radiopaque markers through the colon.

d.Diagnosis may be confirmed by defecography, which demonstrates the failure of the muscle to relax appropriately. Another simple diagnostic test reveals the inability of the patient to expel an air-filled balloon from the rectum.

e.Treatment is nonsurgical. Biofeedback to develop cognitive aspects of defecation is the treatment of choice.

3.Internal intussusception (internal prolapse of the rectum). This condition is characterized by the distal bowel telescoping into itself to cause partial obstruction to defecation. Patients complain of an urgency to defecate, a feeling of rectal fullness, and pelvic pain.

a.A solitary rectal ulcer is now recognized as the cause of this syndrome.

1.The ulcer is usually located in the anterior rectal wall. Biopsies reveal a bland, non-neoplastic ulcer.

2.Colitis cystica profunda, which is characterized by glandular tissue beneath the mucosa, may accompany this condition. It is important to distinguish this benign lesion from cancer (for which it may be confused by histologic appearance).

b.Internal intussusception is accompanied by abnormal rectal fixation, which permits the rectum to descend toward the perineum.

c.Medical treatment suffices for most patients and consists of:

1.Increased dietary fiber

2.Stool softeners

3.Glycerine suppositories or small enemas

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d.Indications for surgical treatment include:

1.Debilitating symptoms despite maximum medical therapy and psychological counseling

2.Impending anal incontinence due to stretch injury to the pudendal nerves caused by constant straining (and subsequent perineal descent)

3.Chronic bleeding from a solitary rectal ulcer

e.Surgical treatment is low anterior resection of the sigmoid and proximal rectum, with colorectal anastomosis and rectal fixation.

4.Rectal prolapse is the protrusion of the full thickness of the rectum (and occasionally the sigmoid colon) through the anus. This condition should be distinguished from mucosal prolapse, which is the protrusion of only the rectal mucosa through the anal orifice. Full-thickness prolapse has concentric mucosal folds. Mucosal prolapse has radial folds in prolapsing mucosa.

a.Etiology and epidemiology

1.Rectal prolapse may be the result of long-term internal intussusception.

2.There is an increased incidence in:

a.Patients in mental institutions

b.Women who have had a hysterectomy

c.Elderly women

3.There is no increased incidence in women who have had multiple deliveries.

b.Symptoms include:

1.Mucosa-lined bowel protruding through the anus

2.Bleeding

3.Anal pain

4.Mucous discharge

5.Anal incontinence of varying degrees, caused by stretch of the anal sphincters or by stretch injury to the pudendal nerves (from perineal descent that is associated with the prolapse)

c.Treatment is surgical. The prolapse may become incarcerated and strangulated if not reduced.

1.Patients in satisfactory health and with satisfactory anal continence should be treated by low anterior resection with rectopexy.

2.An alternative treatment is to fix the rectum to the sacrum with a synthetic sling (Ripstein's procedure). This operation may increase the difficulty of evacuation.

3.Patients who are poor surgical risks may be treated by perineal proctectomy with low colorectal (or coloanal) anastomosis. An abdominal incision is avoided, but recurrence is higher.

4.Anal encircling procedures are at times advocated for poor-risk patients. A band of synthetic material (wire or mesh) is placed subcutaneously around the anus. Encircling procedures are often complicated by infection, and results are generally unsatisfactory.

5.Patients with total incontinence may require treatment by anterior resection of the rectum and colostomy (low Hartmann's procedure).

XII Benign Anorectal Disease

AHemorrhoids

1.Etiology

a.Anal cushions are complexes of vascular and connective tissue normally located in the right anterolateral and posterolateral positions and the left lateral position in the anal canal. This normal tissue protects the sphincter during defecation and permits complete closure of the anus during rest.

b.Engorgement of the vascular tissue in the anal cushions causes these complexes to enlarge and form hemorrhoids.

c.Prolonged straining during defecation and increased abdominal pressure are thought to contribute to formation of hemorrhoids.

2.Classification

a.Internal hemorrhoids are located above the dentate line and are covered by rectal mucosa.

