John W. Harmon
Christopher L. Wolfgang
Anorectal disorders are often encountered in an ambulatory practice. The four most common—pruritus ani, anal fissure, hemorrhoids, and perirectal abscess/fistula—are discussed in some detail in this chapter. Also included, because of their importance to the primary care provider, are less common disorders such as proctalgia fugax and rectal prolapse. The final section addresses sexually transmitted and other infectious diseases of the anus and rectum. Chapter 102 and Section 17 discuss cutaneous disorders that involve the perianal area and perineum. Chapters 35 and 45 discuss other conditions that may affect the rectum.
Pruritus Ani
Pruritus ani, a distressing perianal itch, is more common in men than in women. It varies in intensity but usually is greatest at night. The itching often abates spontaneously, only to recur after variable asymptomatic periods.
Pruritus ani is a symptom, not a disease. Although 50% to 75% of the time the cause is unknown, the symptom may be a manifestation of a myriad of anorectal disorders (Table 98.1). Of these, anal neoplasia is the most serious cause that must be ruled out, especially in older adults. The itching is most often associated with macerated skin,
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often complicated by excoriation and secondary infection. These changes may be caused by fecal contamination or excessive cleansing efforts, exacerbated by scratching.
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TABLE 98.1 Causes of Pruritis Ani |
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Diagnosis
When a patient complains of perianal itching, several specific historical points should be obtained and several observations should be made to aid in establishing a diagnosis.
History
Dietary history should include information on intake of milk, caffeine (coffee, tea, colas), chocolate, tomatoes, and spices; excessive consumption of any of these can lead to pruritus ani. Medications that cause gastrointestinal (GI) irritation (e.g., laxatives, colchicine) and certain antibiotics (especially tetracycline) can also cause perianal itching, as can chronic diarrhea from any cause. Any history of tissue protrusion or incontinence should be noted. Lastly, personal stress is a major contributing factor, and a careful personal history should be elicited.
Physical Examination
The patient's skin should be examined for signs of a dermatologic problem, such as psoriasis or contact or atopic dermatitis, or a fungal infection (Table 98.1).
With the patient in the lateral decubitus or knee-chest position and the buttocks separated, the perianal area is inspected. During the inspection, the patient should be asked to strain or bear down. This maneuver may demonstrate prolapse or incontinence.
If skin lesions are identified, appropriate evaluation (e.g., a potassium hydroxide preparation) to establish a diagnosis (e.g., Tinea, Candida) should be done to initiate definitive therapy (see Chapter 117). In children up to age 14 years, and in adults who live in households with infected children, the evaluation should include several cellophane tape preparations in an attempt to demonstrate the ova of pinworms (see later discussion).
Digital rectal examination should always be performed using a well-lubricated, gloved finger. At initiation of the examination, the patient should be asked to bear down, which minimizes discomfort. Excessive pain localized to a specific area should alert the practitioner to the possible presence of an anal fissure (discussed later). All structures within reach of the finger should be assessed (anus, sphincter, distal rectum, prostate gland, and cervix).
Anoscopy
After rectal examination an anoscopy should be performed. No enema or laxative is required. A well-lubricated anoscope should be inserted gently. The addition of a local anesthetic ointment does little if anything to decrease any discomfort. After removal of the obturator, the rectum should be inspected under adequate light. Visualization of the more distal anal structures is possible only through the side aspect of the instrument as it is slowly withdrawn.
Cellophane Tape Examination for Pinworms
Cellophane tape examination is easily accomplished by the patient at home or by the practitioner in the office. Swabs are commercially available (Pinworm Diagnostic Tapes, Parke-Davis), but they are also easily made by folding clear cellophane tape, sticky side out, over a tongue blade. At night pinworms migrate from the anal canal to the perianal area, where they deposit eggs. Therefore the swab should be obtained on arising, before a bowel movement and before the perianal area is cleansed. The swab is pressed on the anal verge and then afterward the tape is mounted onto a glass microscopic slide. A specimen obtained in this way keeps for several days. The slides should
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be examined under the low-power (10×) objective of the microscope, searching for the typical ova of pinworm (Fig. 98.1).
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FIGURE 98.1. Appearance of the eggs of shape Enterobius vermicularis (pinworm). The egg is approximately 20 to 50 mm and typically has one flattened side. |
Treatment
Most patients with pruritus ani can be diagnosed and treated adequately by the general practitioner. Even if the evaluation is inconclusive except for the identification of excoriation, symptoms can be controlled by simple measures.
Counseling about the factors responsible for pruritus ani should ensure a clear understanding of the potential roles of stress, lifestyle, and diet.
Dietary change should eliminate potentially causative foods and beverages. It may take 2 weeks for the symptom to resolve after diet modification. It will then recur within 48 hours after resumption of the offending food.
Warm sitz baths for 15 to 20 minutes provide excellent temporary relief (e.g., at bedtime). If possible, these should be used several times daily at the outset of symptoms.
Anal cleanliness and dryness are mandatory and must be gentle. Once or twice daily, and after each bowel movement, the perineal area should be cleansed with a plain mild soap such as Ivory and then rinsed with cotton swabs moistened with warm water. Glycerin–witch hazel wipes (Tucks) or diaper wipes may be used unless they cause irritation or burning. After cleansing, the area should be thoroughly dried by blotting, not rubbing, with soft, white, nonperfumed toilet paper (colored or perfumed tissues, which are potentially allergenic or irritating, should be avoided). A handheld blow dryer is a useful alternative.
