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58 Colonic Conditions: Infectious Colitis

447

Table 58.6 Fecal microbiota transplant (FMT) for the treatment of C. difcile Infection

Indications

Contraindications Severe colitis, toxic megacolon

Recipient preparation

Technique Fecal microbiota instilled at

Post-procedure care

≥2 episodes of recurrent CDI and failure of appropriate antibiotic therapy (includes either oral vancomycin taper or daxomicin)

and other complications that may be a contraindication to colonoscopy (e.g. perforation, megacolon). Caution is advised for patients who have immunosuppression or other comorbid conditions and patients who will require continued broad spectrum antibiotics

Prior to undergoing FMT, patients undergo a 2-day bowel preparation and any antibiotics are stopped 2days before the procedure (including medications to treat C. difcile)

intervals via colonoscopy port during withdrawal starting in the cecum

Following FMT, no additional C. difcile antimicrobials are administered, also avoid any antimicrobials for as long as possible going forward (ideally at least a year)

See Algorithm inFig. 58.3

A. Abdominal ndings that are most concerning

include signs of intra-abdominal catastrophe such as peritoneal ‘signs’: rebound tenderness, guarding and abdominal wall rigidity. Another signicant nding is signicant abdominal distention that may contribute to respiratory embarrassment and distress.

B. Respiratory distress could progress to respi-

ratory failure and the need for mechanical ventilation and is a risk factor for in-hospital mortality.

C. Mental confusion and disorientation may be

attributable to several factors including systemic sepsis and respiratory embarrassment leading to oxygen desaturation.

D. Altered vital signs across the board typically

include: elevated temperature, oxygen desaturation, sinus tachycardia and hypotension. Signicant hypotension requiring vasopressor agents is another risk factor for in- hospital mortality.

E. Low urine output may be attributed to: hypo-

tension, low intra-vascular volume (dehydration) and abdominal compartment syndrome.

F. Marked leukocytosis in the 30–50,000 WBC

range with signicant bandemia often precedes the onset of hypotension and organ dysfunction. A retrospective review of 130 cases from Canada noted that patients with leukocytosis greater than or equal to 50,000 or lactate greater than or equal to 5.0mol/l had a 30-day mortality rate of 75%. At the other end of the spectrum, systemic sepsis may also manifest as a markedly depressed WBC< 1,500. Systemic sepsis may lead to disseminated intravascular coagulation (DIC) with active brinolysis, consumption of coagulation factors and functional impairment of platelets resulting in a hypocoagulable state making hemostasis difcult to achieve if an operation becomes necessary. An increase in creatinine level precedes the development of renal insufciency and perhaps renal failure. A combination of hypovolemia, hypotension and mechanical ventilation all contribute to acidosis which may manifest as a decreased pH and increased pCO

on ABGs, decreased

serum CO2 and increased serum lactic acid.

G. Bedside imaging is best for unstable ICU

patients. Plain lms may reveal colon dilation or free air if the colon has perforated. CT scans are the most sensitive indicator of CDI, but the use of IV contrast should be carefully considered because of underlying renal compromise from ongoing sepsis and the potential for renal insufciency. When obtained, CT ndings may include a thick colon wall, pericolic stranding and free exudative uid (often mistakenly referred to as ‘ascites’). CT scans predicted OR ndings in

448

Fig. 58.3 Algorithm for ominous signs/indications for emergency surgery; DIC disseminated intravascular coagulation

W. C. Cirocco and S. R. Day

94% of cases. In one retrospective series of 21 patients, CT ndings were consistent with pancolitis 66% of the time, right-side only colitis in 19% and left side only colitis in 15% of patients. Rectal sparing occurs in up to 60–70% of patients.

H. A retrospective study at a single institution

revealed that admission to a colorectal or general surgery service was independently associated with a statistically signicant decrease of in-hospital mortality. If not already involved, surgical consultation is best requested early in the downward spiral of CDI, but the reality is that surgeons are often not involved until the late stages when an operation becomes necessary. A colorectal or general surgeon should be consulted immediately when any patient with CDI is transferred to the ICU.

I. Given the presence of the above ominous

ndings, ICU admission is mandated.

J. Intravenous uid resuscitation is important

to maintain renal function and for hemodynamic support. Intravenous vasopressor support is often required to maintain hemodynamic stability.

