⭐⭐ ANAL FISSURE ⭐⭐

             ⭐⭐ ANAL FISSURE ⭐⭐

                  ( FISSURE - IN - ANO )

 EAS - External anal sphincter

 IAS - Internal anal sphincter

1) DEFINITION OF Anal fissure :- 

    Anal fissure is a small, superficial ulcer 

present along the longitudinal axis of lower part of anal canal.

It can be present in the midline, posteriorly,

or anteriorly. Anterior ulcers are more 

common in females.

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2) EXTERNAL ANAL SPHINCTER ANATOMY :-

 Three parts :-

   (a) Deep part - It encircles the upper end 

   of anal canal. There is no bony                     attachment.

   (b) Superficial part - It is attached 

   posteriorly to coccyx & anteriorly to

   mid perineal point in males & to vaginal

   sphincter in females.

   (c) Subcutaneous part - It encircles the 

   lower part of anal canal. There is no 

   bony attachment.

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3) INTERNAL ANAL SPHINCTER ANATOMY :-

It covers upper two third of anal canal. It 

is formed by thickening of circular muscles which are continued from the bowel above. Spasm & contraction of sphincter causes fissure & other anal infections.

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4) CAUSES OF ANAL FISSURE :-

Anal fissure is caused due to tearing of anal canal due to trauma & ulcer formation at that place. 

Following are the causes for trauma:-

   (a) Hard stools - Can cause sphincter to

   contract more forcefully leading to tear.

   (b) Trauma 

   (c) Diarrhoea - Repeated diarrhoea 

   causes damage to anal mucosa.

   (d) Sexually transmitted disease (STD)-

   eg. syphilis , gonorrhoea (inflammation 

   & damage)

   (e) Ischemia - Decrease in blood flow

   delays healing & hastens tissue damage.

   (f) Increased sphincter tone - It 

   decreases the blood supply to the anus

   & thus slows down the healing process.

   This can cause anal tear to develop.

   (g) TB - inflammation & ulcer formation.

   (h) Crohn's disease - inflammation & 

   ulcer formation.

   (i) Ulcerative Colitis - inflammation & 

   ulcer formation.

   (j) Anterior fissure is more common

   in females than males because there 

   is weak support for the anterior anal 

   canal due to the presence of vagina 

   anterior to anus.

   (k) haemorrhoidectomy - trauma during 

   surgical procedure.

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5) PATHOPHYSIOLOGY OF ANAL 

FISSURE :-

   (a) The above causes may cause tear to

   the anal mucosa leading to fissure.

   (b) Due to fissure, the internal sphincter 

   remains contracted & doesn't relax 

   because damage to anal mucosa leads 

   to hypersensitivity of receptors in the

   sphincter resulting in overreaction of the

   continence reflex & hence the spasm of

   sphincter occurs.

   (c) Spasm of sphincter leads to                     decreased blood flow which further 

   delays healing of the fissure which can 

   transform the acute fissure into chronic 

   fissure.

   (d) Pain occurs in fissure due to skin 

   damage, nerve damage & stimulation of

   nociceptors present in damaged tissues.

   This pain can be aggravated by ischemia

   & infection.

   The pain can also occur due to sphincter

   spasm because spasm leads to 

   ischemia (leading to drop in pH & 

   release of pain producing substances 

   like bradykinin, ATP, H+ )

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6) TYPES OF FISSURES :-

    (a) Acute anal fissure - tear with clean &

    sharp margins, no inflammation & 

    edema, severe pain , constipation & 

    spasm of sphincter.

    (b) Chronic anal fissure -

        # The margins are rolled out & 

        fibrosed.

       # Inferior part of fissure has skin tag

       which is edematous & guards the 

       fissure - sentinel pile. The upper part 

       shows hypertrophic papilla.

      # Chronic fissure is inflammed &

       edematous.

      # There is less pain.

      # It may undergo infection, abscess 

      formation, fibrosis or fistula formation.

      # Multiple fissures - present in 

      homosexuals, Inflammatory Bowel 

      disease.

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7) CLINICAL FEATURES OF ANAL 

FISSURE :-

   (a) Pain (explained in pathophysiology)

       # Severe in acute cases.

       # Less severe in chronic cases - nerve 

     endings are in the process of healing.

   (b) Bleeding, discharge - due to ruptured

   blood vessels or due to abscess 

   formation.

   (c) Constipation - due to pain & spasm.

   (d) In case of acute fissure, Per rectal 

   examination or proctoscopy cannot be

   done.(General anaesthesia is required)

   (e) In case of chronic fissure, Per rectal

   examination can be done & it can be felt

   as BUTTON LIKE DEPRESSION with

   enduration & sentinel pile.

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8) DIFFERENTIAL DIAGNOSIS :-

   (a) Anal carcinoma.

   (b) Anal chancre.

   (c) TB of anus.

   (d) Veneral diseases.

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9) TREATMENT OF ANAL FISSURE :-

   (a) General measures :

      # Drink plenty of water - so that stool

       doesn't become hard.

     # Fibre rich diet - soft stools.

     # Stool softener - Lactulose.

         Bulk forming agent - Psyllium.

     # Application of local anaesthetic -

     lignocaine, xylocaine.

    # Sitz bath - increases blood flow & 

    relaxes muscles.

    # Regular anal dilatation.

   (b) Acute fissures :-

      # Under general anaesthesia, dilatation

     of anal sphincter is done by manual

     stretching using two fingers of each 

     hand to relieve the spasm of 

     sphincter.

     # Bed rest

     # Application of local anaesthetic 

     (Xylocaine) or Nifedipine ointment 

    (causes relaxation of muscles - 

    Calcium Channel Blocker), 

    Laxatives.

   (c) Chronic fissure :-

     # Fissurectomy(excision of fissure)             with Sphincterotomy (cutting open

     of the sphincter & not complete

     excision) -  Sample is sent for ruling

     out Carcinoma, TB.

     # Botulinum toxin - It prevents the 

     release of Acetylcholine at 

     neuromuscular junction which causes

     relaxation of sphincter.

     # Nitroglycerin-  GTN - It decreases the 

     tone of sphincter muscle by release of

     nitrate which is converted into nitric

     oxide which is a smooth muscle 

     relaxant.

     # Diltiazem - Calcium Channel Blocker-

     Smooth muscle relaxation.

     # Regular anal dilatation.

     # Lateral anal sphincterotomy - Internal

     sphincter is divided away from the site

     of fissure by open or close method.

     CLOSE METHOD - Blade is inserted &

     moved upwards in the intersphincteric 

     groove. (between external & internal 

     anal sphincter) Then, blade is moved

     medially to cut the internal sphincter.

     OPEN METHOD - Incision outside the

     anal verge.(junction of perianal skin &

     anal epithelium) - dissection of 

     hypertrophied internal sphincter & it's

     division. Wound is left open.

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