The perianal area must be kept dry at all times. This is best accomplished by the application of cornstarch powder or plain talc (Johnson's Baby Powder). A thick layer of zinc oxide or A and D Ointment may be substituted but must be thoroughly and gently removed at the time of each cleaning.
Diarrhea or constipation should be controlled (see Chapters 45 and 46). Bulk laxatives such as psyllium preparations (e.g., Metamucil) and stool softeners such as docusate (e.g., Colace) are preferred. They are not irritating, and they tend to absorb mucus, a possible irritant to the sensitive perianal tissue.
The patient should wear cotton underwear to provide better ventilation and should avoid polyester clothing. Prolonged sitting, especially on synthetic materials (e.g., vinyl seats), which prevent proper ventilation, should be avoided. In general, the use of all other creams, ointments, and medications should be discontinued.
For the occasional patient with symptoms severe enough to cause insomnia, an antihistamine with antipruritic and sedative effects such as diphenhydramine (Benadryl), taken before bedtime, may be helpful. On rare occasions it may be necessary to use minimal amounts of 0.5% or 1.0% hydrocortisone cream to control nocturnal itching. This should be viewed as a temporary measure, and the prolonged use of any topical steroid should be avoided.
A patient with idiopathic pruritus ani that is not responsive to these therapies may be referred to a dermatologist or a gastroenterologist. Further evaluation, especially in the older age group, should include the rectum and colon.
Enterobius vermicularis (Pinworm)
If E. vermicularis is identified, all members of the household should be evaluated with the cellophane tape test. The ova are easily disseminated and survive in the environment for up to 3 weeks.
The preferred drugs to eradicate this infestation are mebendazole (Vermox) given as a single dose of 100 mg or albendazole (Albenza) given as a single dose of 400 mg in adults. These drugs should not be used in infants or pregnant women. An alternative is pyrantel pamoate (available over-the-counter in an oral suspension as Pamix, Pin-X, or Reese's Pinworm Medicine), which is also given as a single dose. All of these treatments should be repeated 2 weeks following the initial dose. They are generally well tolerated but can cause mild GI distress. Pyrantel pamoate has been associated with transitory elevation of liver enzymes, and its use should be avoided in patients with known liver disease.
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These agents approach 100% effectiveness in killing the worms, and symptoms usually subside within 48 hours. The patient is no longer infective once the deposited eggs are removed from the perianal area and clothing by cleaning. Clothing and bed linens should be laundered with detergent and hot water on the same day that oral treatment is given. It is important that all infected members of the household be treated simultaneously. Reinfestation is common and retreatment may be necessary.
Anal Fissure
An anal fissure is an acutely painful, elliptical, mucosal tear, often extending from the anal verge to the pectinate line (Fig. 98.2). It is most often located in the posterior midline of the anal canal, less commonly anteriorly. The inciting factor is usually trauma secondary to the passage of a large, hard stool or anal intercourse. The underlying pathophysiology is thought to be diminished anodermal blood supply abetted by increased anal sphincter tone (1). This leads to an unremitting cycle of pain, reluctance to have a bowel movement, and then further tearing once the bowel movement occurs. The problem is a common one, occurring with equal frequency in men and women (it is uncommon in children). Most patients, and many clinicians, attribute the pain to hemorrhoids, especially when streaking of the stool with blood occurs. It is important to remember that hemorrhoids, unless acutely thrombosed, are not a cause of anal pain.
As an anal fissure becomes chronic it looks more like an ulcer crater, with raised edges, scarring, and the exposed external sphincter at the base. These changes are usually associated with a prominent posterior skin tag known as a sentinel pile. This often resembles an external hemorrhoid, which helps further the confusion of these two diagnoses. Occasionally a chronic fissure, often in an atypical location, is caused by an inflammatory condition such as Crohn disease, syphilis, gonorrhea, or tuberculosis; iatrogenic scarring from local surgery or irradiation; or anal cancer.
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FIGURE 98.2. Important structures of the anal area. |
Diagnosis
An acute anal fissure manifests with the sudden onset of sharp rectal pain that occurs during defecation and is followed by a dull aching discomfort that may persist for several hours. There may be associated minimal bright red bleeding, usually noticed just on the toilet tissue. Itching and mucus discharge can be additional complaints. As noted, the pain is so severe that patients avoid having a bowel movement, further aggravating the situation.
On examination, when the buttocks are gently retracted, most anal fissures can be readily visualized, usually at the posterior margin of the anal verge. With more chronic fissures, a posterior sentinel pile may be appreciated. Once an anal fissure has been identified by inspection, usually no attempt should be made to perform a digital examination or anoscopy until treatment has alleviated the symptoms.
Treatment
Many patients with acute anal fissure can be made comfortable within a day or two, and cured within 3 weeks, by the use of conservative therapy. Stool softeners such as docusate or bulk laxatives such as psyllium preparations should be taken, and cathartics should be avoided. A high-fiber diet is recommended, along with the consumption of eight glasses of water daily.
Anal discomfort is relieved by the use of warm baths for 15 to 20 minutes two to three times per day and after each bowel movement (2). Local anesthetic creams (e.g., Nupercainal Cream, Anusol) or suppositories are also useful in providing temporary relief of symptoms.
