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16. The failure of an enterocutaneous fistula to heal on a
regimen of total parenteral nutrition and anti-secretory
therapy may be due to which of the following?
A. A foreign body in the fistula tract
B. Epithelialization of the fistula tract
C. Down-stream obstruction of the fistulized segment
of intestine
D. All of the above
CHAPTER 28
17. Which of the following primary malignancies of the
small intestine is most common?
A. Adenocarcinoma of the duodenum
B. Carcinoid tumor of the ileum
C. Lymphoma of the jejunum
Small Intestine
D. Gastrointestinal stromal tumor (GIST) of the
duodenum
18. Adenocarcinoma of the duodenum is associated with
what hereditary oncologic syndrome?
A. Hereditary nonpolyposis colorectal cancer (HNPCC)
B. Familial adenomatous polyposis (FAP)
C. Peutz-Jeghers syndrome
D. Von Hipple-Lindau (VHL) syndrome
Answer: D
Factors which prevent healing of an entero-cutaneous fistula
include foreign body, epithelialization of the fistula tract,
down-stream obstruction, radiation enteritis, associated
infection (abscess or sepsis), malignancy, and a short (<2 cm)
fistula tract. (See Schwartz 11th ed., pp. 1240–1241.)
Answer: A
Adenocarcinomas of the duodenum are the most common
primary small bowel malignancy and account for 35% to 50%
of the total. Lymphoma and GIST tumors of the small bowel
are the least common and each accounts for 10% to 15% of
the total. (See Schwartz 11th ed., pp. 1241–1242.)
Answer: B
Duodenal carcinoma is a late manifestation of the FAP
syndrome. After resolution of the colonic disease by total
colectomy, patients with FAP must be followed with periodic
upper gastrointestinal (GI) endoscopy to maintain surveillance for duodenal tumors. Duodenal cancer is the leading cause of death among patients with FAP. (See Schwartz
11th ed., p. 1242.)
19. Which of the following statements is TRUE regarding
gastrointestinal stromal tumors (GISTs) involving the
small intestine?
A. Most occur in the small intestine.
B. GISTs are usually metastatic when first diagnosed.
C. GISTs typically present with gastrointestinal
hemorrhage.
D. GISTs are usually responsive to cytotoxic
chemotherapy.
20. Methods to prevent radiation enteritis of the small bowel
during pelvic irradiation for gynecologic or rectal malignancy include which of the following?
A. Tilt table positioning in Trendelenberg position dur-
ing radiation therapy treatments
B. Closure (reapproximation) of the pelvic peritoneum
after primary resection
C. Placement of an absorbable mesh sling to suspend
small intestine out of the pelvis during postoperative
radiation therapy
D. All of the above
Answer: C
GISTs are a form of sarcoma which occur most commonly
(70%) in the stomach, but comprise 10% to 15% of small
bowel malignancies. They more frequently present with gastrointestinal hemorrhage than other small bowel malignancies. They are usually refractory to conventional cytotoxic
chemotherapy but are not usually metastatic on initial diagnosis. A radical lymphadenectomy is not usually required; a
segmental resection of the involved portion of the small intestine is usually sufficient surgical treatment. Imatinib, but not
cytotoxic chemotherapy, has been shown to be therapeutic
for unresectable or metastatic disease. (See Schwartz 11th ed.,
pp. 1242–1245.)
Answer: D
In addition to limiting radiation exposure to <5000 cGy,
avoiding radiation to the small intestine after pelvic surgery
can involve steep Trendelenberg positioning during radiation
therapy sessions, closure of the pelvic peritoneum at the level
of the sacral promontory to prevent small bowel filling the
pelvis, and creating of an absorbable mesh sling to prevent
the small intestine from filling the pelvic cavity. (See Schwartz
11th ed., p. 1246.)
21. Common causes of occult gastrointestinal (GI) bleeding
include which of the following?
