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Benign anorectal disease: An update on diagnosis and managementWhen a patient comes to your office with anorectal complaints, chances are that they have progressed to the point of extreme discomfort. This article will help you prepare for just such a visit.Jocelyne Gavin, PA-C; Madison Cuffy, MD; Farshad Abir, MD; Walter E. Longo, MDJocelyne Gavin works in GI surgery and Madison Cuffy is a resident in general surgery, both at Yale-New Haven Hospital, New Haven, Conn. Farshad Abir is a fellow in colorectal surgery at the Cleveland Clinic Florida, Weston. Walter Longo is the chief of GI surgery at Yale-New Haven Hospital. The authors have indicated no relationships to disclose relating to the content of this article.
For any anorectal problem, performing a complete history and physical examination is essential. Ask the patient about bleeding, pain, discharge, swelling, changes in bowel habits, pruritus, prolapse, fever, incontinence, prior sexual contacts, and dyspareunia. During the physical examination, pay special attention to temperature, body habitus, the abdomen, and the perineum. Digital rectal and bimanual examinations are mandatory. Also important are sphincter tone, presence of gross blood, and presence or absence of hemorrhoids. Anoscopy and proctoscopy are among the possible diagnostic tests. Anorectal anatomyUnderstanding anorectal anatomy is key to evaluating patients with benign anorectal disease. The anorectal area is the terminal portion of the GI tract. It includes the urogenital organs and the muscular, ligamentous, and connective tissue structures. As a functional unit, the anorectal area maintains fecal continence by acting as both a reservoir and an expulsion unit for feces. The rectum has both intraperitoneal and extraperitoneal segments (see Figure 1). The rectum begins at the confluence of the taeniae coli at the rectosigmoid junction. The National Cancer Institute defines the rectum as the last 12 cm above the anal verge.1
The anal canal is roughly 4 cm in length and extends from the anal verge to the proximal level of the levator-external anal sphincter complex.2 The sphincter mechanisms and the dentate line are of great importance when addressing the anal canal surgically. The dentate line is approximately 2 cm from the anal verge and is a place of transition from columnar epithelium (endoderm) to squamous epithelium (ectoderm). Between these layers is a transitional area called the cloacogenic zone. The dentate line is an important landmark because of differences in innervation, blood supply, and lymphatic drainage of the anal canal. The anal glands, of which there are typically four to eight, empty into the anal canal at the base of the anal columns. These extend through the full thickness of the mucosa and submucosa and even into the muscularis externa. They are branched, straight tubular glands with ducts lined with stratified columnar epithelium, and their function is mucus secretion. Fecal incontinenceFecal continence is the voluntary deferment of the passage of enteric contents to a socially acceptable time and place. Inadequacy of this voluntary control is symptomatic of some underlying pathology but is not diagnostic. Normal fecal continence requires a complex interaction among neurologic, myogenic, sensory, anatomic, and hormonal systems. Fecal incontinence is the manifestation of some disturbance of this complex system involving stool volume, consistency, and transit through the colon; mental function; rectal distensibility; anorectal perception; excretion; and retention. Evaluation Tools for evaluating anal incontinence include proctosigmoidoscopy, anorectal manometry, defecography, and anal endosonography. In anorectal manometry, a probe containing multiple pressure sensors and a balloon is placed in the rectum and anal canal to assess the resting and squeeze sphincter pressures.3 Anorectal manometry can provide useful information regarding anorectal function.3,4 Treatment Either surgical or nonsurgical treatment is used, depending on the severity and etiology of fecal incontinence. Nonsurgical management may include bowel management programs, pharmacologic agents, perineal exercises aimed at strengthening the pelvic floor muscles (Kegel exercises), and biofeedback. Bowel management programs attempt to normalize the patient’s bowel pattern using antidiarrheal medications or by hardening stools using fiber supple-ments. Medications such as loperamide or atropine/diphenoxylate may be helpful.5,6 Perineal strengthening exercises using biofeedback have improved sphincter strength. Surgical management involves interventions designed to correct abnormalities of the native sphincter and may include overlapping sphincteroplasty, dynamic graciloplasty, and sacral nerve stimulation. Another surgical intervention uses the gluteus muscles to create a new anal sphincter.7,8 Muscle transfer procedures have been improved by the addition of electrical stimulation (dynamic graciloplasty).9 An implantable pacemaker is also used for continuous muscle stimulation, reducing the need for constant patient diligence. The patient deactivates the pulse generator (pacemaker) in order to defecate. An alternative to sphincteroplasty may be an artificial sphincter, which is placed around the native sphincter via perianal tunnels. It remains inflated until the patient wishes to defecate and deactivates a manual pump implanted in the scrotum or labia