Nitric oxide (NO) mediates relaxation of the internal anal sphincter. Therapeutic NO donors, such as nitroglycerin (glyceryl trinitrate), may be effective in the treatment of anal fissures. Most (3, 4, 5) but not all (6) studies have shown that the topical application of nitrates to the distal anal canal results in early symptomatic relief and in cure of up to 80% of both acute and chronic anal fissures after 6 weeks of treatment. Recurrence rates are unknown. The major side effect has been headache. The topical nitroglycerin preparations used in the reported studies (0.2%, twice daily) were much less concentrated than commercially available preparations (nitroglycerin ointment 2%, e.g., Nitro-Bid or Nitrol); a trial of this approach will
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require compounding by a pharmacist. Topical calcium channel blocker drugs have been reported to provide similar results, but are not available presently. Healing of anal fissures has been achieved also by the local injection of botulin toxin (7), which should be done only by a surgeon or a gastroenterologist. These approaches obviate operation for at least some chronic fissures (8).
Once a fissure becomes chronic or if 6 weeks of conservative therapy has failed, the next step is surgical referral for a lateral anal sphincterotomy. This procedure is usually done on an ambulatory basis, often under local anesthesia. Postoperative complications (e.g., bleeding, abscess formation) occur in fewer than 5% of cases. There may be early problems with some degree of anal incontinence in up to 8% of cases, but this is a long-term problem in fewer than 1% of patients and is usually confined to difficulty controlling flatus or liquid.
Pain relief is noted within 48 hours, and the fissure is usually healed in 2 to 3 weeks. The recurrence rate is 1% to 8%, and 96% of patients have a lasting excellent or satisfactory result. Transient postoperative incontinence is common.
Hemorrhoids
A precise characterization of hemorrhoidal disease is impossible because, despite centuries of medical speculation, neither the pathogenesis nor the cause has ever been elucidated. Hemorrhoids are not varicosities of the rectal venous plexus. There are no certain data to prove any of the popular theories of causation, such as a low-fiber diet, constipation, straining at stool, venous hypertension, obesity, certain occupations, genetic predisposition, and many others.
The currently popular theory associates hemorrhoids with distal displacement of the anal cushions. Anal cushions are part of the normal anatomy of the anal canal (Fig. 98.2). These cushions, which consist of hemorrhoidal venous and arterial plexuses, smooth muscle, and connective tissue, lie under the mucosa. The cushions apparently permit the passage of variable-sized stools without disruption of the rectal mucosa. Three cushions are usually found, in the right anterolateral, right posterolateral, and left lateral portions of the anal canal (Fig. 98.3), the common locations of internal hemorrhoids. This theory is consistent with an observed increase in hemorrhoidal disease in association with aging, groin hernias, and urogenital prolapse, all potentially caused by connective tissue degeneration.
Asymptomatic hemorrhoids are said to be present in half of the population older than 50 years of age, but this figure is suspect because the definition of the diagnosis is uncertain. The prevalence of self-reported hemorrhoidal complaints was 4.4% (equivalent to about 10 million people) in a national health survey, but patients tend to attribute all anorectal symptoms to hemorrhoids (9). The prevalence is the same in both sexes, but women develop hemorrhoids earlier, often in association with pregnancy, and men more commonly seek treatment (9).
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FIGURE 98.3. A: Common sites of hemorrhoids. B: Protrusion of anal cushions. |
Classification
Hemorrhoids are described as internal or external depending on whether they originate above or below the pectinate (dentate) line. External skin tags are commonly, and erroneously, referred to as hemorrhoids as well (Fig 98.2). Internal hemorrhoids are graded based on the degree of
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prolapse. First-degree hemorrhoids project into the anal canal but do not prolapse. Second-degree hemorrhoids prolapse with defecation and spontaneously reduce. At these stages the only symptom is painless, bright red bleeding. Third-degree hemorrhoids protrude with straining and often require manual reduction. In addition to hematochezia, these are associated with discomfort and sometimes a mucus discharge.Fourth-degree hemorrhoids are irreducibly prolapsed through the anus. They can cause severe discomfort, bleeding, and mucus discharge. At this stage strangulation can occur, constituting an exceedingly painful and potentially lethal emergency. Table 98.2 summarizes this classification of hemorrhoidal disease.
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TABLE 98.2 Classification of Hemorrhoids |
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Diagnosis
Symptoms
External hemorrhoids manifest with pain, often exquisite, as a result of thrombosis in the external venous plexus. There is a tender lump, and the pain is exacerbated by defecation.
Asymptomatic hemorrhoids noticed incidentally during an examination should not be considered a problem and should not be treated. The symptoms associated with internal hemorrhoids include.
Bleeding
Characteristically, the bleeding from hemorrhoids is mild, intermittent, and bright red. Occasionally it may drip into the commode or be sustained. Massive hemorrhage is rare. Rectal bleeding should never be attributed to hemorrhoids unless all other causes can be ruled out.
Prolapse
Prolapse of internal hemorrhoids produces the sensation of fullness in the anal canal, especially after defecation. This discomfort affects 80% of patients with symptomatic hemorrhoids, but it is not true pain.
Pain
The acute pain attributed to internal hemorrhoids usually is caused by a fissure (see earlier discussion). Pain caused by internal hemorrhoids indicates thrombosis or strangulation and if unresponsive to conservative management (see below), mandates referral to a surgeon. Thrombosis and strangulation occur when fourth-degree hemorrhoids are trapped by congestion and spasm of the anal canal. If ulceration ensues, localized infection may result, which rarely may spread to the portal venous plexus, leading to potentially lethal pylephlebitis.
