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KembaraXtra-Medicine – Anal Fissure
An anal fissure is a tear in the epithelial lining of the anal canal, extending from the dentate line to the anal verge. Acute anal fissures usually heal with conservative treatment within 6 weeks, while chronic fissures typically need a more aggressive approach and may require surgery. Synonyms include anorectal fissure and anal ulcer. The ICD-10CM codes are K60.0 (acute anal fissure), K60.1 (chronic anal fissure), and K60.2 (anal fissure, unspecified).
An estimated 235,000 new cases occur each year in the United States. Anal fissures can happen at any age but are more common in infants and middle-aged adults, and they occur more often in men than women. Women are more likely than men to have an anterior fissure (10% vs 1%, respectively).
Clinically, separating the buttocks typically reveals a tear in the posterior midline or less often the anterior midline. Acute fissures usually cause sharp burning or tearing pain with bowel movements and may produce bright-red blood on toilet paper, as a streak on stool, or in the toilet water; they look like a fresh laceration. Chronic fissures are more associated with perianal pruritus or irritation, less intense pain or no pain, and intermittent bleeding. They may show a sentinel tag at the caudal aspect, a hypertrophied anal papilla proximally, and raised edges that expose the horizontal fibers of the internal anal sphincter, reflecting chronic infection and fibrosis. Atypical fissures (acute or chronic) are more likely to appear off the midline, may extend proximal to the dentate line, may be unusually wide or deep, and may be multiple, recurring, or nonhealing; they can be associated with an edematous, tender perianal tag and are more often linked to an underlying systemic disease.
Most fissures start after passing a large, hard stool, but they can also result from frequent defecation and diarrhea. Infectious causes include bacterial infections such as tuberculosis, syphilis, gonorrhea, chancroid, and lymphogranuloma venereum, and viral infections such as herpes simplex virus, cytomegalovirus, and HIV. Other causes include inflammatory bowel disease (Crohn disease, ulcerative colitis), trauma (e.g., hemorrhoidectomy, foreign bodies, anal intercourse), and malignancy (carcinoma, lymphoma, Kaposi sarcoma).
Important differential diagnoses include proctalgia fugax, thrombosed hemorrhoid, carcinoma, and anal fistula. Evaluation may include a digital rectal examination performed only after fully lubricating the anus with 2% lidocaine jelly and waiting 5–10 minutes, plus anoscopy and proctosigmoidoscopy to exclude inflammatory or neoplastic disease. A biopsy is recommended if there is doubt about the cause, and studies should be done with adequate anesthesia. Colonoscopy is considered if IBD or malignancy is suspected, and a small-bowel series is occasionally obtained for similar reasons.
Nonpharmacologic management includes sitz baths, a high-fiber diet, and increased oral fluids. Acute treatment includes a bulk-forming agent (e.g., Metamucil) and/or a stool softener, and local anesthetic jelly (though it may worsen pruritus ani). Nitroglycerin ointment 0.4% can be used by applying 1 inch of ointment (≈1.5 mg nitroglycerin) intra-anally every 12 hours for up to 3 weeks; this product (Rectiv) can be expensive, and topical diltiazem (pharmacy-compounded) is also effective and usually cheaper. Suppositories are not recommended. If medical therapy fails after 2 months, surgery is considered.
For chronic fissures, medical therapy may still be offered because it is often better tolerated and avoids the risk of fecal incontinence. Options include topical glyceryl trinitrate, topical calcium channel blockers (e.g., topical nifedipine or topical 2% diltiazem cream), and botulinum toxin A injections into each side of the internal anal sphincter; botulinum toxin can heal chronic fissures in more than 90% of patients, although dosing and best injection site are not fully clear and it can be expensive. The standard, durable surgical treatment is lateral internal anal sphincterotomy, which has >90% long-term healing, is generally durable, and is noted not to compromise long-term fecal continence in the provided text—though it can lead to fecal incontinence and therefore requires careful patient selection.
Disposition is typically outpatient surgery when surgery is needed. Referral is recommended if the fissure does not improve with conservative measures in 4–6 weeks, if the patient prefers surgery for an acute fissure, or if the patient has a chronic fissure. A special consideration is that HIV-positive patients should be referred to clinicians experienced with the infectious and neoplastic conditions that can mimic anal ulcers in this population.
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