A. Bleeding from a Meckel diverticulum
B. Angiodysplasias of the small bowel
C. Nonsteroidal anti-inflammatory drug (NSAID)-
induced ulcers
D. All of the above
Answer: D
Hematemesis, melena, or hematochezia may occur with
occult GI bleeding, as can unexplained iron deficiency anemia. Push enteroscopy (advancing a long endoscope into the
distal small bowel) or capsule endoscopy may reveal causes
such as a bleeding Meckel diverticulum, angiodysplasias,
as well as Crohn disease or NSAID-induced ulcerations.
(See Schwartz 11th ed., pp. 1250–1251.)
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22. Short bowel syndrome has been arbitrarily defined in
adults as having a small intestine of less than what length?
A. 300 cm
B. 200 cm
C. 100 cm
D. 50 cm
23. Common causes of short bowel syndrome include all of
the following EXCEPT:
A. Mesenteric ischemia.
B. Malignancy.
C. Crohn disease.
D. Radiation enteritis.
24. After an emergency operation for bowel infarction in
which more than half of the small intestine was removed
and a jejunostomy created, high-volume ostomy losses
cause recurrent dehydration. Initial management of this
condition includes all of the following EXCEPT:
A. Proton pump inhibitors or histamine-2 receptor
antagonists.
B. Octreotide.
C. Loperamide.
D. Small bowel transplantation.
Answer: B
A functional definition in which insufficient absorptive
capacity results in diarrhea, dehydration, and malnutrition
is more appropriate, but a standard definition of short bowel
syndrome of 200 cm has been used widely. (See Schwartz
11th ed., p. 1254.)
Answer: D
In adults, the common etiologies of short bowel syndrome
include mesenteric ischemia, malignancy, and Crohn disease. In pediatric patients, common causes include intestinal
atresias, volvulus, and necrotizing enterocolitis. Radiation
enteritis usually involves isolated segments of small bowel of
<50% of total small intestinal length. (See Schwartz 11th ed.,
p. 1254.)
Answer: D
Reducing gastric secretion with proton pump inhibitors or
histamine-2 receptor antagonists, reducing gastro-enteropancreatic secretions with octreotide, and inhibiting motility
with agents such as loperamide or diphenoxylate are useful
approaches to prevent dehydration as the short gut adapts to
its new length. Small intestinal transplantation would be considered only after other therapies including total parenteral
nutrition (TPN) fail. (See Schwartz 11th ed., p. 1255.)
CHAPTER 28
Small Intestine
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CHAPTER 29
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Colon, Rectum, and Anus
1. A patient presents for evaluation of blood with wiping
and is found to have an ulcerated lesion at the anal verge,
which is biopsied and results as anal squamous cell carcinoma. How should this patient be first assessed for
lymph node involvement?
A. Computed tomography (CT) abdomen/pelvis to
assess for inferior mesenteric or internal iliac nodes
B. Whole body positron emission tomography-CT
(PET-CT)
C. Clinical examination of inguinal nodes
2. Which of the following statements is TRUE regarding
normal fecal continence and defecation?
A. Defecation requires a decrease in intra-abdominal
pressure.
B. Defecation involves contraction of the puborectalis
muscle.
C. The internal and external anal sphincter muscles are
active at rest.
D. Hemorrhoidal cushions have no role in fecal
continence.
Answer: C
Anorectal lymphatic drainage. Lymphatic drainage of
the rectum parallels the vascular supply. Lymphatic channels in the upper and middle rectum drain superiorly into
the inferior mesenteric lymph nodes. Lymphatic channels
in the lower rectum drain both superiorly into the inferior
mesenteric lymph nodes and laterally into the internal iliac
lymph nodes. The anal canal has a more complex pattern
of lymphatic drainage. Proximal to the dentate line, lymph
drains into both the inferior mesenteric lymph nodes and the
internal iliac lymph nodes. Distal to the dentate line, lymph
primarily drains into the inguinal lymph nodes, but can also
drain into the inferior mesenteric lymph nodes and internal
iliac lymph nodes. (See Schwartz 11th ed., p. 1262.)