Physical Examination
The patient is placed in the lateral decubitus or knee-chest position and the buttocks are gently separated. Skin tags are seen as soft, painless excrescences just beyond the anal verge. A thrombosed external hemorrhoid manifests in the anal canal as a firm, tender mass with a bluish discoloration. Internal hemorrhoids can sometimes be visualized as well, especially if the patient strains.
Digital rectal examination is performed principally to rule out other anal and distal rectal disease. Nonvisible internal hemorrhoids are rarely palpable.
Anoscopy is the definitive diagnostic procedure for internal hemorrhoids. It should be performed thoroughly and carefully, as described previously for the diagnosis of pruritus ani, with the use of a good side-viewing anoscope.
Endoscopy, using the flexible fiberoptic sigmoidoscope or colonoscope, should be performed for any patient older than 40 years of age with the recent onset of bleeding thought to be from internal hemorrhoids. This is a part of the assessment of GI bleeding, as discussed more fully in Chapter 45.
Differential Diagnosis
Several other problems may be confused with hemorrhoidal disease. Hypertrophied anal papillae occur along the pectinate (dentate) line (Fig. 98.2) in association with an anal fissure (see earlier discussion), with Crohn disease, or without obvious cause. These papillae usually are asymptomatic and require no therapy unless they have become particularly large, eroded, or infected or unless they bleed. Hypertrophied anal papillae often have the appearance of a fibrous polyp and are easily differentiated from hemorrhoids by their location and consistency.
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Rectal prolapse is identified by the circumferential abnormal downward displacement, or herniation, of rectal mucosa or of the full thickness of the rectal wall. When mild, it is commonly mistaken for hemorrhoidal disease and may respond to similar methods of treatment (see later discussion in this chapter on its specific diagnosis and treatment).
Protruding tumors such as rectal polyps, anal carcinoma, and even low-lying rectal carcinoma can be confused with hemorrhoids. If there is suspicion about the diagnosis, referral to a surgeon or gastroenterologist for evaluation and biopsy is appropriate.
Treatment
Without treatment, symptoms of hemorrhoids usually resolve spontaneously or in response to self-treatment within several days to several weeks, even when thrombosis is present. However, most patients develop recurrent symptoms, although the asymptomatic intervals may be long.
The aim of treatment (10) is to relieve symptoms, and only symptomatic hemorrhoids need treatment. Therapy does not necessarily reduce venous bulges, although often they do regress, most patients respond to conservative therapy.
Skin tags rarely need treatment. If they are sufficiently prominent to cause true discomfort, the patient can be referred for surgical excision.
Thrombosed external hemorrhoids are often acutely and severely painful and may require surgical referral for management. If the patient presents more than 72 hours after the onset of pain and as the acute symptom is subsiding, conservative measures usually resolve the problem. These consist of the approach used for conservative treatment of symptomatic internal hemorrhoids. In addition, topical analgesics such as Nupercainal or 5% lidocaine ointment should be applied. If prolonged sitting is necessary, an inflatable ring is helpful.
Symptomatic internal hemorrhoids, even fourth-degree ones, in the absence of severe symptoms, deserve a trial of conservative management. The first step is to avoid constipation and straining by giving of a bulk laxative and stool softeners. The patient should eat a high-fiber diet and drink at least eight glasses of water daily. Swelling and prolapse often respond to warm sitz baths taken twice daily and after each bowel movement.
Topical preparations may relieve discomfort, and putatively reduce swelling as well. Corticosteroid-containing preparations such as Anusol-HC and ProctoFoam-HC may be used initially, but their use should be discontinued after 2 to 3 weeks and the non–steroid-containing versions substituted. These preparations come as creams, foams, and suppositories. All three forms are beneficial, and their use depends on patient and clinician preference.
Surgical Management
Patients should be referred to a surgeon for evaluation whenever there is doubt about the diagnosis, if there is no response within 3 or 4 weeks to conservative therapy, if pain is severe (as may occur with thrombosis); or if there is evidence of strangulation, ulceration, perianal infection, or neoplasm. When uncomplicated hemorrhoids are recurrently symptomatic, the patient should be referred to a surgeon for definitive treatment.
The surgeon evaluates the patient, confirms the diagnosis, and then considers several therapeutic options that are not normally provided by general practitioners.
External Hemorrhoids
The usual indication for the surgical treatment of external hemorrhoids is painful acute thrombosis, especially within 48 to 72 hours after onset. The procedure is surgical excision under local anesthesia on an ambulatory basis. Incision and evacuation of the thrombus is a satisfactory maneuver for pain relief in the early stages of thrombosis. A definitive hemorrhoidectomy may be required later. Sometimes external skin tags are sufficiently troublesome to warrant excision. This can be done as an office procedure under local anesthesia.
Internal Hemorrhoids
Injection of Sclerosing Agents
Submucosal injection of a symptomatic hemorrhoid with several milliliters of a sclerosing solution causes fibrosis and retraction of the hemorrhoid. This procedure is excellent therapy for small bleeding internal hemorrhoids (first-or second-degree; Table 98.2); it is simple, requires no anesthesia, and can easily be performed in the office in a few minutes. After this procedure the patient usually requires no recovery period and can return to work immediately. There may be a period of several days when the patient experiences a sensation of anal fullness. This symptom is usually well tolerated or is easily controlled by the use of sitz baths three to four times a day and by mild analgesics such as acetaminophen.
