Anal Fissure is a split in the anoderm.
Ninety percent of anal fissures occur posteriorly and 10% occur anteriorly; location elsewhere should prompt exam under anesthesia and biopsy. Symptoms include tearing pain with defecation and severe anal spasm that lasts for hours afterward and blood (usually on the toilet paper).
Manometry and digital rectal examination demonstrate increased sphincter tone and muscular hypertrophy in the distal one third of the internal sphincter. An external skin tag or “sentinel pile” may also be present.
Differential diagnosis includes Crohn disease (fissure often in the lateral location), tuberculosis, anal cancer, abscess or fistula, cytomegalovirus, herpes simplex virus, chlamydia, and syphilis.
Ninety percent of patients heal with medical treatment that includes increased fiber, steroid suppositories, stool softeners, and sitz baths. Topical nifedipine ointment (0.2%) or nitroglycerin also has been shown to promote healing.
If surgery is required, lateral internal sphincterotomy is 90% successful. Recurrence and minor incontinence occur in fewer than 10% of patients.