Answer: C
Defecation. Defecation is a complex, coordinated mecha-
nism involving colonic mass movement, increased intraabdominal and rectal pressure, and relaxation of the pelvic
floor. Distention of the rectum causes a reflex relaxation of
the internal anal sphincter (the rectoanal inhibitory reflex)
that allows the contents to make contact with the anal canal.
This “sampling reflex” allows the sensory epithelium to distinguish solid stool from liquid stool and gas. If defecation
does not occur, the rectum relaxes and the urge to defecate
passes (accommodation response). Defecation proceeds by
coordinating increasing intra-abdominal pressure via a
Valsalva maneuver with rectal contraction, relaxation of the
puborectalis muscle, and opening of the anal canal.
Continence. The maintenance of fecal continence is at
least as complex as the mechanism of defecation. Continence
requires adequate rectal wall compliance to accommodate the
fecal bolus, appropriate neurogenic control of the pelvic floor
and sphincter mechanism, and functional internal and external sphincter muscles. At rest, the puborectalis muscle creates
a “sling” around the distal rectum, forming a relatively acute
angle that distributes intra-abdominal forces onto the pelvic
floor. With defecation, this angle straightens, allowing downward force to be applied along the axis of the rectum and anal
canal. The internal and external sphincters are tonically active
at rest. The internal sphincter is responsible for most of the resting, involuntary sphincter tone (resting pressure). The external
sphincter is responsible for most of the voluntary sphincter
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CHAPTER 29
tone (squeeze pressure). Branches of the pudendal nerve innervate both the internal and external sphincter. The hemorrhoidal cushions may contribute to continence by mechanically
blocking the anal canal. Finally, liquid stools exacerbate abnormalities with these anatomic and physiologic mechanisms, so
a formed stool contributes to maintaining continence. Thus,
impaired continence may result from poor rectal compliance,
injury to the internal and/or external sphincter or puborectalis,
or neuropathy. (See Schwartz 11th ed., p. 1264.)
3. A 67-year-old man is diagnosed with a rectal cancer after
undergoing colonoscopy for bloody stools and weight
loss. Which of the following statements is FALSE regarding the use of endorectal ultrasound for rectal lesions?
A. The rectal wall appears as a four-layer structure on
Colon, Rectum, and Anus
ultrasound.
B. Ultrasound can reliably distinguish between most
benign and malignant rectal polyps.
C. Ultrasound is useful for determining depth of rectal
cancer invasion.
D. Identification of involved perirectal lymph nodes via
ultrasound is possible in most cases.
Answer: A
Endorectal and endoanal ultrasound. Endorectal ultrasound
is primarily used to evaluate the depth of invasion of neoplastic lesions in the rectum. The normal rectal wall appears as a
five-layer structure (Fig. 29-1). Ultrasound can reliably differentiate most benign polyps from invasive tumors based on the
integrity of the submucosal layer. Ultrasound can also differentiate superficial T1-T2 from deeper T3-T4 tumors. Overall,
the accuracy of ultrasound in detecting depth of mural invasion ranges between 81% and 94%. This modality also can
detect enlarged perirectal lymph nodes, which may suggest
Mucosal surface
Mucosa/Muscularis mucosa
Submucosa
Muscularis propria
Serosa/Perirectal fat
A
FIG. 29-1. A. Schematic of the layers of
the rectal wall observed on endorectal
ultrasonography. B. Normal endorectal
ultrasonography. (A. Reproduced with
permission from Charles O. Finne III, MD,
Minneapolis, MN.)
B
nodal metastases; accuracy of detection of pathologically pos-
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itive lymph nodes is 58% to 83%. Ultrasound may also prove
useful for early detection of local recurrence after surgery.
(See Schwartz 11th ed., pp. 1265–1266.)
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4. A 73-year-old woman is seen in preoperative consultation for a cecal mass. You are counseling her on various
approaches to a right hemicolectomy. Which of the following are benefits of minimally invasive colon resection, when compared to open surgery?
