http://surgerybook.net/

of disease in patients with severe and complicated CDI. The indications for surgical management of CDI

patients are not clearly defined, but severe disease, worsening clinical condition despite appropriate

treatment, and peritonitis or shock states are all potential indications. The two surgical procedures

indicated for CDI treatment include (1) total abdominal colectomy (for peritonitis, colonic perforation,

ischemia, necrosis, toxic megacolon with impending perforation, septic shock with organ failure) and

(2) diverting loop ileostomy and intraoperative colonic lavage for toxin reduction while preserving the

colon (Fig. 8-3). This new treatment strategy resulted in reduced mortality compared with the historical

population who had undergone total abdominal colectomy (19% vs. 50%), and preservation of the colon

was achieved in 93% of patients.34 No randomized studies have been published to date comparing these

two options.

Pancreatitis

A new classification of acute pancreatitis has been implemented and is based on local disease (whether

pancreatic necrosis is present or not, whether it is sterile or infected) and systemic determinants

(whether organ failure is present or not, whether it is transient or persistent) of severity (Table 8-9).

Early management requires goal-directed fluid resuscitation (with avoidance of over-resuscitation and

abdominal compartment syndrome), assessment of severity of pancreatitis, diagnostic CT imaging to

assess for necrotizing pancreatitis, consideration of endoscopic retrograde cholangiopancreatography

(ERCP) for biliary pancreatitis, and early enteral nutrition support. Antibiotic prophylaxis for severe

acute or necrotizing pancreatitis is not recommended.35

Figure 8-3. Diverting loop ileostomy with antegrade colonic irrigation for CDI. Before surgery is started:

1. Place the patient in lithotomy position with easy access to rectum

2. Place a fluid collection bag (commonly used by urology) under the patient’s rectum for drainage collection

3. Place a rectal drainage tube (large Malecot catheter, large foley catheter, #9 or #10 endotracheal tube, or other large catheter)

4. Have 8 L of warmed polyethylene glycol 3350/electrolyte solution (GoLytely; Braintree Laboratories) available in OR for

intraoperative colonic irrigation, and dulcolax suppository

Intraoperatively:

1. Ensure that the colon is viable and without perforation

2. Create a loop ileostomy (laparoscopic or open)

3. Place a 24-French Malecot catheter into the efferent limb of the ileostomy and advance into the right colon through the

ileocecal valve. Secure to skin with sutures.

4. Infuse 8 L of warmed polyethylene glycol 3350/electrolyte solution (GoLytely; Braintree Laboratories) into the 24-French

Malecot catheter via the efferent limb of the ileostomy

5. Once colonic lavage completed, perform rectal examination to empty rectum, place dulcolax suppository in rectum to

encourage colonic emptying

6. Instill antegrade colonic enema with vancomycin (500 mg in 500 mL) via ileostomy efferent limb, continue postoperatively

(Adapted from Neal MD, Alverdy JC, Hall DE, et al. Diverting loop ileostomy and colonic lavage. An alternative to total abdominal

colectomy for the treatment of severe, complicated clostridium difficile-associated disease. Ann Surg 2011;254(3):423–429.)

Table 8-9 New International Classification of Acute Pancreatitis: Determinants of

Severity of Acute Pancreatitis by the 2011 World Congress of the

International Association of Pancreatology

246

http://surgerybook.net/

Necrotizing pancreatitis is high risk for progression to necrotizing infected pancreatitis. Therapeutic

antibiotics are required for treatment of documented infected pancreatic necrosis. Causative pathogens

include gram-negative microbes and an increase in gram-positive organisms has been reported.36

Therefore broad-spectrum IV antimicrobials are recommended.

