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Anal Fissure

Fissure in Ano

Anal fissure is a linear crack or tear in the mucosa (anoderm) of the distal anal canal. It is often painful and involves the epithelium in the short term. In the long term, it involves the full thickness of the mucosa. They result from forceful dilatation of the anal canal most commonly during defecation.


Most patients with anal fissure will complain of pain on defecation. This pain is described as burning or tearing, worse during defecation and lasts for hours after bowel movement. This pain worsens with each bowel movement and makes the patients unwilling to have a bowel movement leading to worsening constipation and even more pain. Patients also complain of fresh blood on stool or on the toilet paper but it is not mixed with stool. There is no significant blood loss in anal fissure even though a few drops of blood may be seen dripping into the toilet water [4].

Most anal fissures occur in the posterior or anterior midline. Any fissure occurring outside the midline should raise suspicions of underlying medical conditions like infection, Crohn disease or cancer.

Recurrent Inflammation
  • BACKGROUND: Idiopathic chronic anal fissure is believed to be a consequence of a traumatic acute anodermal tear followed by recurrent inflammation and poor healing due to relative tissue ischaemia secondary to internal sphincter spasm.[ncbi.nlm.nih.gov]
Ankle Edema
  • Similarly, side effects like headache, palpitations, flushing, dizziness, colicky abdominal pain; ankle edema, reduced taste and smell, nausea and dyplopia have been reported 3] Local application of vasodilators: Nitric oxide is an important neurotransmitter[ncbi.nlm.nih.gov]
  • Bleeding Some ecchymosis may occur around the sphincterotomy site, but bleeding that requires therapy is extremely rare. Fistula formation Less than 1% of patients develop an anal fistula at the site of the sphincterotomy.[web.archive.org]
  • Pain and constipation were assessed prior to treatment and at 6 weeks after therapy using visual analogue scale (VAS) and Wexner constipation score. Adverse effects as headache and postural hypotension were also queried.[ncbi.nlm.nih.gov]
  • […] scented toilet paper Promptly treat all occurrences of constipation and diarrhea Avoid irritating the rectum Copyright 1995-2011 The Cleveland Clinic Foundation.[web.archive.org]
  • This pain worsens with each bowel movement and makes the patients unwilling to have a bowel movement leading to worsening constipation and even more pain.[symptoma.com]
Fecal Incontinence
  • CONCLUSIONS: The anal stretch appears to induce better resolution of chronic anal fissure with a very low risk of fecal incontinence.[ncbi.nlm.nih.gov]
Rectal Bleeding
  • Their clinical presentation consisted of constipation, rectal bleeding, anal pain, perianal itching, abdominal pain, irritability and rectal prolapse.[ncbi.nlm.nih.gov]
Rectal Pain
  • Rectal Pain Relief There are four common causes of rectal pain. Anal fissures, hemorrhoids, anal spasms, and Levator ani syndrome. Pain from conditions that cause rectal pain can be treated by condition.[emedicinehealth.com]
  • Using an anoscope may also help your doctor find other causes of anal or rectal pain such as hemorrhoids. In some cases of rectal pain, you may need an endoscopy for better evaluation of your symptoms.[healthline.com]
  • RECTAL PAIN: People often describe it as burning or tearing pain with a bowel movement. The pain may last for minutes or persist for hours after a bowel movement.[colonrectal.org]
Anal or Rectal Pain
  • Using an anoscope may also help your doctor find other causes of anal or rectal pain such as hemorrhoids. In some cases of rectal pain, you may need an endoscopy for better evaluation of your symptoms.[healthline.com]
  • For patient education resources, see the Digestive Disorders Center, as well as Anal Abscess, Rectal Pain, and Rectal Bleeding.[emedicine.com]
  • Similarly, side effects like headache, palpitations, flushing, dizziness, colicky abdominal pain; ankle edema, reduced taste and smell, nausea and dyplopia have been reported 3] Local application of vasodilators: Nitric oxide is an important neurotransmitter[ncbi.nlm.nih.gov]
  • , ANAL FISSURE, ANAL ULCER, Fissure, Anal, Anal fissure, unspecified, Anal ulcer unspecified, Anal Fissure, anal ulcer (diagnosis), anal fissure (diagnosis), anal ulcer, anal fissure, anal ulcer (___ cm), Fissure anal, Ulcer anal, Ulceration of anus,[fpnotebook.com]
  • Abstract Chronic anal fissure is a linear ulcer in the anal canal that has not cicatrized for more than 8-12 weeks of treatment. Most anal fissures are idiopathic and are located in the posterior midline.[ncbi.nlm.nih.gov]
  • If these small tears (and the occasionally associated superficial infection) are not promptly diagnosed and treated, they can cause severe anorectal pain during bowel movements and set in motion a cycle of stool negativism, constipation, and increasing[emedicine.com]
Dark Urine
  • When they occur, symptoms can include: Nausea, vomiting, and loss of appetite Unusual gain or loss of weight Yellow coloration of the skin and eyes (jaundice) Dark urine Bloody, black stools or unusually light-colored stools Vomiting of blood Abdominal[web.archive.org]
Sleep Disturbance
Flaccid Paralysis
  • The toxin exerts its effects on the acetylcholine releasing parasympathetic peripheral nerve endings as well as the ganglionic nerve endings, thereby leading to flaccid paralysis of the internal sphincter.[ncbi.nlm.nih.gov]