1.First-degree hemorrhoids bleed but do not prolapse.

2.Second-degree hemorrhoids bleed and prolapse through the anus but reduce spontaneously.

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3.Third-degree hemorrhoids bleed and prolapse and must be manually reduced.

4.Fourth-degree hemorrhoids protrude through the anus and cannot be manually reduced.

b.External hemorrhoids reside below the anal verge and are lined by squamous epithelium. A thrombosis within an external hemorrhoid may cause acute swelling and anal pain.

3.Symptoms

a.Bleeding, mucous discharge, prolapse, and pruritus are symptoms of internal hemorrhoids.

b.Internal hemorrhoids seldom cause pain unless acutely prolapsed and incarcerated. Anal pain should not be

attributed to thrombosed internal hemorrhoids. Another source must be sought to explain the pain.

4.Treatment of hemorrhoids depends on the symptoms.

a.Medical therapy consists of the addition of dietary fiber and stool softeners and education of the patient to avoid prolonged straining.

b.Rubber band ligation can provide satisfactory treatment for firstand second-degree hemorrhoids and selected cases of thirdand fourth-degree hemorrhoids.

1.The rubber bands must be placed above the dentate line, or severe pain will be associated with the procedure.

2.External hemorrhoids are not amenable to this form of treatment.

c.Sclerotherapy (submucosal injection of phenol in oil or sodium morrhuate) may be used for firstand seconddegree hemorrhoids.

d.Infrared photocoagulation is accomplished by placing an infrared probe proximal to the internal hemorrhoids and delivering therapy in three pulses of 1.5 seconds each. This treatment has been successful for first and second-degree hemorrhoids.

e.Hemorrhoidectomy, which may be required to relieve the symptoms of thirdand fourth-degree hemorrhoids may be performed by:

1.Surgical excision of all hemorrhoidal tissue, leaving the mucosa open or sutured closed.

2.Stapled hemorrhoidectomy, which removes a ring of anal rectal tissue above the hemorrhoids, severing the blood supply and lifting and flattening the hemorrhoids in the anal canal.

f.Thrombosed hemorrhoids may require excision for relief of pain. However, most cases resolve within 2 weeks without any specific therapy. The most intense pain is within the first 48 hours after thrombosis; thereafter, pain usually subsides rapidly.

B

Anal fissure is a tear in the anoderm, which is usually caused by constipation and, less often, repeated episodes of diarrhea. This leads to excessive tension in the internal anal sphincter and sesequent ischemia of the muscle with overlying anoderm breakdown. The fissure is located near the posterior midline of the anus 98% of the time in men and 90% of the time in women. Otherwise, the fissure is near the anterior midline.

1.Symptoms are anal pain and bleeding associated with defecation.

2.Physical findings may include the following:

a.Fissure or ulcer distal to the dentate line

b.Sentinel skin tag at the anal verge adjacent to the distal edge of fissure

c.Hypertrophied anal papilla at the proximal edge of the fissure

d.Spasm of the internal sphincter (in chronic cases)

3.Treatment

a.Medical (most fissures will heal with medical treatment)

1.Stool softeners, increased dietary fiber, and warm sitz baths are beneficial.

2.Suppositories are usually not beneficial.

3.Topical application of 0.2% nitroglycerin ointment has been shown to be effective treatment in some patients by increasing blood flow to the ischemic internal sphincter muscle.

4.Botulinum toxin injection into the internal sphincter muscle. This causes temporary paralysis of the muscle, allowing the fissure to heal.

b.Surgical (indications are persistent symptoms despite medical treatment)

1.Lateral internal sphincterotomy. This procedure may be done by either an open or a closed technique and is highly curative.

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2.Anal sphincter stretch. This procedure is done under local anesthesia and is also effective. This approach may be associated with a slightly higher risk of incontinence than the risk with lateral sphincterotomy.

