INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

An anal fissure is a superficial linear tear in the anoderm most commonly caused by passage of a large, hard stool. This tear is distal to the dentate line. Anal fissures are among the most common anorectal disorders in the pediatric population; however, adults also are affected.

An anal fistula is an inflammatory tract between the anal canal and skin. The 4 categories of fistulas, based on the relationship of fistula to sphincter muscles, are intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric.

Fissures are defined as acute if present for less than 6 weeks, and they are defined as chronic if present for more than 6 weeks.

Pathophysiology

In anal fissures, anus distal to dentate line is involved. About 90% of anal fissures occur in the posterior midline where skeletal muscle fibers that circle the anus are weakest. The remaining 10% are found in the anterior midline.

Most anal fistulas originate in anal crypts, which become infected with abscess formation. When the abscess is opened or ruptures, a fistula is formed.

Sex

Anal fissures affect both sexes equally; however, an anterior fissure is more likely to develop in women (25%) than in men (8%).

• Anal fistulas are a complication of anorectal abscesses, which are more common in men than in women (male-to-female ratio of 2:1 to 3:1).
• Only 8% of anal fissures are anterior in men; 75-90% of fissures in women are posteriorly located.
• For reasons of intrinsic anatomy, rectovaginal fistulas are found only in women.

Age

Although anal fissures are the most common cause of rectal bleeding in infants, they are primarily seen in young adults.

• Eighty-seven percent of people with a chronic anal fissure are between the ages of 20 and 60 years old.
• Anal fissures in children may indicate sexual abuse.

CLINICAL

Section 3 of 11  

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• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

• Rectal pain, usually described as burning, cutting, or tearing
• Pain with bowel movements; spasm of the anus is very suspicious for an anal fissure.
• Bloody stools
• • Typically, bright-red blood appears on the surface of stools. Blood usually is not mixed into stool.
  • Occasionally, blood is found on toilet paper after wiping.
  • Patient may report no bleeding.
• Mucoid discharge
• Pruritus
• A patient with an anal fistula may complain of recurrent malodorous perianal drainage, pruritus, recurrent abscesses, fever, or perianal pain due to an occluded tract.
• • Pain occasionally resolves spontaneously with reopening of a tract or formation of a new outflow tract.
  • Pain occurs with sitting, moving, defecating, and even coughing.
  • Pain usually is throbbing in quality and is constant throughout the day.

Physical

• Start by optimizing patient placement; place the patient in the left lateral decubitus position with knees drawn up toward the chest.
• Examine the patient carefully to avoid infliction of further pain or sphincter spasm. Examination may be facilitated by application of a topical anesthetic, such as Lidocaine jelly, prior to digital rectal examination.
• Most fissures are visible externally when the patient bears down as if having a bowel movement.
• Note the depth of the fissure and its orientation to the midline, often described using clock orientation of the hour hand.
• Most tears are found in the posterior midline.
• Rectal examination is generally difficult to tolerate because of sphincter spasm and pain.
• Acute fissures are erythematous and bleed easily.
• With chronic fissures, classic fissure triad may be seen.
• • Deep ulcer
  • Sentinel pile, which forms when the base of the fissure becomes edematous and hypertrophic (a resolving sentinel pile can result in a permanent skin tag or may become associated with a fistulous tract)
  • Enlarged anal papillae
• Bidigital rectal examination in a patient with a fistula-in-ano may reveal an indurated tract or cord.
• • Fistula can be identified by small circles of granulation tissue, which exude pus when compressed if tissue is patent.
  • A fistulous tract that opens internally can be visualized with aid of an anoscope.
  • Inguinal lymph nodes may be enlarged and painful.
• In an acute fistulous abscess, cardinal signs of inflammation, rubor, dolor, calor, and tumor (eg, erythema, pain, increased temperature, edema) may be found.
• Examination of the anus reveals a linear tear in fissure-in-ano.

Causes

• Passage of hard stool
• Chronic diarrhea
• Ten percent of chronic anal fissures are caused by childbirth.
• Habitual use of cathartics
• Anal trauma (can occur with anal intercourse or a rectal examination using a speculum or digit)
• Causes of anal fistula include opened perianal or ischiorectal abscesses, which drain spontaneously through these fistulous tracts.
• Anal fissures can be observed in patients with syphilis and other sexually transmitted diseases, tuberculosis, leukemia, inflammatory bowel disease such as Crohn disease, previous anal surgery, HIV, and other conditions or diseases.
• • Incidence of anal fissures in patients with leukemia is approximately 24%.
  • Fistulas are also found in patients with inflammatory bowel disease, particularly Crohn disease. The incidence of fissures in Crohn disease is 30-50%. Perianal activity often parallels abdominal disease activity, but it may occasionally be the primary site of active disease. 
  • Anal fistulas also are associated with diverticulitis, foreign body reactions, actinomycosis, chlamydia, lymphogranuloma venereum (LGV), syphilis, tuberculosis, radiation exposure, and HIV.
  • Approximately 30% of patients with HIV develop anorectal abscesses and fistulas.