Usually, a diagnosis of anal fissure can be made with the combination of a gentle perineal examination and the history. Digital rectal exams are painful and are better deferred. If the fissure cannot be seen on examination, anoscopy should be done. Anoscopy is a painful procedure and application of topical lidocaine helps to alleviate the pain and improve tolerance. Patients with chronic fissures tend to tolerate pain better and proctosigmoidoscopy should be done [5].

Rhythmic Slowing
  • Mean and maximal resting anal pressure (MRAP), spontaneous rhythmic slow and ultraslow waves (USW) and relaxation induced by rectal distension were measured.[ncbi.nlm.nih.gov]


Treatment of anal fissure incorporates both medical and surgical components. Medical treatment involves the use of stool softeners and agents to make the stool more malleable and decrease the trauma associated with defecation. Sitz bath, in which the patient is advised to soak in a hot bath, will help to soothe the muscle spasm and decrease the pain associated with it and also help improve blood supply to the area and promote healing.

Infiltration of the internal sphincter with botulinum toxin creates a reversible paralysis which leads to better perfusion and a faster healing rate. Nitroglycerin ointment is also effective treatment although its side effect, headache, limits its use. Nifedipine ointment has a similar mechanism of action as nitroglycerin without the undesired side effect [6]. When conservative measures have failed, surgery is performed and the procedure of choice is lateral internal anal sphincterotomy.


It is not a life threatening condition so the mortality from anal fissure is essentially non-remarkable. It however has crippling morbidity. Less than 10% of patients will have a recurrence of anal fissure after sphincterotomy. This recurrence is may be attributed to an underlying disease or from an improperly/incompletely performed sphincterotomy. This necessitates frequent visits to the surgeon and possibly more surgical procedures.


The precise etiology of this condition is unknown although it is believed to be caused by trauma. The commonest source of trauma is from passage of particularly hard stools. The etiology is also associated with constipation, straining, inflammation, childbirth, anal cancer, and infections like syphilis, HIV, herpes and tuberculosis. Other factors that contribute to the formation of fissures are previous anorectal surgeries like hemorrhoidectomy or fistulotomy [2].


Anal fissure occurs more in younger children and middle aged adults with an incidence of as much as 1 in 350. It is occurs with identical frequency in both sexes. There is no documented racial predilection.

Sex distribution
Age distribution


Most cases of minor anal tears heal on their own within 4 to 6 weeks, but if there is an underlying abnormality in the internal sphincter, these injuries progress and result in acute and chronic fissures. In studies done on anal physiology, at least one abnormality has been found in the anal sphincter of patients with anal fissure. The most common abnormalities are the ones that lead to increased anal canal and sphincter resting pressure like hypertonicity and hypertrophy of the internal anal sphincter.