A. Improved cosmetic results
B. Decreased postoperative pain
C. Earlier return of bowel function
D. Less expensive
E. All of the above
F. A-C
Answer: F
Minimally invasive techniques of resection. With advances
in minimally invasive technology, many procedures that
previously have required laparotomy can now be performed
laparoscopically, with hand-assisted laparoscopy (HAL), or
robotically. Potential advantages of minimally invasive surgery include improved cosmetic result, decreased postoperative pain, and earlier return of bowel function. Moreover,
some experimental data suggest that minimally invasive operations have less immunosuppressive impact on the patient
and thus might improve postoperative outcome and even
long-term survival. To date, most studies have demonstrated
equivalence between laparoscopic, HAL, and open resection
in terms of extent of resection. Return of bowel function and
length of hospital stay are highly variable. Long-term outcome has yet to be determined; however, short-term quality
of life appears to be improved by laparoscopy. Laparoscopic
total mesorectal excision for rectal cancer, however, may not
be appropriate. The most recent advances in minimally invasive surgery involve use of robotics and telemanipulation in
which the surgeon operates from a console remote from the
patient. These procedures have been rapidly gaining in popularity, especially for pelvic and rectal resections. Early studies
suggest equivalence between robotic resections and laparoscopic/HAL resections.
In addition, some proponents have suggested that robotic
procedures may be easier to learn (a shorter “learning curve”)
and that robotic surgery may be ergonomically better for
the operating surgeon. Nevertheless, long-term superiority, or even equivalence, has yet to be demonstrated, and
these advanced technologies are likely to be associated with
significant cost. (See Schwartz 11th ed., p. 1270.)
CHAPTER 29
Colon, Rectum, and Anus
5. Which of the following resections is incorrectly matched
with the vessels to be ligated?
A. Right colectomy: ileocolic, right colic, and right
branches of middle colic vessels
B. Total abdominal colectomy: ileocolic, right colic,
middle colic, left colic, sigmoidal, and superior rectal
vessels
C. Extended left colectomy: middle colic, left colic, and
first branch of sigmoid vessels
D. Transverse colectomy: middle colic vessels
E. Extended right colectomy: ileocolic, right colic, and
middle colic vessels
F. Left colectomy: left branches of middle colic, left
colic, and first branch of sigmoid vessels
Answer: B
Right colectomy. A right colectomy is used to remove lesions
or disease in the right colon and is oncologically the most
appropriate operation for curative intent resection of proximal colon carcinoma. The ileocolic vessels, right colic vessels,
and right branches of the middle colic vessels are ligated and
divided. Approximately 10 cm of terminal ileum are usually
included in the resection. A primary ileal-transverse colon
anastomosis is almost always possible.
Extended right colectomy. An extended right colectomy
may be used for curative intent resection of lesions located at
the hepatic flexure or proximal transverse colon. A standard
right colectomy is extended to include ligation of the middle
colic vessels at their base. The right colon and proximal transverse colon are resected, and a primary anastomosis is created
between the distal ileum and distal transverse colon. Such an
anastomosis relies on the marginal artery of Drummond. If
the blood supply to the distal transverse colon is questionable, the resection is extended distally beyond the splenic
flexure to well-perfused descending colon where the ileocolic
anastomosis can be performed safely.
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Colon, Rectum, and Anus
Transverse colectomy. Lesions in the mid and distal transverse colon may be resected by ligating the middle colic
vessels and resecting the transverse colon, followed by a
colocolonic anastomosis. However, an extended right colectomy with an anastomosis between the terminal ileum and
descending colon may be a safer anastomosis with an equivalent functional result.
Left colectomy. For lesions or disease states confined to the
distal transverse colon, splenic flexure, or descending colon,
a left colectomy is performed. The left branches of the middle
colic vessels, the left colic vessels, and the first branches of
the sigmoid vessels are ligated. A colocolonic anastomosis can
usually be performed.
