A 35-year-old man presents with a 3-week history of perianal pain. The patient describes excruciating pain and bleeding produced by defecation. These episodes of pain generally last for 15 to 20 minutes. Because of his pain, the patient has been unable to defecate over the past 3 days. He denies any fever, difficulty with urination, or previous episodes of pain. His past medical history is unremarkable. He does not take any medications. On physical examination, his temperature is 37.7°C (99.9°F), pulse rate 100 beats/min, and blood pressure 140/90 mm Hg. Examination of the perirectal region reveals an anal skin tag located in the posterior 12 o’clock position. There are no masses, erythema, or tenderness in the perianal or buttock region. During an attempted digital rectal examination, the patient had exquisite tenderness, resulting in an inadequate evaluation. The laboratory findings revealed a normal WBC count, normal hemoglobin and hematocrit values, and a platelet count within the normal range.
What is the most likely diagnosis?
What is the most likely mechanism for this condition?
What are your next steps?
ANSWERS TO CASE 43: Anorectal Disease
Summary: A 35-year-old man presents with severe anorectal pain associated with defecation. He has no fever. The examination is incomplete because of patient discomfort and reveals a perianal skin tag but no erythema, mass, or swelling.
• Most likely diagnosis: Anal fissure.
• Most likely mechanisms: Causes include trauma to the anal canal from the passage of large firm stool and regional ischemia of the mucosa related to a hypertonic internal sphincter.
• Next steps: At this juncture, a complete anal examination should be performed. Severe pain frequently prevents this examination from being completed, and most patients require sedation or a topical, regional, or general anesthetic.
ANALYSIS
Objectives
1. Learn the differential diagnosis for anorectal pain.
2. Learn the approach to diagnosis and treatment of common anorectal diseases.
Considerations
The case presented is classic for a patient with an anal fissure. Hemorrhoids, fistula-in-ano, and perirectal abscess are other commonly encountered anorectal complaints seen in clinical practice. These diagnoses are unlikely because hemorrhoids and fistulae are usually painless and an abscess would cause erythema and tenderness in the perianal and buttock region. To treat this patient, a thorough physical examination must be performed either under regional anesthesia or with sedation. An anal fissure may present as an acute or chronic problem. On physical examination, a tear is seen in the anoderm. The tear can also extend into the lining of the anal canal, often to the dentate line. It is produced by trauma caused by the passage of hard stool and the presence of elevated internal sphincter pressures (resting pressures). Anal fissures are commonly found in the posterior midline position and, if chronic, can be associated with a skin tag. The symptom most typical of anal fissures is intense pain accompanying defecation. Bleeding is also very common. Many patients with fissures have constipation, which can contribute to the problem but may develop as the patient refuses to defecate in an effort to avoid the pain. Nonoperative treatment should be attempted for patients with an acute anal fissure, including sitz baths, bulking agents, a stool softener, and topical nitroglycerine ointment. Nitroglycerine ointment acts as a vasodilator and improves blood flow to the ischemic posterior portion of the anal canal. When patients with chronic and recurrent fissures are encountered, local injection of botulinum toxin or operative therapy to reduce the resting sphincter tone (lateral internal sphincterotomy) may be indicated. The risk of incontinence with lateral internal sphincterotomy is as high as 35%. Thus, it should be used as a last resort.
APPROACH TO: Anorectal Complaints
DEFINITIONS
HEMORRHOIDS: Abnormal enlargement of the hemorrhoidal venous plexus caused by constipation or diarrhea, obesity, and increased intra-abdominal pressure. Internal hemorrhoids are located above the dentate line; external hemorrhoids are located below the dentate line. Internal hemorrhoids can be classified as follows:
Grade I—prominent hemorrhoids on inspection or on anoscopy
Grade II—hemorrhoids that prolapse but reduce spontaneously
Grade III—hemorrhoids that require manual reduction
Grade IV—nonreducible hemorrhoids
FISTULA-IN-ANO: Abnormal communication between the anal canal and the perineum. Fistulas are draining sinuses that represent the end result of perianal abscesses. Abscesses form when the crypts at the dentate line become obstructed. The crypts lead into anal glands, which then become infected and create abscesses. Most fistulas arise several weeks to months after the abscess is drained and track into different spaces and planes in the perianal region. Fistulas are named based on their relationship to the anal sphincter muscles: intersphincteric, between the internal and external sphincters; transsphincteric, across both the internal and external sphincters; suprasphincteric, above the sphincter complex, originating at the dentate line; and extrasphincteric, above the sphincter complex but originating in the rectum.
GOODSALL RULE: Used to find the internal opening of a fistula. Most fistulas located anteriorly to a transverse anal imaginary line, that is, an anterior hemicircumference of the anus, track straight directly to the dentate line. Fistulas in the posterior portion or hemicircumference track in a curved line toward the posterior midline or commissure of the anal canal.
SETON: A loop of plastic or silicone, commonly a vascular “vessel loop,” which is placed through a fistula when there is a significant amount of sphincter muscle involved. The seton spares the sphincter muscle and remains in place for weeks to months until the drainage resolves and the fistula closes.