10 The initial treatment of infected pancreatic necrosis is percutaneous catheter or endoscopic

(transgastric/transduodenal) drainage with a second drain placement as required. The “step-up”

approach consisted of percutaneous drainage followed, if necessary, by minimally invasive

retroperitoneal necrosectomy. The minimally invasive step-up approach, as compared with open

necrosectomy, reduced the rate of the primary composite endpoint (12% vs. 50%, including major

complications [new-onset multiple organ failure or multiple systemic complications, perforation of a

visceral organ or enterocutaneous fistula, or bleeding] or death), but the mortality rate did not differ

significantly between groups (19% vs. 16%).37,38

11 Lack of clinical improvement after these initial procedures warrants consideration of minimally

invasive techniques for pancreatic necrosectomy including video-assisted retroperitoneal debridement

(VARD), minimally invasive retroperitoneal pancreatectomy (MIRP), or transluminal direct endoscopic

necrosectomy (DEN).39 VARD and MIRP use the tract created by percutaneous drainage catheters as a

guide for placement of a laparoscope into the retroperitoneum so that debridement and lavage can be

performed under direct visualization. Open necrosectomy is associated with substantial morbidity, but

to date no randomized trial has documented superiority of either minimally invasive or open surgical

technique. Additional trials are underway to address this (Algorithm 8-3). See also chapter on Acute

Pancreatitis.

SKIN AND SOFT TISSUE INFECTIONS

Skin and soft tissue infections (SSTIs) span a broad spectrum of clinical entities from limited cellulitis to

rapidly progressive necrotizing fasciitis, which may be associated with septic shock or toxic shock

syndrome and associated organ failure.40,41 These SSTIs may result in critical illness and require

management in the intensive care unit (ICU).42,43 Methicillin-resistant Staphylococcus aureus (MRSA) has

emerged as the most common identifiable cause of severe SSTIs, therefore initiation of empiric antiMRSA antimicrobials is warranted in all cases of severe SSTIs. In addition, appropriate critical care

management, including fluid resuscitation, organ support, and nutritional support are necessary

components of treatment of severe SSTIs.

The complex interplay of environment, host, and pathogen is important to consider when evaluating

SSTIs and planning therapy. The key to a successful outcome in caring for patients with severe SSTIs is

(1) early diagnosis and differentiation of necrotizing versus nonnecrotizing SSTI, (2) early initiation of

appropriate empiric broad-spectrum antimicrobial therapy with consideration of risk factors for specific

pathogens, (3) “source control,” that is, early aggressive surgical intervention for drainage of abscesses

247

http://surgerybook.net/

and debridement of necrotizing soft tissue infections (NSTIs), and (4) pathogen identification and

appropriate deescalation of antimicrobial therapy.

Algorithm 8-3. Step-up approach to management of necrotizing infected pancreatitis. (Adapted from Besselink MG, van Santvoort

HC, Nieuwenhuijs, et al.; Dutch Acute Pancreatitis Study Group. Minimally invasive ‘step-up approach’ versus maximal

necrosectomy in patients with acute necrotizing pancreatitis (PANTER trial): design and rationale of a randomized controlled

multicenter trial [ISRCTN13975868]. BMC Surg 2006;6:6.)

Table 8-10 Comparison of Old and New Classification of SSTIs by FDA

Classification of Skin and Soft Tissue Infections

The FDA previously classified SSTIs into two broad categories for the purpose of clinical trials

evaluating new antimicrobials for the treatment of SSTIs: uncomplicated and complicated (Table 8-

10). Uncomplicated SSTIs include superficial infections such as cellulitis, simple abscesses, impetigo,

and furuncles. These infections can be treated by antibiotics and/or surgical incision for drainage of

abscess alone. In contrast, complicated SSTIs include deep soft tissue infections that require significant

surgical intervention, such as infected ulcers, infected burns, and major abscesses, and these patients

also have significant underlying comorbidities, that is, disease states which complicate (and usually

delay) response to treatment. Complicated SSTIs are a significant clinical problem, in part related to the

increasing resistance of infecting bacteria to current antibiotic therapies.

248

http://surgerybook.net/

Uncomplicated Skin and Soft Tissue Infections

Uncomplicated SSTIs are associated with low risk for life- or limb-threatening infection. These patients

can be treated with empiric antibiotic therapy according to likely pathogen and local resistance

patterns.