DIFFERENTIALS

Section 4 of 11  

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Other Problems to be Considered

Anal abrasion
Anal pruritus
Rectal or anal carcinoma

WORKUP

Section 5 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• Diagnosis of an anal fissure primarily is based on history and physical examination.
• Evaluation of an anal fistula involves at least a complete blood count (CBC) and a blood culture.
• • Look at number of white blood cells (WBCs) in anyone with a significant infection.
  • Depending on the condition of the patient, the possibility of bacteremia or sepsis must be considered. Blood cultures will better identify the offending organism, making it possible to treat infection more effectively.
• If syphilis or chlamydial infection is in the differential diagnosis, wound cultures may be necessary.

Imaging Studies

• If the extent of the underlying abscess is not known, a CT scan may be necessary to delineate its boundaries.

TREATMENT

Section 6 of 11  

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• Medication
• Follow-up
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Emergency Department Care

• Use the WASH regimen in treatment of anal fissures.
• • Warm water; shower or sitz bath after bowel movement
  • Analgesics
  • Stool softener
  • High-fiber diet
• Most uncomplicated fissures resolve in 2-4 weeks with supportive care. Chronic anal fissures frequently require surgical treatment.
• All surgical procedures involve stretching or cutting the internal sphincter. The most common surgical procedure is lateral internal sphincterotomy. Botulinum toxin has also been used with great success for treatment of anal fissures.
• Treatment of anal fistulae depends on (1) presentation of the patient, (2) evidence of sepsis or a large abscess, or (3) no worrisome findings on physical examination.
• • Administer intravenous antibiotics, antipyretic, and analgesic as needed.
  • If the patient is septic with hypotension, intravenous fluids or a pressor may be necessary.

Consultations

• Consultation usually is not necessary for anal fissures.
• An emergent surgical consultation may be necessary for fistulous abscess.
• Consult a gastroenterologist if inflammatory bowel disease is suspected.

MEDICATION

Section 7 of 11  

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For treatment of anal fissures, no medication other than stool softeners is necessary to facilitate less painful passage of stool during acute disease. Anal fissures can cause a vicious cycle in which the patient, in anticipation of pain associated with bowel movement, resists the urge to defecate, causing stools to become larger and harder; more pain with defecation results.

Antibiotics may be necessary for treatment of anal fistulas, especially if the patient presents with systemic symptoms.

Drug Category: Laxative/bulking agent

This agent facilitates easier passage of stools.

Drug Category: Muscle relaxant

This agent is used for relief of anal spasm.

Drug Category: Antibiotics

Therapy must cover both aerobic and anaerobic gram-negative organisms.

Drug Name	Ampicillin and sulbactam (Unasyn)
Description	Drug combination of beta-lactamase inhibitor with ampicillin. Interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms.
Adult Dose	1.5-3 g IV/IM q6-8h
Pediatric Dose	<3 months: Not established 3 months to 12 years: 100-200 mg/kg/d (150-300 mg Unasyn) IV divided q6h >12 years: Administer as in adults; not to exceed 4 g/d sulbactam or 8 g/d ampicillin
Contraindications	Documented hypersensitivity
Interactions	Probenecid and disulfiram elevate ampicillin levels; allopurinol decreases ampicillin effects and has additive effects on ampicillin rash; may decrease effects of oral contraceptives
Pregnancy	B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions	Adjust dose in renal failure; evaluate rash and differentiate from hypersensitivity reaction

Drug Name	Ticarcillin and clavulanate potassium (Timentin)
Description	Inhibits biosynthesis of cell wall mucopeptide and is effective during the stage of active growth; antipseudomonal penicillin plus a beta-lactamase inhibitor that provides coverage against most gram-positive, gram-negative, and anaerobic organisms.
Adult Dose	3.1 g IV q6h
Pediatric Dose	75 mg/kg IV q6h
Contraindications	Documented hypersensitivity; severe pneumonia, bacteremia, pericarditis, emphysema, meningitis, and purulent or septic arthritis should not be treated with oral penicillin during acute stage
Interactions	Tetracyclines may decrease effects of ticarcillin; high concentrations of ticarcillin may physically inactivate aminoglycosides if administered in same IV line; probenecid may increase penicillin levels; effects of this drug when administered concurrently with aminoglycosides are synergistic
Pregnancy	B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions	Perform CBC prior to initiation of therapy; if renal impairment is known or suspected, adjust dose and monitor blood levels to avoid possible neurotoxic reactions

FOLLOW-UP

Section 8 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Further Inpatient Care

• In the case of anal fissures, if the patient is having a great deal of pain, a topical anesthetic may be applied.
• Depending on the presence of systemic symptoms and the condition of the patient, the patient with an anal fistula may require continued intravenous antibiotics, fluids, pressors, and, possibly, surgery.
• Open lateral internal sphincterotomy is considered the treatment of choice for chronic anal fissure. It reduces the hypertonia of the internal anal sphincter, decreases pain, and allows the fissure to heal.