majora. Anorectal fistulaA fistula is a chronic granulating tract connecting two epithelium-lined surfaces. Perianal fistulae, usually caused by perianal abscesses, communicate between the anal canal and the perianal skin of the perineum and cause considerable discomfort. Presentation The clinical presentation of anal fistulae varies widely and includes pain, swelling, fever, and bleeding. The practitioner can palpate an external opening, which is usually seen as an elevation of granulation tissue, often with purulent discharge. The number and locations of external openings and their relationships to the anal canal provide clues to the internal origin. An indurated cord beneath the skin is typically detected in the direction of the internal opening. It is interesting to note that hidradenitis suppurativa, pilonidal sinus, and Bartholin’s gland abscess or sinus may simulate the fistula appearance. The original Parks’ classification for fistula in ano defines four types of fistulae, which result from cryptoglandular infections: intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric.10 Characterization and evaluation Fistulae can be characterized according to the level at which they transgress the anal sphincters. The internal orifice of a low fistula begins below the puborectalis, while a rare high fistula involves an internal orifice originating above the puborectalis. High fistulae are often associated with Crohn’s disease, ulcerative colitis, or a foreign body. Fistulae may also result from probing excessively during fistulotomy surgery.11 In complex cases, such as fistulae resulting from Crohn’s disease, preoperative imaging is imperative. Endosonography with a linear probe is more accurate than MRI in detecting anorectal abscesses and much more accurate in evaluating complex fistulae. Confirming fistula complexity before planning sphincter-saving surgery avoids missing sepsis, which is known to increase recurrence.12 Surgical management Anal fistula treatment may require staged fistulotomy, endoanal advancement flap, prolonged drainage, muscle transfer procedure, or fecal diversion. Surgical treatment depends on the location of the fistula in relation to the anal sphincter. The goals of surgery are eradicating the fistula, preventing recurrent disease, and preserving sphincter function. Fibrin glue is also used to treat fistulae. Success rates vary, especially for long-term results.13 The advantage of fibrin adhesive is that it does not compromise continence; however, the chance of success may depend on the dimensions of the fistula. Anorectal abscess
Management Incision and drainage, packs, sitz baths, and drains are used to manage perianal and ischiorectal/ischioanal abscesses. The drainage site is near the central zone of erythema, tenderness, and fluctuance. The abscess should be incised close to the anal verge so that the fistula tract is short, and the incision should stay open long enough to allow drainage of the abscess. A supralevator abscess may arise in a variety of ways; the treatment is determined by its origin. The upward extension of an intersphincteric abscess is drained into the rectum, and the upward extension of an ischioanal abscess is drained through the ischioanal space onto the buttock.14 When pelvic pathology is the cause, this abscess may be drained into the rectum or via the abdominal wall or buttock. A horseshoe abscess occurs when pus infiltrates the ischioanal space via the deep postanal space. It is important to drain pus from both ischioanal fossae and the anal gland where the infection originated. Fissure in anoPainful linear ulcers in the anal canal extending from just below the dentate line to the margin of the anus characterize anal fissures. Young to middle-aged adults often present with these wounds; they may cause anal pain during and after defecation and bright red blood per rectum. The pathophysiology is not completely certain, but increased resting anal pressure from hypertonicity of the internal anal sphincter may be the cause.15 Anal fissures may be classified as primary and secondary depending on whether they result from trauma or occur as a manifestation of other diseases. The fissure can also be described as acute if it has been present for less than 30 days and as chronic if it has been present for more than 30 days. Treatment Most fissures respond to medical therapy. It is the first-line treatment and includes conservative measures such as a diet high in fiber and sitz baths. Some fissures may persist and become chronic, however.16 Other medical treatments include nitroglycerin ointment, calcium channel blockers, botulinum injection, and nitric oxide donors. Medical therapy is only marginally better than placebo for acute fissures and fissures in children. Surgical treatments include chemical sphincterotomy, lateral internal sphincterotomy, and flap anoplasty. Although lateral internal sphincterotomy has been shown to be an effective treatment for anal fissures, incontinence has been the major risk. A prospective study evaluating incontinence and quality of life after lateral internal sphincterotomy has shown that lateral internal sphincterotomy for treatment of chronic anal fissures only occasionally impairs continence and rarely diminishes the patient’s quality of life.17 HemorrhoidsAnal cushions at the tail end of the anal canal prevent the canal from tearing during defecation, aid in anal continence, provide anal sensation, and provide a complete seal of the anus in closure. The anal cushions appear in the right anterior, right posterior, and left lateral positions. Sometimes they become enlarged and cause symptoms, including bleeding, pain, and prolapse. The etiology of hemorrhoids is not known, although it is recognized that they can worsen in pregnancy. Constipation is not a risk factor; however, one study found that diarrhea might pose a risk.18