Another mechanism is due to poor perfusion of the posterior anal commissure. This rather mild blood supply is further compromised in patients with hypertrophied internal anal sphincters which makes the posterior midline of the anal canal ischemic. The pain experienced during each bowel movement due to stretching of the mucosa and grazing of this area with stool causes spasm which causes more pain and further compromises the blood supply to the area and leads to poor healing [3].


It is not entirely possible to prevent anal fissure but the risk can be reduced by taking steps to avoid constipation. Such measures include eating a high fiber diet, maintaining proper hydration preferably with water and regular exercise. Also, don’t ignore the urge to have a bowel movement, the longer the wait, the harder and dryer the stool gets [7].


Anal fissure is a fairly common condition and most of the cases resolve without any medical intervention. It is common in young infants and it often causes pain and blood in stool. If it doesn’t resolve, professional help should be sought [1].

Patient Information


Anal fissure is a tear in the delicate lining of the anal canal. It results from forceful stretching of the mucus lining of the anal canal and happens mostly during defecation.


It is mostly caused by passage of hard stool which results from constipation. Other causes could be from chronic illnesses, inflammation of the anal region and previous surgical procedures on the anal region.


The commonest symptom is pain on passing stools. Pain is often burning and tearing in nature and last for hours after passing stools. There could also be blood seen on the stool or on the toilet paper used for cleaning. There could also be drops of blood could be seen in the toilet water, this blood loss is not enough to cause any significant drop in blood levels [8].


Diagnosis is usually by careful examination of the anal canal, and this is usually enough to reach a definite conclusion. If the fissure is not seen, some imaging studies could be performed. These procedures are painful and are usually performed under anesthesia [9].


Treatment involves the use of medications to soften the stools. Also sitz baths help to relax the spasm and reduce pain. Some topical solutions are also used to reduce pain, improve blood supply and improve healing. Surgery may be done if conservative measures fail to produce desired effects [10].



  1. Grucela A, Salinas H, Khaitov S, et al. Prospective analysis of clinician accuracy in the diagnosis of benign anal pathology: comparison across specialties and years of experience. Dis Colon Rectum. Jan 2010;53(1):47-52.
  2. Schiano di Visconte M, Munegato G. Glyceryl trinitrate ointment (0.25%) and anal cryothermal dilators in the treatment of chronic anal fissures. J Gastrointest Surg. Jul 2009;13(7):1283-91.
  3. Samim M, Twigt B, Stoker L, Pronk A. Topical diltiazem cream versus botulinum toxin a for the treatment of chronic anal fissure: a double-blind randomized clinical trial. Ann Surg. Jan 2012;255(1):18-22.
  4. Abd Elhady HM, Othman IH, Hablus MA, et al. Long-term prospective randomised clinical and manometric comparison between surgical and chemical sphincterotomy for treatment of chronic anal fissure. S Afr J Surg. Nov 2009;47(4):112-4.
  5. Rather SA, Dar TI, Malik AA, et al. Subcutaneous internal lateral sphincterotomy (SILS) versus nitroglycerine ointment in anal fissure: A prospective study. Int J Surg. Feb 13 2010
  6. American Society of Colon and Rectal Surgeons, Standards Task Force. Practice Parameters for Ambulatory Anorectal Surgery. In: Diseases of the Colon & Rectum. Vol 34. Philadelphia, Pa: Lippincott Williams and Wilkins; 1991:. 285.
  7. Gibbons CP, Read NW. Anal hypertonia in fissures: cause or effect?. Br J Surg. Jun 1986;73(6):443-5.
  8. Klosterhalfen B, Vogel P, Rixen H, Mittermayer C. Topography of the inferior rectal artery: a possible cause of chronic, primary anal fissure. Dis Colon Rectum. Jan 1989;32(1):43-52. 
  9. Richard CS, Gregoire R, Plewes EA, et al. Internal sphincterotomy is superior to topical nitroglycerin in the treatment of chronic anal fissure: results of a randomized, controlled trial by the Canadian Colorectal Surgical Trials Group. Dis Colon Rectum. Aug 2000;43(8):1048-57; discussion 1057-8. 
  10. Schouten WR, Briel JW, Auwerda JJ, De Graaf EJ. Ischaemic nature of anal fissure. Br J Surg. Jan 1996;83(1):63-5.

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Last updated: 2019-07-11 22:23