Complicated Skin and Soft Tissue Infections

Complicated SSTIs are associated with high risk for life- or limb-threatening infection. In these patients,

it is of paramount importance to initiate appropriate and adequate broad-spectrum initial empiric

antimicrobial therapy with coverage for MRSA and to consider the need for surgical intervention for

abscess drainage or debridement.

Patients with complicated SSTIs require hospitalization for treatment. Specific circumstances that

warrant hospitalization include the presence of tissue necrosis, sepsis, severe pain, altered mental status,

immunocompromised state, and organ failure (respiratory, renal, hepatic). SSTIs can lead to serious

potentially life-threatening local and systemic complications. The infections can progress rapidly and

early recognition and proper medical and surgical management is cornerstone of therapy.

12 In October 2013, the FDA changed the SSTI terminology and issued final guidance for the

treatment of acute bacterial skin and skin structure infections (ABSSSI).44 This guidance defined ABSSSI

as cellulitis, erysipelas, wound infection, and major cutaneous abscess. An ABSSSI is defined as a

bacterial infection of the skin with a lesion size area of at least 75 cm2 (lesion size measured by the area

of redness, edema, or induration). The minimum area of involvement of 75 cm2 is chosen to select

patients with acute bacterial skin infections for which a reliable control drug treatment effect can be

estimated for the conduct of new antimicrobial treatment trials. While the FDA generally requires two

phase III trials to support approval of drugs to treat ABSSSI, this guidance stated that a single phase III

study that is supported by additional independent evidence may suffice.

Patients with the following infection types can be enrolled in ABSSSI clinical trials:

Cellulitis/erysipelas: A diffuse skin infection characterized by spreading areas of redness, edema,

and/or induration

Wound infection: An infection characterized by purulent drainage from a wound with surrounding

redness, edema, and/or induration

Major cutaneous abscess: An infection characterized by a collection of pus within the dermis or

deeper that is accompanied by redness, edema, and/or induration

Unfortunately, this new guidance does not address less serious skin infections, such as impetigo and

minor cutaneous abscess, or more serious infections needing more complex treatment regimens, such as

infections resulting from animal or human bites, NSTIs, diabetic foot infection, decubitus ulcer infection,

myonecrosis, osteomyelitis, and ecthyma gangrenosum.

Early Diagnosis and Differentiation of Necrotizing versus Nonnecrotizing SSTI

Another classification for SSTIs that is commonly used is the differentiation of NSTIs from

nonnecrotizing infections. This differentiation is critical since necrotizing infections warrant prompt

aggressive surgical debridement. Clinical clues to the diagnosis of NSTIs are listed in Table 8-3. The

differentiation of necrotizing infections from nonnecrotizing infections is critical to achieving adequate

surgical therapy.45 A clear approach to these infections must allow rapid identification and treatment of

NSTIs because they are limb threatening and life threatening.

When clinical “hard clinical signs” (bullae, crepitus, gas on x-ray, hypotension with SBP <90 mm Hg,

or skin necrosis) of NSTI are present, establishing the diagnosis of NSTI is not difficult. However, hard

signs of NSTIs are often absent on presentation, thus potentially delaying diagnosis and surgical

intervention. Studies have documented that less than 50% of patients with a definitive diagnosis of NSTI

presented with “hard clinical signs” of NSTI.46 Admission of white blood cell count >15,400 × 109/L

and/or serum sodium <135 mEq/L was documented to help differentiate NSTI from non-NSTI and

aided in early diagnosis.47,48 The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score is

also helpful as a laboratory aid in distinguishing necrotizing from nonnecrotizing SSTIs (see NSTI

section below). In retrospective studies CT scan has been shown to have a negative predictive value of

100% and a positive predictive value of 76% in diagnosing NSTI.49

If there is any question regarding the possible diagnosis of an NSTI, it is imperative to proceed with

surgical intervention and to be certain that the surgical incision is continued down to the fascial and

muscle level to make a definitive diagnosis.

249