Anal Fissure


Figure 66-1 With the patient in prone jackknife position, a posterior acute anal fissure is visible once the buttocks are separated. (Courtesy Richard P. Billingham, MD, Seattle, Wash.).


What To Do:


image Most patients with an anal fissure cannot tolerate a digital rectal examination or anoscopy. Parenteral analgesia may be necessary prior to attempting any examination.


image To examine the patient, place him in the left lateral decubitus position with knees bent toward the chest. (Use proper draping to maintain the patient’s dignity and to minimize any embarrassment.) Good lighting is essential.


image Gentle retraction of the perianal skin usually allows one to visualize the fissure directly, even in patients with significant spasm.


image The mainstay of medical treatment for both acute and chronic anal fissures is the avoidance of hard stools. This can be accomplished with fiber supplementation and stool softeners. Advise the patient to take methylcellulose (Citrucel), 1 heaping tablespoon in 8 oz of water qd to tid, along with docusate sodium (Colace), 50 to 200 mg/day PO, divided in 1 to 4 doses (50, 100, 250 mg capsules). Lubricating glycerin suppositories used bid can also be helpful. All of these products may be purchased over the counter.


image To break the cycle of sphincter spasm and tearing of anal mucosa, and thereby promote subsequent healing of the fissure, medical therapy is often necessary. Prescribe topical nifedipine 0.2%, twice daily for 3 weeks, or diltiazem gel 2% (these prescriptions often need to be filled at a compounding pharmacy) with lidocaine HCL 2% gel, maximum dose 4.5 mg/kg, not to exceed 300 mg, to be applied every 12 hours for 8 weeks.


image Topical glyceryl trinitrate 0.2% or nitroglycerin ointment 0.2% (these prescriptions also may need to be filled at a compounding pharmacy) can be substituted for the topical diltiazem and nifedipine, but many patients are unable to tolerate the headaches that frequently occur. Avoid nitroglycerin therapy in patients taking Viagra or other erectile dysfunction medications.


image Instruct the patient to use warm, soothing sitz baths after each painful bowel movement.


image Prescribe analgesics if needed, but remember that narcotics are constipating.


image Botox injection into the sphincter may be considered if the above therapies fail; however, flatus or fecal incontinence is a potential side effect of this. Lateral sphincterotomy is usually successful when medical therapies fail, although complications may occur.


image Inform the patient that an acute superficial fissure will take about 4 to 6 weeks to heal. He or she should follow up if symptoms continue. At that point, endoscopy to assess for possible Crohn’s disease, and other diagnoses, should be considered.


What Not To Do:


image Do not assume that a lesion located outside the anteroposterior midline sagittal plane of the anus is an anal fissure. Lateral location, extension onto the anal verge or above the dentate line, and extension of the base of the ulcer through the internal sphincter are all atypical features. Other possibilities include ulcerative colitis, squamous cell carcinoma, leukemia, tuberculosis, syphilis, herpes, Crohn’s disease, sexually transmitted diseases, and trauma from instrumentation and anal intercourse. Appropriate follow-up should be arranged.


image Do not confuse a “sentinel pile” with a hemorrhoidal vein.


image Do not prescribe 0.2% nitroglycerin ointment for use in patients taking Viagra.


image Do not fail to refer an adult patient with rectal bleeding for endoscopy.



Discussion


Anal fissures probably begin by the tearing of the mucosa during defecation. Hard stools are most commonly implicated, but explosive liquid stools can produce the same results. This starts a vicious cycle of pain, causing spasm in the anal sphincter, which results in increased friction during defecation and leads to further tearing and pain.


Currently, ischemia is considered the most likely cause for development of an anal fissure. There is a paucity of anal blood vessels, especially in the posterior midline, and it is thought that anal spasm further reduces blood flow.


After a period of about 4 to 8 weeks, a fissure can be considered chronic. The cycle can be broken with analgesia, stool softening, lubrication, relaxation of spasm, or all four.


Although many acute anal fissures with a fresh skin tear heal spontaneously, some do not. With those that do not, secondary changes develop, with raised edges exposing the white, horizontally oriented fibers of the internal sphincter (chronic fissure). Botulinum toxin, which is a potent inhibitor of acetylcholine release from nerve endings, can be injected into the anal sphincter and can improve healing in patients with chronic fissures. One uncommon adverse effect associated with the drug is flatus incontinence. If the fissure is large, it may become ulcerated and infected, not heal spontaneously, and require surgical excision.


Pruritus ani has multiple causes, although most cases are idiopathic. Infections such as pinworms, Candida albicans, Tinea cruris, and erythrasma can cause anal itching. Mechanical trauma from overly vigorous cleansing of the perianal area may also cause pruritus. The latter may be aggravated by diarrhea and the presence of external or prolapsed hemorrhoids or multiple skin tags, which make cleansing more difficult. Another cause of pruritus ani is allergic or contact dermatitis from agents such as soaps, perfumes in toilet tissue, and feminine hygiene sprays, as well as spicy foods, tomatoes, citrus fruits and colas, coffee, and chocolate. Psoriasis, seborrheic dermatitis, atopic eczema, and lichen planus are additional dermatologic sources of itching. Other causes of pruritus ani include chronic anorectal disease, human immunodeficiency virus (HIV)-related infections, diabetes, cancer, and illnesses that produce hyperbilirubinemia. If a specific cause of anal pruritus can be determined, treat it accordingly. If the cause is obscure, the patient can be treated with hydrocortisone cream to reduce itching, scratching, and inflammation, followed by zinc oxide as a barrier cream.


In general, any medications such as antibiotics and laxatives should be discontinued, and the diet should be adjusted as necessary. A bulk-forming agent can be administered to allow for complete and predictable bowel evacuation, followed by bathing appropriately with warm water and little soap (to reduce chemical irritation). Using a hair dryer will provide gentle drying without further irritation. Moistened rectal wipes can be a reasonable alternative, but wipes containing chemicals such as perfumes, alcohol, or witch hazel should be avoided to reduce any effect of chemical contact dermatitis. Irritation from vigorous cleansing may actually worsen the itch. A systemic antipruritic agent, such as hydroxyzine (Vistaril), 25 mg orally 3 to 4 times daily, may be prescribed. Follow-up is required.


Proctalgia fugax is a unique entity found mostly in males, causing severe, brief, lancinating episodes of rectal pain lasting seconds to minutes. The pain is excruciating but is spontaneous and unrelated to defecation. The physical examination is completely normal, and treatment primarily consists of reassurance with an explanation of this benign disorder.

Aug 11, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Anal Fissure
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