ANAL FISSURE

ANAL FISSURE - MichaelRousse, MD, MPH
BASICS
DESCRIPTION
Anal fissure is a benign ano-rectal disease characterized by a knife-like tearing sensation upon defecation. An anal fissure is a tear in the lining of the anal canal distal to the dentate line, most commonly in the posterior midline.
GENERAL PREVENTION
Avoid local trauma or stretch of the anal canal. Soften stool by maintaining adequate hydration and fiber intake.
EPIDEMIOLOGY
• Very common ano-rectal condition. Often confused with hemorrhoids by lay person and primary care physicians.
• Predominant age: Early adult. Elderly are spared this affliction due to lower resting pressure in the anal canal.
• Predominant sex: Affects men and women equally but women more likely to get anterior midline tears (25% vs 8%). Any tear off of the midline, suspect a secondary cause.
Incidence
Exact incidence is unknown. Patients often treat with OTC and home remedies and do not seek the advice of a physician.
Prevalence
As many as 20% of patients, the majority of whom did not seek the advice of a physician, have symptoms referable to the ano-rectum.
ALERT
Geriatric Considerations
Less common in the elderly because of lower resting anal sphincter tone
Pediatric Considerations
Not common in children, suspect abuse/trauma
RISK FACTORS
Constipation, passage of hard stool, high resting tone of internal anal sphincter, trauma, Crohn disease, HIV, syphilis, and TB
Pregnancy Considerations
Possible in pregnancy due to constipation and increased rectal pressure during and after pregnancy
Genetics
None known
PATHOPHYSIOLOGY
High resting pressure within the anal canal can lead to ischemia of the ano-dermal tissues; this increases the likelihood of splitting of the tissue with passage of stool. Thereafter, spasm of the internal anal sphincter results with or without passage of stool causing extreme, "knife-like," pain.
ETIOLOGY
Stretching and splitting of susceptible ano-dermal tissue
ASSOCIATED CONDITIONS
Crohn disease, TB, leukemia, and HIV


DIAGNOSIS
PRE HOSPITAL
ALERT
Special Considerations
Knife-like pain with defecation, associated blood streaked bowel movement
SIGNS AND SYMPTOMS
Patients present with severe rectal pain, often with and following defecation, pain may be continuous. They may describe bright red blood on stool or streaking the paper when wiping. Occasional itch or perianal irritation.
History
Pain and bleeding with defecation
Physical Exam
Gentle spreading of the buttocks will reveal a tear in the ano-dermal tissue, typically posterior midline, occasionally anterior midline, rarely eccentric to midline. Minimal swelling or bleeding. Hypertrophic papillae/sentinel tag seen in chronic fissure.
Diagnostic Procedures/Surgery
None, avoid anoscopy or endoscopy
• Some cases may require exam under anesthesia.
Pathological Findings
Tear in ano-derm, hypertrophic papillae, and sentinel tag.
DIFFERENTIAL DIAGNOSIS
• Thrombosed external hemorrhoidabsence of swollen mass
• Peri-rectal abscessfissure rather than a sinus
• SyphilisRare cause of recurrent fissures
TREATMENT
GENERAL MEASURES
Stool softeners, analgesics, and anxiolytics
Diet
High fiber, extra fluids
Activity
No restrictions
Nursing
No restrictions
SPECIAL THERAPY
Sitz baths
MEDICATION (DRUGS)
Directed at reducing muscle spasm within the internal anal sphincter, softening stool to facilitate atraumatic passage, and pain relief. (1)[C]
First Line
• Stool softeners, fiber supplementation
• Analgesics
• Nitratestopical nitroglycerin ointment 2% applied q.i.d.
Second Line
• Botulinum toxin4 mL injected into the internal sphincter muscle
• Calcium channel blockersoral or topical
SURGERY
• Reserved for failure of medical therapy, involves division of the internal sphincter muscle via various surgical approaches.
• Risk of fecal incontinence 45% in the short term, 6-8% in the long term. (2)[C]
FOLLOW-UP
DISPOSITION
Issues for Referral
Medical therapy usually tried for 90 days, surgery is then considered
PROGNOSIS
Topical therapy is less likely to be successful for chronic fissures, ~40% failure rate. (2)[C]
COMPLICATIONS
Fecal incontinence and incontinence to flatus are primarily associated with surgery.
PATIENT MONITORING
• Once healed, most patients should have a colonoscopy to further work-up rectal bleeding.
• If 50, sigmoidoscopy may be sufficient.
REFERENCES
1. MacLeod J. A Method of Proctology. New York: Harper  Row,
2. Breen E, Bleday R. Anal Fissure, Up To Date, 13.3. Waltham, 2006.
3. Schwartz S. Principles of Surgery, 7th ed. New York,McGraw-Hill;1999;1298-1299.