The clinician performing this procedure must be experienced with its use. With the proper technique there are essentially no complications. If the solution is improperly injected, severe pain, necrosis, and rectal stenosis can occur. Injection of sclerosing agents usually provides temporary relief, but recurrence is common. The procedure may be repeated several times, but persistent recurrence should lead to the consideration of another mode of therapy. This approach is most useful for symptomatic first-degree hemorrhoids that are so small that there is insufficient tissue for rubber band ligation.
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Rubber Band Ligation
Rubber band ligation of hemorrhoids is a simple office procedure that can be utilized for internal hemorrhoids of all degrees except the fourth (Table 98.2) (11,12). The patient requires no special preparation, and no anesthesia is necessary. Using an anoscope and a special instrument, one or two rubber bands are applied near the base of the hemorrhoid and at least 0.5 cm above the pectinate line. No more than two hemorrhoids should be treated at a single session, but all of the hemorrhoids should be banded ultimately. Constriction by the rubber band results in ischemic necrosis of the hemorrhoid, which sloughs and is passed in the stool 5 to 10 days later, usually along with a small amount of blood. Complications are rare, but delayed massive bleeding and pelvic sepsis have occurred.
Usually, after rubber band ligation of hemorrhoids, the patient is not disabled and has only minimal discomfort characterized by a sensation of rectal fullness, a symptom that is usually well controlled by the use of sitz baths and a mild oral analgesic such as acetaminophen. Aspirin and nonsteroidal anti-inflammatory analgesics should not be used because of the risk of prolonged bleeding. If the discomfort is more severe, a mild relaxant such as diazepam (Valium) is helpful to relieve anal sphincter spasm. If the rubber band is improperly placed below the pectinate line, the patient will experience severe pain and the rubber band must be removed.
After rubber band ligation, the usual conservative measures for internal hemorrhoids should be practiced for 2 to 3 weeks until healing is complete. Further ligation is then performed if necessary. Banding provides good relief of hemorrhoidal disease approximately 70% to 90% of the time. Symptoms recur in 15% to 45% of patients after 18 months to 5 years.
Laser Therapy and Infrared Photocoagulation
Laser therapy and infrared photocoagulation are available as treatment modalities for first-, second-, and third-degree hemorrhoids (Table 98.2). Both require expensive equipment, and the carbon dioxide laser demands special expertise. Therefore neither modality is widely available.
Hemorrhoidectomy
Hemorrhoidectomy is indicated for large internal hemorrhoids after other forms of therapy have failed; for strangulated, ulcerated, or gangrenous third- or fourth-degree hemorrhoids; and when symptomatic hemorrhoids are present in conjunction with other benign anorectal conditions (e.g., fistulas, fissures) that require surgery (1). The procedure is usually done under general or regional anesthesia, although local anesthesia is possible. Patient preparation consists of a Fleet enema the morning prior to surgery. The purpose of the operation is to remove hemorrhoidal tissue and to appose the skin and mucous membrane. The operation has a deserved reputation for severe postoperative pain. Despite newer techniques and the most careful surgical approach the likelihood of postoperative discomfort remains. Postoperative discomfort is best controlled by sitz baths, stool softeners, oral analgesics, and a muscle relaxant such as diazepam (Valium). Topical nitroglycerin may also be beneficial. Postoperative complications are urinary retention and bleeding. The former can be averted by adequate control of pain and muscle spasm. The incidence of significant bleeding is 1% to 2%, and infection is rare. Late complications of incontinence or anal stenosis should occur in fewer than 1% of patients. The late recurrence rate is less than 5%.
Special Considerations
Because of an increased risk of complications associated with operative procedures in patients with severe congestive heart failure (CHF) or debilitating disease, the treatment of hemorrhoids in these patients should be as conservative as possible. Patients who have cirrhosis present a special risk because of the frequent association of hemostatic dysfunction. Hemorrhoidectomy should not be done in patients with Crohn disease and should be done in patients with ulcerative colitis only when they are in remission. Immunocompromised patients should not undergo anorectal surgery.
Hemorrhoids are common in pregnancy and are best managed conservatively. They often resolve spontaneously after delivery. Occasionally, development of strangulated hemorrhoids requires surgical intervention during the pregnancy.
Anorectal Abscesses and Anorectal Fistulas
Definition
An anorectal abscess is an abscess involving the perineum and perianal structures. Abscesses are classified by their anatomic location (Fig. 98.4). Low intramuscular or perianal abscesses are located in the subcutaneous tissue immediately surrounding the anus, which is the site of 40% to 50% of all anorectal abscesses. Ischiorectal abscesses are located in the ischiorectal fossa, a fat-filled space between the distal levator ani (external anal sphincter) and the ischial tuberosity, and account for 20% to 40% of anorectal abscesses. Intersphincteric, high intermuscular (postanal), and pelvirectal (supralevator) abscesses are far less common and account for approximately 10% of all abscesses. Anorectal abscesses are common, and the general physician should be familiar with their presentation, so if this problem is suspected, the patient can be promptly referred to a surgeon.
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FIGURE 98.4. Anatomic classification of common anorectal abscesses. |
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An anorectal fistula (fistula-in-ano) is a tract lined by granulation tissue that has an internal opening in the anal canal and an external opening in the perianal skin. The internal opening is usually located in one of the anal crypts at the upper end of the anal canal just above the pectinate line (Fig. 98.2).