K. Mechanical ventilator support often becomes

necessary as respiratory embarrassment from acute abdominal distension progresses to respiratory failure.

L. Broad spectrum intravenous antibiotics are

appropriate as emergency surgery becomes necessary and concern for gut bacterial translocation in severe colitis or perforation.

M. The indications for emergent operation

include: peritonitis, megacolon, refractory sepsis, progressive organ dysfunction and, rarely, perforation. Patients with malignancy, immunosuppression, renal insufciency or patients on antiperistaltic agents are at increased risk for requiring surgical intervention. When the decision for emergency subtotal colectomy and end ileostomy becomes inevitable, a surgical checklist prepares the patient and is helpful to the surgeon (Table 58.7). Fulminant CDI carries a high postoperative mortality rate in the range of 32–100%. In a retrospective study of 14 patients, those patients with multiple organ failure had a mortality rate of 67% vs. 13.5% for patients without multiple organ failure. Total abdominal colectomy or subtotal colectomy has been labeled the ‘operation of choice’ or the gold standard of operations. Often, patients in septic shock will have a dramatic and perhaps even immediate normalization of their vital signs as the specimen is nally physically removed and handed off the OR table. The appearance of the colon

58 Colonic Conditions: Infectious Colitis

Table 58.7 Checklist for emergent surgery

✓ Category Details

Labs – CBC (Hgb, platelets) – PT/PTT – ABGs – Electrolytes (K

Blood products – FFP – PRBC – Pooled platelets – Cryoprecipitate

Invasive lines – CVC (swan) – Arterial line

Stoma site marking Enterostomal therapist ICU bed Vasopressor agents Need for pressure support may decrease dramatically following removal of

Antibiotic coverage Perioperative antibiotics to cover a broad spectrum of organisms due to

, Na+, Mg+)

Depending on results of labs, transfusion of blood products may be required prior to OR or during operation

Transfusion on a case by case basis, dependent on underlying health of the patient, including recent chemotherapeutics and development of DIC

the specimen (colon)

concern for gram negative sepsis and possible gut bacterial translocation

449

may be deceptively benign with full thickness ischemia rare and occurring very late in the course of the disease. If there are physical signs of colon ischemia or advanced CDI (either on gross examination in the OR or on endoscopic examination), it is typically more pronounced in the proximal colon with gradual physical improvement in a proximal-todistal direction. In the OR, as the colon resection progresses in a proximal-to-distal direction, the end point of colectomy may be tailored to the rectosigmoid/distal sigmoid colon to remove conuent disease while perhaps leaving a viable distal sigmoid either as a mucous stula or more simply a stapled Hartmann’s pouch (subtotal colectomy). Therefore, if the patient should survive surgery and become a candidate for reestablishment of intestinal continuity, the functional result of an ileal-distal sigmoid anastomosis may theoretically be an improvement over the function of an ileorectal anastomosis. In general, the literature regarding non-resection operations for severe CDI, including ileostomy and cecostomy, reveals that patients have “fared poorly”.

Acknowledgements Disclosures: None.

Colonic Conditions: Benign Colonic Neoplasia

TarynE.Hassinger andCharlesM.Friel

Refer toAlgorithm inFig. 59.1

A. Benign colonic neoplasia can be divided into

two primary categories, adenomatous polyps and serrated polyps. Adenomatous polyps comprise approximately two-thirds of all colonic polyps, making them the most common of the neoplastic polyps. They are categorized by their gross appearance into sessile, pedunculated, at, or depressed lesions. Histologically, these lesions are further identied as tubular, villous, or tubulovillous adenomas. Serrated polyps are the second most common subtype of benign colonic neoplasia. This group includes a heterogeneous group of lesions including hyperplastic polyps, traditional serrated adenomas (TSA), and sessile serrated polyps/ adenomas (SSA/P). Other less common types of benign colonic neoplasia include hamartomatous polyps.

B. Regardless of the type of neoplastic lesion,

they are most often discovered incidentally on screening endoscopy, thus typically in patients over 50years of age. Small lesions are unlikely to cause bleeding, but larger more advanced polyps can cause chronic, slow bleeding and thus result in positive fecal

T. E. Hassinger · C. M. Friel (*) Department ofSurgery, University ofVirginia Medical Center, Charlottesville, VA, USA e-mail: CMF2X@hscmail.mcc.virginia.edu

occult blood testing and anemia. Less commonly, a large lesion can cause obstructive symptoms, a presentation more often seen with adenomatous polyps.