Treatment Hemorrhoid treatment includes medical management, sclerotherapy, rubber-band ligation (RBL), infrared coagulation (IRC), and surgical hemorrhoidectomy. Medical management includes a balanced diet, increased fluid intake, fiber supplementation, and topical therapy for local inflammation. Ointments that contain local anesthetics, mild astringents, or corticosteroids are available. Although the data are unclear about the use of corticosteroids, many patients report a beneficial effect.19 These agents may be used to provide short-term relief from discomfort, but no evidence supports their widespread use. Corticosteroids do not affect the underlying pathologic changes in the anal cushions. Nonexcisional therapy includes RBL. Anoscopy is performed to identify the origin of the hemorrhoid, which is grasped with forceps or a suction device. A band is then applied at its base. The strangulated hemorrhoid becomes necrotic and sloughs off, while the underlying tissue undergoes fixation by fibrotic wound healing. RBL cannot be performed on external hemorrhoids or grade IV internal hemorrhoids; it is only for grade II or III internal hemorrhoids. Sclerotherapy is an alternative to band ligation in grade I and II hemorrhoids. Injecting phenol in oil into the pedicle leads to tissue necrosis. Pelvic infection and impotence are the most rare and severe complications secondary to inaccurately sited injections.20 IRC is used to treat internal hemorrhoids.21 The apparatus produces infrared radiation from a 14-V wolfram-halogen projector bulb. A 1-second pulse is used, and two to six points are coagulated in each hemorrhoid. Treatment outcomes analyses In 1992, a meta-analysis of studies on IRC, RBL, and injection sclerotherapy showed that RBL was more effective over the long term than were the other two modalities. However, because of more pain and the reported rare incidence of pelvic cellulitis and death, the authors concluded that IRC was the treatment of choice for first-degree and second-degree hemorrhoids.22 IRC involved less pain but required repeated treatments. Sclerotherapy was less effective than either RBL or IRC. RBL is recommended as the initial mode of therapy for hemorrhoids of grades II to III. Patients who receive it are less likely to require further therapy than are those treated with the other modalities.23 In determining whether to use RBL or IRC, the clinician should ask patients whether they are willing to endure more discomfort with the initial therapy or prefer the treatment that causes less pain but may have to be repeated in the future. Surgical treatment Hemorrhoidectomy is recommended for symptomatic grade III hemorrhoids that do not respond to banding and for grade IV hemorrhoids. The procedure involves exposing the hemorrhoid with the anoscope and excising and ligating it. The addition of prophylactic metronidazole reduces pain and convalescence after day surgery and increases patient satisfaction.24 Surgical complications include urinary retention, secondary hemorrhage, anal stricture, infection, and impairment of continence. Strangulated hemorrhoids arise from prolapsed grade III or IV hemorrhoids that have become irreducible. The pain is severe, and urinary retention is common. If left untreated, strangulated hemorrhoids may progress to necrotizing perineal infection. Urgent hemorrhoidectomy is essential. This treatment has a higher early complication rate than elective surgery; however, septic complications are not increased.25 Hemorrhoids can also be surgically treated with a circular surgical stapler to remove a ring of anorectal tissue above the hemorrhoids. This technique lifts and flattens the hemorrhoids in the anal canal, the “face-lift” for hemorrhoids. The procedure for prolapsing hemorrhoids involves a stapled hemorrhoidectomy and is limited to internal hemorrhoidal disease and mucosal prolapse. Advantages include less pain, shorter hospitalization, and possibly improved postoperative function.26 ConclusionHaving read this article, the practitioner should now be knowledgeable about the diagnosis of and up-to-date therapy for fecal incontinence, anal abscesses, fistulae in ano, anal fissures, and hemorrhoids. REFERENCES
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Anorectal abscesses signify the acute process, whereas anal fistulae represent the chronic condition. Abscesses can be classified from the most common to the least common: perianal, ischioanal, intersphincteric, and supralevator (see Figure 2). The pericylindrical extension of an abscess is called a horseshoe. The physical examination findings in patients with an abscess include redness, pain, swelling, inguinal lymphadenopathy, and rectal tenderness.
Classification of hemorrhoids External hemorrhoids arise distal to the dentate line, are covered with anoderm, and rarely bleed, although they do swell and cause pain. Treatment is usually reserved for cases that involve acute thrombosis. Internal hemorrhoids arise above the dentate line and cause painless bleeding, prolapse, pruritus, hygienic disturbances, and anemia.