C Anorectal abscess and fistula

1.Pathogenesis

a.These infections are cryptoglandular in origin: They begin in the anal glands that empty into the anal crypts.

b.An abscess is the acute stage, and a fistula is the chronic stage of the same disease process.

c.Most abscesses originate between the internal and external sphincters and are thus called intersphincteric abscesses.

1.Downward extension results in perianal abscess.

2.Lateral extension through the low external sphincter results in an ischiorectal fossa abscess.

3.Upward extension (rare) results in supralevator abscess.

2.Signs and symptoms

a.Anorectal pain is constant but is not associated with defecation.

b.Swelling and fluctuance are late signs.

c.Drainage of pus and blood signifies spontaneous rupture of the abscess and is usually associated with pain relief.

d.Fever and leukocytosis may be present.

3.Treatment is incision and drainage and should be done when the diagnosis is made. Treatment with antibiotics is inappropriate.

a.The ischiorectal fossa may contain a large volume of pus before fluctuance is obvious.

b.Antibiotics are not required unless immune status is compromised (e.g., diabetes, leukemia).

c.Incision and drainage are curative 50% of the time; the other 50% of patients will develop anorectal fistula.

4.Anorectal fistula is a communication between an anal crypt (internal opening) and the perianal skin (external opening).

a.The internal opening must be identified to allow proper treatment.

1.The most common site of the internal opening is the posterior anal crypt.

2.Anterior abscesses may originate from anterior anal crypts.

3.Goodsall's rule states that external openings posterior to a transverse line that bisects the anus will connect to the posterior midline crypt; external openings anterior to this line will communicate to an anterior crypt by a short, direct tract.

4.Exception to Goodsall's rule. An anterior external opening greater than 3 cm from the anal margin usually communicates with the posterior midline crypt.

b.Treatment of simple anal fistula is to identify both openings and open the tract by fistulotomy.

c.A complicated fistula that tracks above the external sphincter may require a procedure that eradicates the internal opening.

1.A fistulotomy can cause incontinence.

2. A flap of rectal mucosa is used to close the internal opening in these rare cases.

D Pilonidal disease

1.Pathophysiology. Pilonidal disease is characterized by hair from the skin of the postsacral superior gluteal cleft that drills below the skin level, causing foreign body reaction and localized infection.

2.Treatment

a.Incision and drainage of acute abscesses

b.Excision with closure by secondary intention of chronic sinus tracts

1.Healing may be promoted by marsupialization of the sinus.

2.Excision and primary closure of the sinus are accompanied by a high incidence of recurrence.

E

Hidradenitis suppurativa is an infection of the apocrine sweat glands. The infected glands form subcutaneous sinus tracts that can spread to the perineum, scrotum, or labia.

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1.Pathophysiology. The disease should be distinguished from cryptoglandular disease.

a.Hidradenitis suppurativa does not involve the anal canal because there are no apocrine glands in anoderm.

b.Cryptoglandular disease originates in the anal canal.

2.Clinical presentation is numerous, often complicated fistulas and sinus tracts around the anus.

3.Treatment is excision of involved skin, with healing by contracture. Recurrence is common and should be treated by prompt excision.

F Condyloma acuminatum

(genital warts)

1.Etiology. The causative agent is the human papillomavirus (HPV).

a.Transmission is usually sexual, with increased incidence in patients who practice receptive anal intercourse.

b.There is an increased incidence in male homosexuals.

c.Certain viral strains (HPV-16 and HPV-18) found in condyloma are associated with an increased risk of anal cancer.

2.Clinical presentation. The lesions vary from tiny excrescences to cauliflowerlike masses. They may be sessile or pedunculated, and they are usually located on the perianal skin, penis, vulva, vagina, or cervix or in the anal canal. Pruritus, anal wetness, discomfort, and the presence of a mass are the usual symptoms.

3.Treatment

a.Bichloroacetic acid is applied topically to lesions every 7 days.

b.Local excision and electrocoagulation with local anesthesia may also be performed and offers the best chance of cure.

c.Interferon has been suggested for refractory warts.

d.Patients should be followed closely because of the risk of associated cancer if carcinogenic viral strains are identified.