CLINICAL APPROACH
Most patients with perianal, anal, or rectal disease self-medicate with over-the-counter products. They consult a physician only when the symptoms worsen or become complicated. It is therefore imperative to obtain a thorough, detailed history regarding symptom duration and prior treatments. An anorectal examination can be performed with the patient either in the left lateral decubitus position with knees flexed or in the prone jackknife position. The key is to provide the most privacy and comfort. The examination consists of a careful inspection of the anoderm followed by a digital examination and circumferential anoscopy with or without sedation. When indicated, rigid proctosigmoidoscopy or flexible sigmoidoscopy may provide additional information but generally requires additional preparations and a separate visit to the office or outpatient endoscopy suite. During inspection, one should look for lesions, rashes, discharge, or other defects. Digital palpation is performed to identify any masses, gauge sphincter tone, and establish the presence of bleeding (Table 43–1). Malignancy and inflammatory bowel disease should always be considered in the differential diagnosis when patients present with chronic or recurrent anorectal complaints. Biopsies should be strongly considered during the evaluation. Anoscopy is performed to visualize an anal tear and to inspect and evaluate palpable lesions and hemorrhoids. During anoscopy, visualization of the dentate line marks the division between the rectal and the anal mucosae. The lack of somatic innervation above the dentate line makes lesions above this area less painful.
Table 43–1 • EXAMINATION FINDINGS AND TREATMENT
Symptoms
Anal fissure: Severe anal pain with defection, bleeding, itching, and minimal drainage.
Hemorrhoids:
Grade I—asymptomatic or possible painless bleeding
Grade II—possible bleeding and pruritus
Grade III—prolapsing and bleeding
Grade IV—painful, nonreducible hemorrhoids
Perianal abscess: Painful, fluctuant perianal mass or ulcer associated with fever and/or purulent drainage.
Fistula-in-ano: Drainage of pus or mucus or minimal stool soilage on undergarments.
Treatment
Anal fissure: Sitz baths, stool softeners, suppositories, bulking agents, and nitroglycerin ointment. Chronic fissures can be treated with botulinum toxin injection or internal sphincterotomy (Table 43–2).
Table 43–2 • ANORECTAL DISEASES AND TREATMENT
Hemorrhoids:
Grade I—diet changes (increase bulk and fluid intake)
Grade II—diet changes, rubber band ligation, infrared coagulation
Grade III—rubber band ligation or hemorrhoidectomy
Grade IV—hemorrhoidectomy
Fistula-in-ano: Fistulotomy for superficial fistulae. Seton placement if more sphincter muscle is involved.
Abscess: Incision and drainage under local anesthetic if small, or under sedation if large.
COMPREHENSION QUESTIONS
43.1 A 44-year-old man is being evaluated for possible anal fissure. Which of the following findings suggest the diagnosis of an anal fissure?
A. Fever, a fluctuant mass, obesity, and diarrhea
B. Painless rectal bleeding, a purple anal mass, and an ulcer
C. Presence of a purulent sinus, erythema, and a fluctuant mass
D. A history of nighttime incontinence of gas and stool
E. Severe anal pain, a tear in the posterior anoderm, bleeding, and increased sphincter tone
43.2 The differential diagnosis for an anal fissure should include which of the following?
A. Rectocele
B. Condyloma
C. Rectal polyp
D. Crohn disease
E. Rectovaginal fistula
43.3 Which of the following is the most appropriate next step for a patient suspected of having anal fissure based on clinical history?
A. Obtain a barium enema, followed by a colonoscopy
B. Rectoanal examination under sedation, anoscopy, and proctoscopy
C. Anal biopsy, anoscopy in the office, and a barium enema
D. Rectoanal examination in the office without sedation, anal biopsy, and fissurectomy
E. Prescribe stool bulking agents
43.4 Which of the following is considered the most appropriate treatment for acute anal fissure?
A. Infrared coagulation, sitz baths, and oral antibiotics
B. Rubber band ligation, suppositories, and topical antibiotics
C. Increased dietary bulk, sitz baths, and nitroglycerin ointment
D. Infrared coagulation and fissurectomy
E. Excision of the fissure
ANSWERS
43.1 E. Severe anal pain associated with bowel movements, a tear in the posterior anoderm, bleeding, and increased sphincter tone are findings compatible with anal fissure.
43.2 D. Patients with anal fissure present with severe pain associated with bowel movements. Crohn disease, ulcerated hemorrhoid, and low anorectal malignancy should be included in the differential diagnoses when evaluating an anal fissure. Rectovaginal fistula patients present with the discharge of fecal material from the vagina.
43.3 B. Examination under anesthesia, anoscopy, and proctoscopy are appropriate steps in evaluating a patient clinically suspected of having an anal fissure. Once the diagnosis is confirmed, the treatment may range from nitroglycerine ointment, Botox injection, to lateral sphincterotomy based on the chronicity and severity of symptoms.
43.4 C. Conservative management of an anal fissure consists of increasing dietary bulk and using sitz baths, stool softeners, and nitroglycerin ointment.
CLINICAL PEARLS
Patients may be reluctant to volunteer information regarding bowel habits and duration of symptoms; therefore, it is important to be specific in questioning the patient during the interview.
Anorectal carcinoma may manifest as severe perianal pain and tenderness and must be considered part of the differential diagnosis.
Patients with anal fissure characteristically have severe anal pain, a tear in the posterior anoderm, bleeding, and increased sphincter tone.
A nonhealing anal fissure or a fissure located anywhere other than in the posterior area of the anus should alert the clinician to the possibility of Crohn disease or a malignancy.
A thrombosed external hemorrhoid not responding to medical therapy should be treated by excisional thrombectomy instead of incision and drainage.
REFERENCES
Corning C, Weiss EG. Anal fissure. In: Cameron JL, Cameron AM, eds. Current Surgical Therapy. 10th ed. Philadelphia, PA: Elsevier Saunders; 2011:230-233.
Nelson H, Cima RR. Anus. In: Townsend CM Jr, Beauchamp RD, Evers BM, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, PA: Elsevier Saunders; 2008:1433-1462.
Steele SR, Johnson EK, Armstrong DN. Anorectal abscess and fistula. In: Cameron JL, Cameron AM, eds. Current Surgical Therapy. 10th ed. Philadelphia, PA: Elsevier Saunders; 2011:233-240.