C. Once a polyp is discovered, a complete colo-

noscopy should be performed to inspect for synchronous polyps and/or cancers if the original endoscopic procedure did not completely clear the colon.

D. Adenomatous polyps are the most common

type of benign colonic neoplasia. They are more common in men, and risk factors also include older age and obesity. These lesions are grossly categorized as sessile, pedunculated, at, or depressed. Sessile polyps have their bases attached to the colon wall, and pedunculated lesions have a mucosal stalk connecting the polyp to the colon wall. Flat polyps have a height less than half the lesion’s diameter, and depressed polyps have an excavated appearance. Histologically, adenomas are further categorized by their glandular architecture. Tubular adenomas are the most predominant, representing over 80% of colonic adenomas. They are composed of a network of branching epithelium. An adenoma’s structure must be at least 75% tubular in order to be classied as a tubular adenoma. Villous adenomas comprise 5–15% of adenomas and contain long, straight glands from the surface epithelium to the center of the polyp. To be considered a villous polyp, the

https://doi.org/10.1007/978-3-319-65942-8_59

451

452

Fig. 59.1 Algorithm for benign colonic neoplasia. EMR endoscopic mucosal resection, ESD endoscopic submucosal dissection, CELS combined endoscopic laparoscopic surgery, TAE transanal excision, TEM transanal endoscopic microsurgery, TAMIS transanal minimally invasive surgery

T. E. Hassinger and C. M. Friel

lesion must contain at least 75% villous components. Finally, tubulovillous adenomas account for 5–15% of colonic adenomas. To be classied as tubulovillous, an adenoma must contain 26–75% villous components. In all adenomas, the area of proliferation is mainly located in the upper part of the crypt.

Adenomatous polyps are dysplastic lesions, and they are described as having high-grade or low-grade dysplasia. The degree of dysplasia impacts the risk of colorectal cancer progression, with highgrade dysplasia imparting a higher risk. Villous adenomas and polyps over 1 cm in diameter are at increased risk of harboring high-grade dysplasia or progressing to colorectal cancer. Additionally, villous histology, presence of high-grade dysplasia, and larger numbers of polyps impart an increased risk for development of metachronous colorectal cancer. Due to their obligatory presence of dysplasia, adenomatous polyps should be removed endoscopically. If unable to resect endoscopically, surgical resection should be considered. The ongoing risk of future polyp development and metachronous colorectal cancer mandates that these patients continue to undergo surveillance colonoscopy.

E. Histologically, serrated polyps are character-

ized by glandular serration with a luminal saw-toothed pattern in epithelial crypts. Hyperplastic polyps are the most common subtype, comprising over 75% of serrated polyps. These are typically at, pale lesions located at the end of rectosigmoid mucosal folds with the proliferation zone located near the bottom of the crypts. They are commonly less than 5mm in diameter and do not contain dysplasia. While they develop at a younger age than adenomas, hyperplastic polyps do not substantially increase in frequency with age. It is rare for small (≤1cm), distally located hyperplastic polyps to develop into colorectal cancer. Alternatively, large hyperplastic polyps are considered to be precursor lesions to SSPs, and as such can progress to cancer. Given this, patients with small, distal hyperplastic polyps should follow normal colorectal screening guidelines.

Sessile serrated polyps are the newest identied members of the serrated group, representing 15–20% of these polyps. These lesions are at or mildly elevated, greater than 5mm in diameter, and most commonly found in the proximal colon. Dysplasia is also typically absent, but the proliferation

59 Colonic Conditions: Benign Colonic Neoplasia

453

causes asymmetry of the crypts with some inverted crypts found below the muscularis mucosae (pseudo-invasion).

Traditional serrated adenomas are the least common of the serrated polyps, comprising just 5% of the group. They do, however, have a slightly higher prevalence in Asia. These lesions are usually located in the left colon and are more common in the elderly. They are exophytic lesions, histologically characterized by prominent serration and ectopic crypt formation with a loss of crypt orientation toward the muscularis mucosae. Unlike the other serrated polyps, TSAs do contain dysplasia.

