Colon and Small Bowel—Perirectal Abscess

Colon and Small Bowel—Perirectal Abscess

Concept

Constant pain in the rectal area. Arises from an infected anal gland. After drainage, about half will develop an anal fistula.

Way Question May be Asked?

“50 y/o male presents the ED with the complaint of hemor- rhoids. It started about 3 days ago, and the patient complains of severe pain, constant, and low grade fever and chills.”

How to Answer?

Targetel full H +P, as always

History

Constipation

Pain just with defecation (fissure) or constant (abscess) Bleeding

Topical therapy

History rectal complaints (incontinence, etc.) Family history IBD

Fever/Chills Prior rectal surgery HIV status

Trauma Abd Pain

Physical Exam

Examine abdomen

Rectal exam (pt in left lateral decub position) Anoscopy/Sigmoidoscopy not necessary May need to do exam under anesthesia

Look for malignancy, fistula, or other rectal pathology (careful for scenario switch)

Data

Labs (elevated WBC)

CT scan of pelvis (may predict level of the abscess)

Types of Abscesses

I Perianal—abscess in SQ tissue adjacent to the anal verge

II Ischiorectal—the infection travels through the sphincters into the ischiorectal space, may be mini- mal external signs, usually fluctuance a few cm from anal verge

III Intersphincteric—fluctuance/tenderness on rectal exam, abscess between internal and external sphincters

IV Horseshoe—bilateral ischiorectal spaces involved and deep posterior anal space

V Supralevator—from upward extension of intersphincteric or ischiorectal abscess, or from downward extension of pelvic process (diverticulitis, appendicitis, Crohn’s)

Surgical Treatment

Immediate incision and drainage

For I, II treatment is I + D under regional or general anesthesia

For III, treatment is drainage into the anal canal For IV, drainage of deep postanal space by dividing

overlying internal sphincter and lower portion of external sphincter and two counter incisions to drain ischiorectal extensions

For V, determine source first, if pelvic pathology, then external drainage of abscess, if rectal source, then drainage with mushroom catheter

Avoid fistulotomy at time of abscess drainage

Low threshold to return to OR if no improvement (especially in supralevator abscesses)

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May need diverting colostomy for severe/recurrent supralevator abscess or in pt with IBD

If scenario continues to management of fistula, surgery is always the answer:

Make sure to r/o associated GI diseases (IBD, HIV) Know pt’s baseline continence prior to going to OR Evaluate entire colon with BE or colonoscopy

Make need to inject H

O

or methylene blue to identify fistula openings

Fistulotomy unless fistula involves > 30% sphincter fibers or is anterior fistula in a female

Must assess the level at which the fistula traverses the sphincters

Treat intestinal disease in IBD and this will often accompany resolution of perianal disease or use Seton as a drain

Liberal use of the Seton (a nonabsorbable suture or rubber band placed through the tract that stimulates scar formation, gradually cuts through the sphincter mechanism as tightened over next several weeks, and minimizes post-op inconti- nence)

Goodsall’s Rule

when the external line lies anterior to the transverse anal line, the track runs in a direct radial line to the internal opening in the anal canal

when the external opening is posterior to the transverse anal line, the track curves backward to the posterior midline

Common Curveballs

Pt will have anal/rectal cancer Pt will develop post-op anal fistula Pt will have HIV or IBD

Pt will have postoperative incontinence

Pt will have history of portal HTN or be on blood thinners

Pt will have inflammatory bowel disease Pt will be pregnant

Won’t be able to perform rectal exam in office/ED ( → exam under anesthesia)

Pt will have severe abscess that doesn’t improve despite drainage (may need diverting colostomy)

Strikeouts

Not recognizing scenario and mistaking for throm- bosed hemorrhoid

Performing fistulotomy during first treatment of anal abscess

Admitting pt, placing on IV abx, and “waiting” for abscess to mature/reach the surface

Not recognizing associated GI diseases

Not ruling out pelvic pathology with supralevator abscess

Not making counter incisions with horseshoe abscess Not knowing Goodsall’s rule

Not knowing how/when to use a Seton

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