Anorectal abscesses are more common in men. Most are associated with cryptoglandular infection. Occasionally, anorectal abscesses occur in association with other anal and perianal disorders (Table 98.3). Anal glands, thought to be diverticula of the anal canal mucosa, are located circumferentially around the anus at the level of the pectinate line. Many of these glands pass through the internal sphincter into the intersphincteric space. They normally drain into the anal crypts. Infection and abscess formation result when drainage of these glands is blocked. Bacterial cultures from the abscesses usually grow a mixed flora.
Most anorectal fistulas result from abscess formation in the anal glands and drainage through the perianal skin. Unless this is recognized and treated at the same time, the incidence of fistula formation after drainage of anorectal abscesses is about 50%. Some fistulas are not pyogenic in origin and are associated with inflammatory bowel disease or tuberculosis. Fistulas that do not originate in anal glands may result from diverticular disease, neoplastic disease, or trauma.
Diagnosis
History
Most commonly, a patient with an anorectal abscess describes throbbing perianal pain intensified by sitting, walking, coughing, or defecating (13). Systemic symptoms may be present and include malaise, chills, and fever. These symptoms are more common with ischiorectal than with perianal abscesses. If the abscess has spontaneously drained, the patient may complain of a mucopurulent or bloody discharge.
An uncomplicated anal fistula may create only minor complaints. The most common complaint is painful perianal swelling, but the most common symptom is discharge and soiling. The swelling is often intermittent, and the intensity of the discomfort is variable. Often the patient complains of a purulent anal discharge that, when it ceases, leads to recurrent painful swelling relieved by resumption of the discharge.
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TABLE 98.3 Conditions That May Be Complicated by Anorectal Abscess and Fistula-in-Ano |
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Physical Examination
A perianal abscess is easily recognized as a warm, tender, subcutaneous swelling located adjacent to the anus. With an ischiorectal abscess there is often only tenderness and induration detected by pressure on the skin overlying the ischiorectal fossa or the lateral wall of the anal canal during rectal examination. The high anorectal abscesses may present few or no findings on perianal inspection or even on rectal examination. However, these patients complain of severe rectal pain and pyrexia and exhibit a marked leukocytosis.
The diagnosis of an anorectal fistula is established by inspection and palpation of the perianal area and performance of a digital rectal examination. Often the external opening of the fistula in the perianal area can be seen. Digital examination of the rectum may enable identification of the indurated tract of the fistula as it passes to its internal opening at the pectinate line. Often the location of the internal opening is facilitated by anoscopy. Gentle passage of a probe may be attempted, but care must be taken not to create a false passage. Occasionally, accurate localization must await surgical exploration. When complex perineal infection is present, especially if no internal opening is found, the possibility of hydradenitis suppurativa must be considered (see Chapter 115).
Treatment
Even the suspicion of an anorectal abscess should lead to urgent referral to a surgeon for drainage (13). Temporizing treatment with oral antibiotics and sitz baths simply increases the risk of complications, such as systemic infection. An anorectal abscess may also be associated with a rapidly spreading necrotizing infection that destroys large areas of skin, subcutaneous tissue, and fascia. Patients with coincident diabetes mellitus are particularly vulnerable to complicated and extensive perirectal involvement. Finally, spontaneous rupture can occur either externally or internally, resulting in a complex fistula that is difficult to manage.
Preoperative broad-spectrum antibiotics need be given only to patients with anorectal abscesses who have valvular heart disease, diabetes, extensive inflammation or who are immunocompromised. Perianal abscesses may be drained under local anesthesia in the office or emergency room, but all other anorectal abscesses require regional or general anesthesia in the operating room. After drainage, the patient should receive oral analgesics and stool softeners and be instructed to begin sitz baths three times a day.
Most fistulas require fistulotomy (13). The internal and external openings must both be carefully identified and the tract converted into an open wound, which heals by secondary intention. Complex chronic fistulas can present difficult technical problems, and other surgical options may have to be considered. The wounds that result from any of these options commonly take 6 to 12 weeks to heal. The most serious postoperative complication is anal incontinence, which occurs in 3% to 7% of cases. The recurrence rate even for simple fistulas is approximately 5%, and it is higher for complex ones. Injection of fibrin glue to close the fistula appears to be effective in up to 60% of cases, especially for complex or recurrent fistulas (14).
Some patients with fistula-in-ano may be treated nonsurgically, either because of a lack of symptoms or because of complicating factors such as acquired immunodeficiency syndrome (AIDS). If there is a history of inflammatory bowel disease, a gastroenterologist should also be consulted.
Proctalgia Fugax
Occasionally, healthy young adults develop the sudden onset of severe rectal pain, variably intermittent and usually lasting from less than 30 minutes to 1 hour, known as proctalgia fugax. It often awakens the patient at night. It is significantly more common in women than in men, and it can occur after sexual intercourse. The pain is described usually as a spasm or a cramp. The problem is not associated with systemic illness or other GI diseases such as irritable bowel syndrome, and the cause is uncertain. There is
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often an association with psychiatric disturbances. Proctalgia fugax was long thought to result from spasm of a portion of the levator ani muscle, but it is now thought to be caused by paroxysmal hyperkinesis of the smooth muscle of the internal anal sphincter (15). Patients with proctalgia fugax may obtain relief by taking a hot sitz bath or applying pressure in the perianal area near the site of the discomfort. There are no proven pharmacologic remedies for this affliction. However, if the attacks are severe and frequent, some patients may find relief from the use of sublingual or cutaneous nitrates. There is also the possibility that nifedipine, a calcium channel blocker, decreases the frequency and intensity of attacks, and that the inhalation of albuterol shortens the duration of pain. The problem usually persists for many years but then disappears in later life.
