Anal Fissures

Definition, Etiology, PathogenesisTop

An anal fissure is defined as a longitudinal tear in the epithelial lining of the distal anal canal.

The exact cause of anal fissures is unknown. An initiating traumatic event, such as passage of a hard stool or trauma, causes a tear in the epithelial lining. High resting anal canal pressure (“hypertonic sphincter”) and reduced blood flow prevent healing and result in mucosal ischemia and fissure formation. Some risk factors that may contribute are diets lacking in fiber, previous anal surgery, childbirth, and laxative abuse.

The most common location is the posterior midline (up to 90% of cases). Anterior midline fissures are less frequent and are more common in women than in men. Nonetheless, in women posterior midline fissures remain the most common location. Lateral fissures are the least common and should prompt further investigation for an underlying etiology aside from nonhealing trauma.

Atypical fissures that are lateral, nonhealing, or nonsolitary should raise suspicion of diseases such as Crohn disease, tuberculosis, syphilis, HIV/AIDS, other dermatologic conditions (eg, psoriasis), leukemia, or primary anal malignancy.

Clinical Features and Natural HistoryTop

The main symptoms are sharp or burning pain on defecation that can last for hours after defecation and mild rectal bleeding (eg, bright red blood on toilet paper).

A physical examination by way of separation of the buttocks with thorough inspection of the perineum and gentle effacement of the anus is the most important step in diagnosing an anal fissure. A visible fibrotic tear in the posterior midline is the most common finding. A digital rectal examination is extremely painful for these patients and should only be performed if inspection is indeterminate. Chronic fissures (symptoms persisting for >6-8 weeks) also have associated features, such as an external sentinel anal tag and hypertrophied anal papilla internally.

DiagnosisTop

Diagnosis is usually made on the basis of history and physical examination, as well as endoscopic examination (ie, anoscopy and/or sigmoidoscopy).

Endoscopic examination may be delayed until resolution of pain following the initiation of treatment. Biopsies should be done if the fissure is atypical or nonhealing to exclude other diagnoses.

TreatmentTop

The goal of treatment is to achieve internal sphincter relaxation to allow healing while avoiding fecal incontinence. In general, acute anal fissures are managed conservatively (ie, lifestyle modifications), while more invasive treatments, including both medical and surgical treatment, are reserved for chronic anal fissures. Special attention should be paid to treatment of atypical fissures, such as in Crohn disease; expert opinion should be sought in cases that are thought to be due to underlying Crohn disease, infection, or malignancy.

1. Conservative management includes dietary modification for prevention of constipation, fiber supplementation, stool softeners if necessary, and warm sitz baths for pain control. These lifestyle interventions should typically be considered first-line treatment for acute anal fissures.Evidence 1Strong recommendation (benefits outweigh downsides; right action for all or almost all patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to the risk of bias. Davids JS, Hawkins AT, Bhama AR, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guideline for the Management of Anal Fissures. Dis Colon Rectum. 2023 Feb;66(2):190-199. doi: 10.1097/DCR.0000000000002664. PMID: 36321851.

2. Medical treatment involves the use of topical medications that produce reversible chemical sphincterotomy as an initial treatment for acute fissures.Evidence 2Strong recommendation (benefits outweigh downsides; right action for all or almost all patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to the marginal effect of intervention. Randomized controlled studies demonstrate that medical treatments have marginally better rates of healing than placebo (eg, 49% healing with nitroglycerin vs 36% with placebo). Davids JS, Hawkins AT, Bhama AR, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guideline for the Management of Anal Fissures. Dis Colon Rectum. 2023 Feb;66(2):190-199. doi: 10.1097/DCR.0000000000002664. PMID: 36321851. Nelson RL, Thomas K, Morgan J, Jones A. Non surgical therapy for anal fissure. Cochrane Database Syst Rev. 2012 Feb 15;(2):CD003431. doi: 10.1002/14651858.CD003431.pub3. Review. PMID: 22336789. Topical calcium channel blockers such as diltiazem (2%) or nifedipine ointment may be used. Anal fissures may also be treated with oral calcium channel blockers with similar efficacy but increased incidence of systemic effects. Topical nitroglycerin (0.2% or 0.4%) is another option; however, adverse effects are more common than with calcium channel blockers. The main complaint with the use of nitroglycerin is severe headaches. Medical treatment has better healing rates than placebo and there is no significant difference between calcium channel blockers and nitroglycerin, although calcium channel blockers have been noted to have a superior adverse effect profile.

3. Botulinum toxin injections directly into the internal sphincter can be performed in medically refractory chronic fissures.Evidence 3Strong recommendation (benefits outweigh downsides; right action for all or almost all patients). Moderate Quality of Evidence (moderate confidence that we know true effects of the intervention). Quality of Evidence lowered due to significant indirectness and heterogeneity (variability in administration dose, site, and frequency of injections in the studies as well as variability in healing rates reported in studies). Davids JS, Hawkins AT, Bhama AR, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guideline for the Management of Anal Fissures. Dis Colon Rectum. 2023 Feb;66(2):190-199. doi: 10.1097/DCR.0000000000002664. PMID: 36321851. Nelson RL, Thomas K, Morgan J, Jones A. Non surgical therapy for anal fissure. Cochrane Database Syst Rev. 2012 Feb 15;(2):CD003431. doi: 10.1002/14651858.CD003431.pub3. Review. PubMed PMID: 22336789. Healing rates are at least equivalent, if not greater, when compared with medical treatment in the initial management of chronic anal fissures. For refractory chronic anal fissures, healing rates are likely greater as compared with ongoing medical management. Some studies suggest decrease in pain scores with botulinum injections and fewer adverse events. The combined use of topical therapy and botulinum injections for chronic fissures can further improve healing rates.

4. Surgical treatment is reserved for severe, chronic, medically refractory fissures. In such situations lateral internal sphincterotomy is the treatment of choice with the highest healing rates, although the risk of incontinence exists. It is contraindicated in patients in whom incontinence develops following botulinum injections. Multiple randomized controlled trials have demonstrated superior efficacy of surgical treatment over topical therapy and botulinum injections or in patients with clinical evidence of incontinence at baseline.Evidence 4Strong recommendation (benefits outweigh downsides; right action for all or almost all patients). High Quality of Evidence (high confidence that we know true effects of the intervention). Davids JS, Hawkins AT, Bhama AR, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guideline for the Management of Anal Fissures. Dis Colon Rectum. 2023 Feb;66(2):190-199. doi: 10.1097/DCR.0000000000002664. PMID: 36321851. Nelson RL, Chattopadhyay A, Brooks W, Platt I, Paavana T, Earl S. Operative procedures for fissure in ano. Cochrane Database Syst Rev. 2011 Nov 9;(11):CD002199. doi: 10.1002/14651858.CD002199.pub4. Review. PMID: 22071803.