Anal Fissures: A Real Pain

Patients with anal fissures frequently seek care for pain.

Anal fissures (also called fissure in ano) are a common affliction— second only to hemorrhoids in terms of patient complaints about the anus. However, researchers have been unable to estimate the true incidence of anal fissures.^1,2 Anal fissures are longitudinal tears that lie within the anal canal and cause a vicious cycle of inflammation, pain, and spasm. Because of the anus’s high concentration of pain fibers, patients describe anal fissure pain as “razor sharp” or “like broken glass.” To avoid pain, patients may avoid defecation and become constipated, which aggravates the condition.³ Anal fissures are most likely to occur around 40 years of age, with men and women equally affected. Anal fissures occur only rarely in patients older than 65 years.³

Overview

Anal fissures are most likely to occur at the anal wall’s relatively unsupported posterior midline. Anal fissures start as acute tears: they can be superficial like a paper cut or so deep they split the dermis down to the underlying sphincter muscle. Most acute fissures heal spontaneously within a few weeks, especially if constipation resolves. Tears that fail to heal within 6 weeks are considered chronic.⁴ Chronic anal fissures (CAFs) often cause structural changes in the anal area. Health care professionals recognize 4 common changes indicative of CAFs⁴:

• Exposure of anal sphincter muscle fibers
• Fibrous skin tags
• Hypertrophic anal papillae
• Hardened wound edges

Researchers identified CAFs’ possible causes, but its exact etiology remains unclear. Patients who have anal sphincter hypertonia or hypertrophia are more likely to develop CAF. Anal changes contribute to internal anal sphincter muscle spasm, impairing blood flow to the anal mucosa and healing. Women who have recently given birth, as well as patients with Crohn’s disease, are also at elevated risk.^1,5 Patients who experience one anal fissure are at increased risk of developing future episodes.^2,6

CAF patients most frequently seek care for pain,7 but they report other symptoms (Table^2,3,5). Fissures cause excruciating pain; to avoid exacerbating the pain, clinicians avoid performing a digital rectal exam or endoscopy. If the fissures require internal examination, clinicians administer anesthesia.^3,5

Stepping Up Care

Surgical lateral internal sphincterotomy (LIS)—the gold standard for CAF treatment— provides complete resolution in 94% to 100% of patients.^8-10 Because some degree of fecal incontinence or gas after surgery is common, most clinicians recommend conservative measures before advising patients to consider surgery.⁵ About one-half of patients heal using conservative measures.¹¹

To start, patients can modify their lifestyle and implement self-care measures. Because constipation is a serious concern, patients must increase dietary fiber and water consumption. Stool softeners are also important because patients must avoid straining during bowel movements. Additionally, patients should clean their anal regions gently.⁵

If the fissure does not respond, the next intervention is fiber supplementation to soften and bulk the stool. Any OTC fiber supplement can be used; patient preference is important. Short (<20 min) sitz baths in plain warm water can relax the sphincter and promote healing. Any form of soap or bubble bath should be avoided, as it may dry and irritate the area. Unscented creams and emollients can also relieve a simple, acute anal fissure, but are less likely to help CAF. Some clinicians prescribe hydrocortisone cream or lidocaine ointment.⁵

Pharmacologic Sphincterotomy

Since the early 1990s, prescribers have used pharmacologic sphincterotomy for CAFs that are unresponsive to conservative measures. This intervention emerged from research that demonstrated that nitric oxide (NO) is a critical neurotransmitter mediating internal anal sphincter relaxation, which suggested that the NO donor glyceryl trinitrate (GTN) could reduce resting pressure.^12-14 In addition, calcium channel blockers (CCBs) were found to relax the internal anal sphincter by blocking calcium influx into its smooth muscle cell cytoplasm.¹⁵ Nitrates and CCBs are generally applied topically.

Applied anally, nitroglycerin ointment— in strengths lower than those used for angina&mdash;twice daily for up to 3 weeks dilates blood vessels and increases blood flow. The primary side effect associated with nitroglycerin 0.4% ointment is headache within 30 minutes after administration. Headaches tend to decrease over time as patients develop tolerance. Patients can minimize headaches by remaining seated or lying down after application, avoiding exercise immediately afterward, and taking OTC analgesics (except aspirin) prophylactically. Regardless, up to 20% of patients discontinue nitroglycerin ointment due to headache.^16,17

Men should refrain from using nitroglycerin ointment within 24 hours of taking erectile dysfunction medications (eg, sildenafil, tadalafil, vardenafil) because the combination could significantly lower blood pressure. Patients receiving treatment for hypertension or headache are poor candidates for this approach.¹⁷

Calcium Channel Blockers: Find a Spatula

Nifedipine (0.2% to 0.5% gel) and diltiazem (2% cream) decrease mean anal resting pressure and improve fissure healing. ^18,19 Several studies suggest that topical CCBs are as effective as GTN and have fewer side effects. CCBs can cause mild headache in up to 25% of patients.^20-22 A single study comparing topical nifedipine with LIS found healing rates of 97% and 100%, respectively, at 8 weeks, with sustained results at 19 months.²³ These topicals need to be compounded, and pharmacists should note that this is an off-label use.²⁴

Another Botulinum Toxin Use

To treat CAF, clinicians have used botulinum toxin in doses of 5 to 100 U, with varying techniques. This is an offlabel use. Injecting a small dose of onabotulinumtoxinA into the anal sphincter paralyzes and relaxes the muscle for several months. A 180-patient meta-analysis including studies comparing botulinum toxin and nitroglycerin ointment found equal healing rates, but more side effects and headaches among nitroglycerin users.²³ Possible side effects include pain at the injection site or temporary, mild anal incontinence. Additionally, the cost associated with this agent can be high; it is available only in 50-, 100-, and 200-U vials, and use of a partial vial wastes the remainder.²⁵

Surgical Measures

LIS is usually done in an outpatient clinic. The surgeon cuts a small portion of the anal sphincter muscle to reduce spasm and pain and to promote healing. The procedure’s documented success is tarnished by risk of irreversible anal sphincter weakening. Between 3% and 16% of patients experience postsurgical decreased sphincter control of stool or gas,^8-10 so clinicians reserve LIS for patients in whom more conservative— and less costly&mdash;measures fail.

Endnote

Cost is a serious consideration for CAF patients and their insurers. A meta-analysis examined costs associated with rational progression of interventions (Online Figure). Treatment resulted in costs of $290 for 29 patients who used nitroglycerin alone, $3387 for patients who used nitroglycerin plus surgery, $20,580 for patients who used nitroglycerin and then botulinum, and $9025 for patients who used nitroglycerin plus botulinum plus surgery.⁶ This confirms that a stepwise approach to anal fissure²⁶ (Online Figure) is feasible, cost-effective, and highly successful.

Ms. Wick is a visiting professor at the University of Connecticut.

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