Rectal Prolapse
Prolapse is a protrusion of the rectum through the anus. The protrusion may contain only mucosa (a mucosal prolapse), or it may contain all layers of the bowel wall (a full-thickness prolapse, or procidentia). There can also be an internal prolapse, or internal rectal intussusception, which produces typical symptoms without any external protrusion. This is often associated with the solitary rectal ulcer syndrome.
Prolapse is more prevalent in women (approximately 80% of the cases), with a peak incidence between the age of 60 and 80 years. In men the peak incidence occurs at about 40 years of age. The exact pathogenic mechanism in not known. Multiple factors are associated with this disease. Weakening of the fascial attachments of the rectum, attenuated muscles in the perirectal area and pelvic diaphragm, straining caused by chronic constipation, and even congenital fascial defects all lead to the development of rectal prolapse. Prolapse is often observed after severe chronic diarrhea. Mucosal prolapse also occurs commonly in children, usually before 2 years of age.
Diagnosis
History
Patients have variable symptoms, depending on the degree of prolapse. Initially, the protrusion occurs only with defecation, and the patient can easily reduce it manually. At this stage there may be no associated incontinence and the condition is sometimes mistaken for symptomatic internal hemorrhoids. The patient may complain of a sensation of displaced tissue at the time of a bowel movement, and there is often a feeling of incomplete evacuation. With progression of the problem, prolapse occurs with any straining and, eventually, simply with walking or even standing. At this stage incontinence is almost invariably a problem. With more profound prolapse, the patient may complain of tenesmus and also may develop a continuous mucous discharge. The prolapsed rectum may become excoriated and ulcerated, leading many patients to complain of bleeding. In association with an advanced degree of prolapse, the patient may also have urinary incontinence, and in women there may be associated uterine prolapse. Patients with increasing degrees of prolapse experience considerable embarrassment and consequently may avoid social contact.
Physical Examination
The clinician can best recognize rectal prolapse by inspecting the anus when the patient strains in a squatting position or sits on a commode. It is wise to anticipate incontinence with this maneuver. If the prolapse is full-thickness (procidentia), concentric folds of the rectal mucosa are seen; in mucosal prolapse, only radial folds are seen. Digital examination almost always reveals a patulous and relaxed anal sphincter that often admits two to four fingers. Palpation of the protruding tissue between the examiner's finger provides the sensation of only mucosa in mucosal prolapse or of a double layer of bowel wall in full-thickness prolapse. The rectal examination in patients with prolapse is usually associated with minimal or no discomfort.
Occasionally, prolapsed hemorrhoids are confused with rectal prolapse, but the absence of concentric or radial folds of mucosa and the prominent location of prolapsed hemorrhoids in the left lateral, right anterior, or right posterior edges of the anus suggest the proper diagnosis (Fig. 98.3). On occasion, a prolapse is associated with a rectal tumor. For that reason, a flexible fiberoptic sigmoidoscopic examination should be performed for any patient with rectal prolapse. Other diagnostic studies are not usually required, but a defecatory videoproctogram (available in only a few centers) is useful, especially for identifying an associated rectocele or internal prolapse.
Treatment
If the prolapse is small and limited to the mucosa, the patient may benefit from taking stool softeners and using a stimulant laxative suppository (see Chapter 46) to initiate defecation and thereby avoid straining at stool. If prolapse progresses despite this treatment, or if extensive mucosal prolapse is noted, it is appropriate to refer the patient to a surgeon. Redundant tissue may be treated by rubber band ligation, as for internal hemorrhoids. The procedure can usually be performed in the surgeon's office without anesthesia and is usually successful in preventing progressive degrees of rectal mucosal prolapse.
If procidentia (full-thickness prolapse) is present, only operative treatment is effective. Several procedures are available for the restoration of anal continence and
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reduction of prolapse. All of these operations require hospitalization, and most require general anesthesia. One important factor to consider before operation is whether incontinence will be improved. If a full preoperative assessment of anorectal function leads the gastroenterologist and surgeon to believe that incontinence is likely to persist, the alternative of providing the patient with a permanent diverting colostomy must be considered.
Both abdominal and perineal operations are available for the treatment of complete procidentia. The perineal approaches have usually been reserved for very elderly or high-risk patients because of perceived less-than-perfect results. However, published studies indicate that these operations may be satisfactory (16). Nonetheless, the most successful operative procedures for full-thickness rectal prolapse require an abdominal proctopexy, in which the rectum is secured to presacral fascia either by primary suture or by the use of synthetic mesh. This may or may not be accompanied by anterior resection of redundant sigmoid colon. Complications associated with the transabdominal surgical repair of prolapse are fecal impaction, presacral hemorrhage, stricture, infection, fistula formation, pelvic abscess, and intestinal obstruction. The complication rate is about 5%. However, fecal impaction can occur in up to 10% of patients after abdominal proctopexy. The complication rate for perineal repairs is low, and fecal impaction is rare. However, anastomotic leak with pelvic abscess, pelvic hematoma, and anastomotic stricture can occur. The operative mortality rate for abdominal operations is less than 3%, and for perineal procedures it is less than 1%.
