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View Full Version : Ano-Rectal Suppuration (Abscess - Fistula)(Etiology-Clinical picture-Invwstigation-Treatment)



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06-04-2008, 09:03 AM
q Aetiology:
Causative Organisms:
- Bacillus coli, Strept faecalis, staph, Cl. welchii, & Mixed infection.
Mode of infection:
- Direct spread from infected piles, anal fissure, colitis, or prostatitis.
- Blood spread from septic focus "rare".

Pathogenesis:
1- Infection usually begins at columns of Morgagni from which it pass through ducts of anal glands to inter-sphincteric space.
2- From the inter-sphincteric space it may take one of the following pathways:
a) Penetrate the int. sphincter and rest in submucosa submucous abscess 10%.
b) Pass downward to the peri-anal region peri-anal abscess 60%.
c) Pass upward to space between levator ani muscle and rectal wall
pelvi rectal abscess 5%.
d) Pass laterally to ischiorectal fossa ischiorectal abscess 25%.

3- If the infection pass in two directions from the intersphincteric space or from pelvi rectal space opening internally and externally will leading to
fistula formation which may take one of the following forms:
(I) Intersphincteric form (70%):
Pus pass directly to perianal space and submucous space then open to outside.
(II) Trans-sphincteric form (25%):
Pus pass to submucous space and between subcutaneous and superficial ext. sphincter to the subcutaneous space then open to outside.
(III) Supra sphincteric form (4%): Pus pass to intersphincteric space then ascend above the deep sphincter to pass outside.
(IV) Extra sphincteric form:
Pus pass to pelvirectal space and from it pass to the rectum above the anorectal ring and descend outside the ext. sph. to subcutaneous tissue then to outside.
Ÿ Previously the perianal fistulae were classified into:
(I) Anorectal abscesses
Cl. picture:
1- General:
Fever, headach, anorexia, malaise.
It is marked in ischiorectal and pelvirectal abscesses, minimal in peri-anal and submucous abscesses.
2- Local: Pain, tenderness & welling.
Sites of the swelling:
Perianal abscess around the anus.
Ischiorectal abscess ischiorectal fossa.
Submucous abscess anorectal junction.
Pelvirectal abscess ant. rectal wall above the pelvic diaphragm.
2- Hotness, redness, oedema in peri-anal and ischiorectal abscesses.
q Treatment:
1- Peri-anal abscess and ischiorectal abscess:
- Don't wait fluctuation i.e. Early drainage.
- Wide drainage must be done cruciate incision and excision of the edges of the wound.
- Under general anaesthesia.
2- Submucous abscess: drainage from inside by diathermy knife to prevent bleeding.
3- Pelvi rectal abscess: drainage is done through ischiorectal fossa with division of fibers of the levator ani muscle, and drainage tube is inserted.

F N.B We don't wait for fluctuation in:
1- Ano rectal abscess to avoid fistula formation.
2- Breast abscess to avoid destruction of breast tissue.
3- Pulp space infection gangrene of tip of finger.
4- Parotid abscess severe pain and fistula formation.

(II) Ano rectal fistula " Fistula in ano"
Definition:
Anal fistula is a track lined with granulation tissue connecting the skin to anal canal.
Aetiology:
Failure of healing of an ano-rectal abscess, due to:
1- Presence of lax arleolar and fatty tissue (poor healing and decrease resistance to infection).
2- Anal sphinctar hinders drainage.
3- Persistance of contamination through anal canal.

Pathology:
Track may be (straight - curved)
External opening: near anl orifice discharge pus.
Internal opening: in mucous membrane of rectum and anal canal if not present, the fistula is called blind external fistula.
Cl. picture:
Past history of ano-rectal abscess which drained either spontaneously or insuffecient surgically drained later on a sinus discharging pus.
When the opening is closed increase constitutional manifestations.
Signs:
1- By inspection:
Ÿ The shorter the distance between ext. opening and the anus the lower the internal opening.& the longer the distance the higher the int. opening.
* Good Sall's law:
If we imagine a transverse line bisecting the anus into ant. and post. halves.
a) If the ext. opening lies infront of that line, the int. opening will be opposite the ext. opening and the tract is short and at low level.
b) If the ext. opening was post. to that line, the int. opening open in the middle line by long curved tract.
2- P.R. Examination:
- To feel int. opening (Induration around it).
- To feel the tract. - To exclude carcinoma.
q Investigations:
1- Proctoscope : can exclude CA. and detect int. orifice.
2- Probing: under general anaesthesia during operation
3- Fistulography: injection of lipiodol into the tract may cause flaring of the infection. So, it is not recomended except in very difficult cases.
4- Biopsy: in recurent cases, if you suspect specific infection or malignancy.
qTreatment:
Fistulotomy or fistulectomy is the only method of cure
1- In all types below the deep ext. sphincter: one stage operation is done. The probing is done then an incision is done over the prope (Fistulotomy).
THEN, trimming of edges is done with the result that the cutaneous part of the wound is at least double the mucosal part. (Salmon's back-cut).
The triangular part left open, to heal by granulation tissue. (Fistulectomy).
2- If the internal orifice was above the deep Ext. sphincter, Two stage operation is done:
Ÿ The 1st stage is fistulectomy below the deep ext. sphincter with passing a silk suture around the deep ext. sphincter passing through the int. orifice
Ÿ 2-3 weeks later the inner remaining part is incised over the silk ligature.
Ÿ By this two stage operation we can avoid faecal incontinence as at the time we cut in the deep ext. sphincter, the surrounding adhesions prevent wound dehiscence.

3- In high anorectal fistula:
Ÿ Proximal colostomy and excision of the fistula tract.
Ÿ Closure of colostomy after complete healing of the wound.
SOURCE: DR. AYMAN SALEM'S BOOK
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