Both SSPs and TSAs carry an increased risk of malignant degeneration and should be managed similarly to adenomatous polyps. The molecular pathway leading to cancer from a SSP differs from the chromosomal instability pathway associated with an adenomatous polyp. These cancers are usually associated with hypermethylation of the promoter region of MLH1. This epigenetic phenomenon results in underexpression of MLH1, resulting in tumors that are microsatellite unstable, CpG island methylator phenotype (CIMP)-high, and predominantly right-sided. Sessile serrated polyps can be very difcult to detect and can easily be missed during a colonoscopy. This may account, in part, for the observation that tumors detected following a reportedly normal colonoscopy are more likely to be microsatellite unstable and CIMP-high.

The at nature of these polyps can also cause difculty with complete endoscopic removal, and surgical resection can be a potential option in these cases. In addition, patients with distal serrated polyps appear to be at increased risk of synchronous and metachronous adenomas or colorectal cancer, predicating the need for continued endoscopic surveillance.

F. Hamartomatous polyps are rare, but are the

most common polyps diagnosed in children. These polyps are also more commonly symptomatic, presenting with rectal bleeding,

abdominal pain, obstruction, or anemia. They are typically cherry-red and pedunculated, varying in size. Histologically, hamartomatous polyps are divided into juvenile polyps and Peutz-Jeghers polyps.

Juvenile polyps are composed of normal epithelium with a dense stroma, inammatory inltrate, and dilated mucus-lled cystic glands. As implied by in the name, these polyps are the most common gastrointestinal polyps in children, though they can be diagnosed at any age. Juvenile polyps are typically located in the rectosigmoid region and are removed endoscopically when found due to bleeding risk. These polyps may be associated with adenomas and colorectal cancer, but this event appears quite rare. If there are multiple (i.e., juvenile polyposis syndrome), genetic testing may be required. If they are symptomatic and are not amenable to endoscopic removal, surgery may be required.

Peutz-Jeghers polyps are multilobulated with a papillary surface and branching bands of hyperplastic glandular mucosa overlying smooth muscle contiguous with the muscularis mucosae. They are usually, but not always, associated with Peutz-Jeghers syndrome and are most often found in people over the age of 40. Solitary Peutz-Jeghers polyps can harbor dysplasia and have been known to result in colorectal cancer. Given their association with Peutz-Jeghers syndrome, polypectomy plus colonoscopy and endoscopy is recommended.

G. There are numerous treatment modalities

available for benign colonic neoplasia, varying based on the size and location of the lesion. The ultimate goals are to completely remove the neoplastic tissue and to provide an adequate tissue sample for pathological review. Most colonic polyps detected on colonoscopy are less than 10mm in diameter. These small lesions have a low risk of dysplasia, and therefore resection techniques must be low risk. Polypectomy utilizing cold forceps is appropriate for lesions less than 3mm in diameter. The lesion will often be removed with one bite, but a second pass can

454

be utilized. Risks of this procedure are quite low. Utilization of hot forceps is no longer recommended, especially in the right colon, given the increased risk of bleeding and perforation with this technique. Cold snaring is the preferred technique for lesions up to 7 mm in size (Fig. 59.2). The resection should include a small margin of normal tissue to ensure complete removal of the polyp. Hot snaring can be used for polyps over 7mm in diameter. Pedunculated lesions are also appropriate for hot snaring given the increased risk of bleeding.

H. Endoscopic mucosal resection (EMR) is used

to remove larger (1.5–2cm), sessile polyps (Fig. 59.3). This technique is frequently

T. E. Hassinger and C. M. Friel

Fig. 59.2 Small sessile polyp amenable to cold snare polypectomy. (Image provided by Charles M.Friel, MD, University of Virginia)

Fig. 59.3 Endoscopic mucosal resection (EMR) of a large ascending colon polyp. (a) Large ascending colon polyp. (b) Piecemeal EMR using snare cautery. (c) Final result showing complete resection. Tattoo placed for

subsequent surveillance. (These images were provided

courtesy of Andrew Y. Wang, MD, Division of Gastroenterology and Hepatology, University of Virginia Health System)

59 Colonic Conditions: Benign Colonic Neoplasia

455

facilitated with submucosal injection of saline to lift the mucosal or submucosal lesion off of the muscularis propria. Because of the larger size, these lesions are typically then removed in a piecemeal fashion using electrocautery. Notably, piecemeal resection does make it more difcult for histologic evaluation, which is a concern for lesions found to have malignant foci.