Recurrence rates are in the range of 2% for the abdominal approaches and up to 30% for the perineal ones. However, of patients with preoperative fecal incontinence, 15% to 30% continue to have some degree of postoperative incontinence. This problem sometimes responds to biofeedback, which ordinarily is available only in specialized gastroenterology laboratories.
Sexually Transmitted Diseases and infectious proctitis
Anal and rectal problems may be caused by sexually transmitted diseases and infectious proctitis in persons who engage in anal sexual practices. Infection with human immunodeficiency virus (HIV) is also common in such situations (17). In addition to more widespread sexually transmitted diseases such as gonorrhea and syphilis, less common venereal infections may also be the cause of anal lesions.
Although anorectal symptoms may also be a result of nonspecific inflammation caused by trauma, rectal pain, tenesmus, and anal discharge should raise suspicion of infectious proctitis.
Diagnosis
Perianal lesions are seen in association with condylomata acuminata, herpes simplex virus type 2 (HSV-2), syphilis, chancroid, granuloma inguinale, and molluscum contagiosum. Perianal lesions in the form of abscesses, strictures, and fistulas are a late manifestation of lymphogranuloma venereum (LGV) and granuloma inguinale.
Condylomata acuminata are recognized as a typical collection of venereal warts, often extending within the anal canal. There is no specific diagnostic test. Condylomata acuminata associated with certain human papillomavirus (HPV) types are particularly prone to result in high-grade anal dysplasia, or even invasive squamous carcinoma. This is a particular risk for patients with HIV infection.
HSV-2 infection manifests initially as perianal or anal canal vesicles, but these have usually ruptured and coalesced into ulcerations before the patient is seen. Precise diagnosis requires either a direct fluorescent monoclonal antibody technique or culture of the virus. A perianal chancre may suggest the diagnosis of primary syphilis, and the typical verrucous excrescence of a condyloma latum, although rare, is pathognomonic of primary or secondary syphilis. The diagnosis must be confirmed by dark-field examination for spirochetes. Chancroid is associated with anorectal ulcers and abscesses, and the diagnosis is confirmed by culture. Granuloma inguinale is a chronic granuloma that eventually causes red, hard, perianal masses; biopsy is necessary for diagnosis. Molluscum contagiosum causes self-limited, painless, round, umbilicated lesions that can be confused with cutaneous cryptococcosis in patients with AIDS.
LGV, which is caused by specific immunotypes of Chlamydia, may present initially as an ulcer or inflammatory mass, and also causes proctitis. LGV may progress to abscess, fistula, and stricture formation and may require surgical management, occasionally necessitating a colostomy.
Proctitis is a manifestation of gonorrhea, Chlamydia infection, HSV-2, amebiasis, shigellosis, or occasionally rectal syphilis. All of these infections cause essentially similar and nonspecific symptoms of rectal discharge, pruritus, tenesmus, hematochezia, and constipation or diarrhea. Pain (odynophagia) is especially typical of HSV-2, Chlamydia infection, and chancroid and may also accompany syphilis. The proctitis of amebiasis has a rather typical appearance on sigmoidoscopy, but the symptoms are principally those of colitis, as is also true of shigellosis. Constitutional symptoms accompany HSV-2 infection and consist of urinary retention, impotence, and unexplained but disabling dysesthesias of the perineum, buttocks, and posterior thighs. Inguinal adenopathy is a common finding in conjunction with syphilis, LGV, or HSV-2 infection.
Diagnosis of all of these lesions requires anoscopy and flexible sigmoidoscopy. Gonorrhea causes a nonspecific
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mucosal inflammation with erythema, friability, and an exudate. Gram staining of the exudate reveals gram-negative intracellular diplococci, and a culture is confirmatory. Syphilitic proctitis is also nonspecific, and the diagnosis is made by dark-field examination of the exudate and serologic tests for syphilis (see Chapter 37). Chlamydia causes only a nonspecific proctitis, but LGV causes linear and aphthous ulcers extending from the rectum to the distal colon as well. Histologically as well as clinically, these findings resemble Crohn disease, and the diagnosis of LGV requires culture of the organism, which commonly necessitates tissue culture inoculation. Rising acute convalescent antichlamydial serum antibody titers are confirmatory but usually are not manifested for 1 month. Although the warts of condylomata acuminata usually appear in the perianal area, anoscopy is necessary to look for involvement of the anal canal. HSV-2 also causes predominantly perianal lesions, but anoscopy and sigmoidoscopy should be performed, because the anal canal can contain vesicular lesions or ulcers and the distal rectum may reveal proctitis with or without ulcers as well. Amebiasis often manifests with a characteristic sigmoidoscopic appearance of punched-out ulcers with a yellow base in addition to diffuse inflammation. The diagnosis is confirmed by stool examination for ova and parasites, as is that of giardiasis. A positive stool culture makes the diagnosis of shigellosis; proctitis with ulcerations are shown on proctoscopy.
Since these lesions may not be recognized unless an appropriate history is obtained, it is important that the clinician ask about sexual practices.
Information about the treatment of specific anorectal infections can be found in Chapters 35 (amebiasis and shigellosis), 37 (Sexually Transmitted Diseases), 102 (condyloma acuminata in women), and 102 (condyloma acuminata and molluscum contagiosum).
Specific References
For annotated General References and resources related to this chapter, visit http://www.hopkinsbayview.org/PAMreferences.