Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

all patients

1st line – surgical drainage of abscess

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ACUTE
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all patients
1st line – 

surgical drainage of abscess

Drainage of the abscess should be accomplished without undue delay because of the potential for the abscess to spread into a necrotizing, soft-tissue infection with life-threatening sepsis.[3][4]

Perianal abscesses can frequently be drained in the office or emergency department using local anesthesia and drained externally. Perirectal abscesses should be drained in the operating room where optimal anesthesia can be achieved.

Intersphincteric and supralevator abscesses frequently require general anesthesia to allow for an adequate anal examination to make a diagnosis and drain the abscess. These abscesses should be drained internally into the anal canal and rectum, respectively.[10][16]

Some evidence suggests that immunosuppressed patients with neutropenia and lack of fluctuance on examination may be treated initially with antibiotics alone, with surgical drainage considered after multidisciplinary consultation.[4][25]

Plus – postoperative care

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ACUTE
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all patients
Plus – 

postoperative care

Treatment recommended for ALL patients in selected patient group

Patients should begin baths with comfortably warm water 2 or 3 times daily postoperatively to clean the wound until healed. Warm water baths should also be used for cleansing after bowel movements.

Absorbent dressings can be used to prevent staining of underclothes if there is drainage.

A diet containing 25 g to 30 g of dietary fiber/day and 60 to 80 ounces/day of fluid should be considered to prevent hard stools.

Consider – fistulotomy

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ACUTE
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all patients
Consider – 

fistulotomy

Treatment recommended for SOME patients in selected patient group

If examination at the time of surgical drainage reveals an associated anal fistula (usually with perianal or perirectal abscesses; rarely with intersphincteric or supralevator abscesses) consideration can be given to managing the fistula at the same time.[28][30][31][32]

Anal fistulae that are superficial, involving less than 30% of the sphincter mechanism can be managed by fistulotomy. An alternative would be the placement of a loose, plastic seton to act as a drain.[27][29] The seton reduces the risk of recurrent anorectal abscess and will allow for sphincter-preserving management of the fistula after the acute infection has resolved and the fistula tract has matured. If the anal fistula involves more than 30% of the sphincter mechanism, fistulotomy is not an option but consideration can still be given to placement of a seton to prevent recurrent anorectal abscess.[23]

If the abscess is being drained outside the operating room or under local anesthesia, it may not be possible to perform an adequate anal examination or place a seton. In this circumstance, there is a risk of recurrent anorectal abscess.

Plus – broad-spectrum antibiotics with anaerobic and gram-negative coverage

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ACUTE
|
all patients
|
with associated cellulitis, immunocompromise, signs of systemic infection, diabetes, or history of cardiac valvular disease
Plus – 

broad-spectrum antibiotics with anaerobic and gram-negative coverage

Treatment recommended for ALL patients in selected patient group

Broad-spectrum antibiotics with anaerobic and gram-negative coverage should be started preoperatively and be discontinued within 24 hours of surgery or after cellulitis has resolved.

There is no standardized antibiotic regime in the literature.

In general, some combination of an intravenous broad-spectrum penicillin (e.g., ampicillin/sulbactam) or a second- or third-generation cephalosporin (e.g., cefoxitin or cefotetan) is combined with either clindamycin, ciprofloxacin, or metronidazole.

For patients who present with a necrotizing soft-tissue infection, broad-spectrum antibiotics as described above are mandatory. In addition, a more aggressive surgical approach is warranted with complete debridement of infected soft tissues. Multiple trips to the operating room are frequently needed before the necrotizing process is brought under control. Given the lethality of necrotizing soft-tissue infections, care in an intensive care unit is necessary.[24]

Primary options

ampicillin/sulbactam: 1 g orally/intravenously every 6 hours

More

or

cefoxitin: 1 g intravenously every 8 hours

or

cefotetan: 1-2 g intravenously every 12 hours

-- AND --

metronidazole: 500 mg orally/intravenously every 6 hours

or

ciprofloxacin: 200-400 mg intravenously every 12 hours; 500 mg orally every 12 hours

or

clindamycin: 600 mg orally/intravenously every 8 hours

Consider – aminoglycosides

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ACUTE
|
all patients
|
with associated cellulitis, immunocompromise, signs of systemic infection, diabetes, or history of cardiac valvular disease
Consider – 

aminoglycosides

Treatment recommended for SOME patients in selected patient group

There is no clinical evidence to support triple antibiotic coverage. While some authors also recommend adding an aminoglycoside (gentamicin or tobramycin) to the regimen, potential complications should be considered.

Treatment is for 24 hours or until the cellulitis has resolved.

Aminoglycosides are known to cause nephro- and ototoxicity. If used for more than 24 hours, serum levels need to be monitored.

Primary options

gentamicin: 80 mg intravenously every 8 hours for 24 hours or until cellulitis has resolved

OR

tobramycin: 80 mg intravenously every 8 hours for 24 hours or until cellulitis has resolved

Plus – re-examination under anesthesia/exclusion of rare microbiologic cause

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ACUTE
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all patients
|
unresponsive to initial treatment
Plus – 

re-examination under anesthesia/exclusion of rare microbiologic cause

Treatment recommended for ALL patients in selected patient group

Adequate drainage of the abscess should result in a prompt improvement of symptoms. If not, re-examination under anesthesia is recommended to ensure complete drainage of the abscess.

Inadequate drainage of the abscess occurs most commonly in patients with horseshoe abscesses when the postanal or ischiorectal component of the abscess is more prominent and is drained, but the other abscess components are not recognized and treated.[17]

For patients who develop a recurrent anorectal abscess or whose wound from the initial drainage fails to heal, examination by a general or colorectal surgeon is indicated to exclude an anal fistula as the cause of these problems.[27][36]

For patients with recurrent anorectal abscess and risk factors such as HIV, immunosuppression, or patients from a developing region, consideration may also be given to some of the rare causes of anorectal abscess, such as tuberculosis or actinomycosis. Specific microbiologic and culture techniques may be needed to identify these conditions.[21][20]

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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