I. Endoscopic submucosal dissection (ESD) is

a more technically demanding variant of EMR (Fig. 59.4). This technique requires specialized training and involves submucosal injection with circumferential dissection of the involved mucosa and submucosa with diathermic knives. The goal is to accomplish

an en bloc resection rather than a piecemeal resection. As such, this technique is mainly utilized for lesions felt to have a higher risk of harboring a malignancy. Additionally, submucosal tattooing should be considered when removing large polyps to allow for identication during follow-up colonoscopy or surgery (Fig.59.5).

J. Combined endoscopic and laparoscopic sur-

gery (CELS) is a newer alternative to segmental colonic resection for patients with an endoscopically unresectable polyp proximal to the rectum. This technique allows a laparoscopic surgeon to manipulate the bowel wall to allow for easier endoscopic polypectomy. Patients with a benign colonoscopic

Fig. 59.4 Endoscopic submucosal dissection (ESD) of a large sessile polyp. (a) Circumferential markings were placed at least 5mm from the edge of the polyp, and the polyp was lifted using a solution of 6% Hetastarch tinted with methylene blue. (b) Circumferential incision (c) fol-

lowed by submucosal dissection performed using ESD knives and specialized electrosurgical generator. (d) Final result with tattoo markings. (Images provided courtesy of

Andrew Y.Wang, MD, Division of Gastroenterology and Hepatology, University of Virginia Health System)

456

Fig. 59.5 Endoscopic tattooing of a colonic lesion. (Image provided by Charles M.Friel, MD, University of Virginia)

biopsy or a biopsy with high-grade dysplasia and benign appearance on endoscopy are eligible. Due to the necessary bowel manipulation, this technique is most useful in patients without an extensive abdominal surgical history. The patient is placed in modied lithotomy position, and carbon dioxide colonoscopy is performed to prevent the over-dilation of the colon. The endoscopist injects submucosal dilute indigo carmine solution to lift the polyp and help prevent a full-thickness injury. Endoscopic piecemeal resection is then performed. The laparoscopic surgeon can help manipulate the bowel to optimize the resection. Furthermore, the surgeon can visualize the bowel and place sutures if there is concern for a full thickness burn or perforation. An additional benet of CELS includes the ability to immediately proceed to laparoscopic segmental resection if still unable to resect the polyp endoscopically or if visual ndings are consistent with malignancy.

K. Large polyps in the distal rectum can be

resected via transanal excision (TAE) with primary closure. This can be done in the submucosal plane, or a full-thickness resection can be performed if there is a high suspicion for malignancy. Endoscopic ultrasound is often performed prior to this procedure to ensure there is no invasion into the submucosa.

T. E. Hassinger and C. M. Friel

L. Transanal endoscopic microsurgery (TEM)

and transanal minimally invasive surgery (TAMIS) are minimally invasive techniques that can be used to resect rectal polyps up to 18cm from the anal verge, which is higher than can be accessed with TAE.Specialized equipment is used to perform a submucosal or full-thickness resection with primary closure. The recurrence rate with these techniques is lower than with TAE and is thus typically preferred. For those lesions that are too large for minimally invasive techniques, a surgical resection may be necessary.

M. Finally, if the polyp cannot be resected by any

of these endoscopic techniques, a surgical resection is necessary, assuming the patient is medically t. This latter point is critical to understand. When proceeding to surgical resection the surgeon must balance the risk of surgery with the potential benet, remembering that the primary goal of surgery is to prevent a future cancer. If the patient’s life expectancy is limited by either patient age and/or medical conditions, it may be prudent not to proceed with surgical resection.

On the other hand, once there is a decision to proceed to surgery it should be noted that these high-risk polyps could harbor occult cancer in up to 20% of patients. Therefore, surgical resection should follow the principles of an oncologic resection—including a high ligation of the appropriate vessels—so that if an occult invasive lesion is discovered on pathological review, the proper operation has been performed (Fig.59.6). This is particularly true in very large polyps or those with high-grade dysplasia noted on preoperative biopsies.

N. Ablative techniques can also be used for pol-

yps not easily resected by endoscopic means. The polyp is destroyed using an energy device, most commonly with electrocautery or an argon plasma coagulator (APC). Ablative techniques are generally not as effective as resection but can be used in highrisk patients or following a piecemeal resection to ablate areas that may not have been fully resected (Fig.59.7).

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