Anal fissures are linear ulcerations of the distal anal canal anoderm (Figure 6). Fissures often result from difficult, traumatic bowel movements. Patients with chronic anal fissures frequently have elevated resting anal pressures; the increased pressure leads to decreased anodermal blood flow and local ischemia—especially at the posterior midline, where there is a paucity of vessels.
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Symptoms and physical findings. Symptoms may include burning or aching pain that occurs during—and especially after—bowel movements; bleeding; spasm; and fecal soiling. Patients may fear having a bowel movement. Digital evaluation reveals increased anal sphincter tone.
The majority of fissures appear as anodermal defects located in the posterior midline, although 10% of women and 1% of men have anterior fissures. An associated "sentinel pile" or sentinel skin tag can often be seen at the distal or caudal extent of the fissure (see Figure 6); this represents fibrosis and excess granulation from the ulceration. These skin tags are frequently mistaken for hemorrhoids; however, a midline location—especially of an isolated skin tag—helps rule out symptomatic hemorrhoids. Fissures that are unusual in appearance or location may be associated with Crohn disease, malignancy, tuberculosis, syphilis, Cytomegalovirus infection, or HIV infection.
Management. Medical therapies for anal fissures include avoidance of straining or heavy lifting, warm baths, psyllium(Drug information on psyllium) or other bulking agents, topical anesthetics/analgesics, chemical sphincterotomy (by nitroglycerin 0.2% ointment3 or diltiazem 2% gel,4 applied with a gloved finger 2 or 3 times daily for 6 weeks), and injection with botulinum toxin. Anal fissures often resolve within 6 weeks of initiation of treatment; however, recalcitrant fissures may require surgical intervention (either lateral internal sphincterotomy or fissurectomy and sphincterotomy with anoplasty).5
