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 .
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.
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 .
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 . 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 .
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.
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 .
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 .
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 .
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 .
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 .