Further Outpatient Care

• For anal fissures, the WASH regimen is indicated.
• For anal fistulas, outpatient follow-up with a surgeon is indicated if consultation did not take place at the time of presentation.
• Botulinum toxin injection has been shown to be an effective alternative to surgery for the treatment of uncomplicated idiopathic anal fissure.
• Topical application of clove oil cream has demonstrated significant benefit in patients with chronic anal fissure.
• The application of topical 0.5% nifedipine ointment has been used as a chemical sphincterotomy agent. It has been shown to offer a significant healing rate for acute anal fissure and may prevent it from becoming a chronic fissure.

In/Out Patient Meds

• Psyllium may be prescribed for patients with anal fissures.
• For patients with anal fistulas, the following medications may be useful (if the patient is stable enough for discharge with outpatient follow-up):
• • Analgesics
  • Antipyretics
  • Antibiotics

Deterrence/Prevention

• Stress the importance of diet modification to soften stools.
• Patients should increase fruits, vegetables, and soluble and insoluble fibers in their diets and increase fluid intake.

Complications

• Constipation or fecal impaction may occur.
• The pain from an anal fissure can be so overwhelming that it discourages people from defecating.
• Acute fissures can become chronic.
• Sentinel pile can result.
• Permanent skin tag can result.
• Fistulas may form.
• The following surgical complications may occur:
• • Urinary retention
  • Bleeding
  • Abscess formation
  • Flatus and liquid incontinence
  • Recurrence of fissures
• Without treatment, chronically infected fistulas may cause systemic illness.
• Carcinoma has been reported in chronic untreated anorectal fistulas.

Prognosis

• Most uncomplicated fissures resolve in 2-4 weeks with supportive care.
• Fissures that heal with conservative treatment have a reoccurrence rate of up to 27%.
• Chronic anal fissures frequently require surgical treatment.
• Surgical treatment of anal fissures is associated with some degree of incontinence in 30% of patients.
• Prognosis for fistulas is excellent after surgery.

Patient Education

• Diet modification is indicated in the case of anal fissures.
• For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education articles Anal Abscess, Rectal Pain, and Rectal Bleeding.

MISCELLANEOUS

Section 9 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Failing to consider sexual abuse as a possible cause for anal fissure in a child
• Failing to refer the patient for further medical or surgical evaluation in the case of chronic anal fissure

MULTIMEDIA

Section 10 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Anal fistulas and fissures. This patient has a history of Crohn disease.
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Media type:  Photo

Media file 2:  Anal fistulas and fissures. This patient complained of constipation.
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Media type:  Photo

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

• Chung CC, Choi CL, Kwok SP, Leung KL, Lau WY, Li AK. Anal and perianal tuberculosis: a report of three cases in 10 years. J R Coll Surg Edinb. Jun 1997;42(3):189-90. [Medline].
• Farquharson M. Haemorrhoids, fissures and anal fistulae. Trop Doct. Oct 2002;32(4):196-201. [Medline].
• Garcia-Aguilar J, Belmonte C, Wong WD, Goldberg SM, Madoff RD. Anal fistula surgery. Factors associated with recurrence and incontinence. Dis Colon Rectum. Jul 1996;39(7):723-9. [Medline].
• Isbister WH, Prasad J. Fissure in ano. Aust N Z J Surg. Feb 1995;65(2):107-8. [Medline].
• Jonas and Scholefield. American Gastroenterology Association. 2004.
• Nordgren S, Fasth S, Hultén L. Anal fistulas in Crohn's disease: incidence and outcome of surgical treatment. Int J Colorectal Dis. Dec 1992;7(4):214-8. [Medline].
• North JH Jr, Weber TK, Rodriguez-Bigas MA, Meropol NJ, Petrelli NJ. The management of infectious and noninfectious anorectal complications in patients with leukemia. J Am Coll Surg. Oct 1996;183(4):322-8. [Medline].
• Oh C, Divino CM, Steinhagen RM. Anal fissure. 20-year experience. Dis Colon Rectum. Apr 1995;38(4):378-82. [Medline].

Article Last Updated: Sep 27, 2007