ANAL FISTULA

By Asma Khan, MD

GENERAL DATA

A case of T.H 4yr old male currently residing in Cebu city. Patient was admitted on 11/10/2011 at CCMC for the first time.

Chief complaint: pus discharge at anal area

History of presenting illness:

3 years PTA mother noted that there is pus discharge at the anal opening, when patient tried to defecate with no other signs and symptoms no consult was done. No medications were given.

2 weeks PTA the mother noticed that the fistula was ruptured with pus and blood,thus sought consult at local hospital and no meds were given and no labs were done. Patient was diagnosed with fistula in ano and advised surgery.

A month PTA, patient mother decided to schedule the patient for operation at CCMC thus patient was admitted for surgery on 11/10/11.

ANTENATAL HISTORY Prenatal: The first prenatal checkup was at 12 weeks

AOG at the health center. Mother was given multivitamins and was given anti-tetanus vaccines. UTZ was done which showed no illness during pregnancy.

Natal: Delivered via NSD at home, delivered a live, male with no complications during and after delivery.

Postnatal: Patient was breast fed up to one year old with complete immunization.

Developmental milestones: 1.Smiling at 3months old. 2. Crawling at 7 months old. 3. Sitting with support at 9 months old. 4. Walking without support at 1 year.

PAST MEDICAL HISTORY

No previous hospitalizations, non-asthmatic. No food and drug allergies.

Family History:

There is a history of hypertension and diabetes on the maternal side. Paternal side has no medical illnesses.

Personal/social history: Patient was born in Caloocan city.

Patient is at the nursery level and Is very active and playful child as explained by the mother.

PHYSICAL EXAMINATION

General: Patient appeared conscious, coherent and not in respiratory distress.

V/S: HR:90 RR:20 Temperature: 36.8’cSkin: Warm to touch, Good turgorHEENT: Anicteric sclerae, pink palpable conjuctivae, (-)LADCHEST: clear breath sounds, equal chest expansionHEART: Distinct heart sounds, no murmurAbdomen: Soft, NABS, (-)TENDERNESS.EXTREMETIES: Strong pulse, CRT less then 2 secondsRECTAL: tight sphincter tone, an indurated track was palpable,

no occult blood. Prescence of PUSNeuro: With in normal limitsAdmitting impression: Fistula in ano

ANAL FISTULA

DEFINITION

Anal fistula is an abnormal communication between the anus and the perianal skin.,.

PATHOPHYSIOLOGY

Anal fistulae originate from the anal glands, which are located between the two layers of the anal sphincters and which drain into the anal canal. If the outlet of these glands becomes blocked, an abscess can form which can eventually point to the skin surface. The tract formed by this process is the fistula.

CAUSES

Anorectal abscess Trauma Crohn’s disease Carcinoma Radiation Tuberculosis

GOODSALL'S RULE

It is use as a guide in determining the location of the internal opening

With the patient in the lithotomy position:

Fistulas with external opening anteriorly connect to the internal opening by a short, radial tract.

Fistulas with an external opening posteriorly track in a curvilinear fashion to the posterior midline.

However exceptions to this often occurs when an anterior external opening is greaten than 3cm from the anal margin. Such fistulas usually track to the posterior midline

CLASSIFICATIONS OF ANAL FISTULAS Intersphincteric fistula : tracks via distal

internal sphincter & intersphincteric space to external opening near anal verge. Account for about 70% of all fistulae.

Transsphincteric fistulae are the result of ischiorectal abscesses & extends via both internal & external sphincters  Account for about 25% of all fistulae

Suprasphincteric fistulae originate in the intersphincteric plane & tracks up & around the entire external sphincter. Account for about 5% of all fistulae

Extrasphincteric fistulae originate in the rectal wall & tracks around both sphincters to exist laterally,usually in the ischiorectal fossa. Accounts for about only 1% of all fistulae

SYMPTOMS AND FINDINGS

Anal fistulae can present with many different symptoms:

Pain Discharge - either bloody

or purulent Pruritus ani- itching Systemic symptoms if abscess

becomes infected

DIAGNOSIS

Diagnosis is by examination, either in an outpatient setting or under anaesthesia

Possible findings: The opening of the fistula onto the skin may be seen. The area may be painful on examination. There may be redness. An area of induration may be felt - thickening due to chronic

infection. A discharge may be seen. It may be possible to explore the fistula using a fistula probe

(a narrow instrument) and in this way it may be possible to find both openings of the fistula.

TREATMENT

laying open technique (fistulotomy) is useful in the majority of fistulae repairs.  In this procedure, a probe is inserted through the fistula (through both openings), and the overlying skin, subcutaneous tissue, and sphincter muscle are divided, thereby opening the tract.  Curettage is used to remove granulation tissue in the tract base.  Care is taken to avoid cutting too large a portion of the sphincter (which could lead to incontinence).  The fistulotomy is allowed to close by secondary intention.

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TREATMENT Cutting seton - if the fistula is in a high position and it

passes through a significant portion of the sphincter muscle, a cutting seton may be used. This involves inserting a thin tube through the fistula tract and tying the ends together outside of the body.

The seton is tightened over time, gradually cutting through the sphincter muscle and healing as it goes. This option minimizes scarring but can cause incontinence in a small number of cases, mainly of flatus.

Once the fistula tract is in a low enough position it may be laid open to speed up the process, or the seton can remain in place until the fistula is completely cured.

Noncutting seton is a soft plastic drain placed in the fistula to maintain drainage. The fistula tract may subsequently be laid open with less risk of incontinence because scarring prevents retraction of the sphincter.

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