Extended left colectomy. An extended left colectomy is an
option for removing lesions in the distal transverse colon. In
this operation, the left colectomy is extended proximally to
include the right branches of the middle colic vessels.
Sigmoid colectomy. Lesions in the sigmoid colon require
ligation and division of the sigmoid branches of the inferior mesenteric artery. In general, the entire sigmoid colon
should be resected to the level of the peritoneal reflection and
an anastomosis created between the descending colon and
upper rectum. Full mobilization of the splenic flexure is often
required to create a tension-free anastomosis.
Total and subtotal colectomy. Total or subtotal colectomy
is occasionally required for patients with fulminant colitis,
attenuated familial adenomatous polyposis (FAP), or synchronous colon carcinomas. In this procedure, the ileocolic vessels,
right colic vessels, middle colic vessels, and left colic vessels are
ligated and divided. The superior rectal vessels are preserved. If
it is desired to preserve the sigmoid, the distal sigmoid vessels
are left intact, and an anastomosis is created between the ileum
and distal sigmoid colon (subtotal colectomy with ileosigmoid
anastomosis). If the sigmoid is to be resected, the sigmoidal
vessels are ligated and divided, and the ileum is anastomosed
to the upper rectum (total abdominal colectomy with ileorectal anastomosis). If an anastomosis is contraindicated, an end
ileostomy is created, and the remaining sigmoid or rectum
is managed either as a mucus fistula or a Hartmann pouch.
(See Schwartz 11th ed., pp. 1270–1272.)
6. You are the chief resident performing an intestinal anastomosis with the help of your intern, who requests that
you share some useful facts about anastomoses. Which
of the following would be wrong to teach your intern?
A. Hand-sutured anastomoses leak less frequently than
stapled anastomoses.
B. The colon should be mobilized as much as needed to
ensure a tension-free anastomosis to the rectum.
C. The submucosal layer provides strength to an
anastomosis.
D. Performing an anastomosis in the setting of feculent
peritonitis would increase the chances of anastomotic
leak.
Answer: A
Anastomoses. Anastomoses may be created between two seg-
ments of bowel in a multitude of ways. The geometry of the
anastomosis may be end-to-end, end-to-side, side-to-end, or
side-to-side. The anastomotic technique may be hand-sewn or
stapled (Fig. 29-2). The submucosal layer of the intestine pro-
vides the strength of the bowel wall and must be incorporated
in the anastomosis to assure healing. The choice of anastomosis depends on the operative anatomy and surgeon preference.
Although many surgeons advocate one method over another,
none has been proven to be superior. Accurate approximation
of two well-vascularized, healthy limbs of bowel without tension
in a normotensive, well-nourished patient almost always results
in a good outcome. Anastomoses at highest risk of leak or stricture are those that are in the distal rectal or anal canal, involve
irradiated or diseased intestine including perforation with peritoneal soilage, are inadvertently fashioned above a partial distal
obstruction, or are performed in malnourished, immunosuppressed, or ill patient. (See Schwartz 11th ed., p. 1274.)
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CHAPTER 29
A
Colon, Rectum, and Anus
B
FIG. 29-2. A. Sutured end-to-end colocolic anastomosis.
B. Sutured end-to-side ileocolic anastomosis. C. Stapled
side-to-side, functional end-to-end ileocolic anastomosis.
(Reproduced with permission from Bell RH, Rikkers LF,
Mulholland M. Digestive Tract Surgery: A Text and Atlas.
Philadelphia, PA: Lippincott Williams & Wilkins; 1996.)
7. Your elderly female patient is scheduled for repair of her
rectal prolapse today via a transabdominal approach.
When you visit the preoperative area to see if she has any
last minute questions, she asks you why she is getting an
epidural. What can you tell her?
A. Epidural analgesia does not provide as good of pain
relief as intravenous (IV) medications, but it is safer
because of her age.
B. An epidural is being used so that general anesthesia
can be avoided due to her age and comorbidities.
C. An epidural will improve her respiratory mechanics
postoperatively.
D. She was incorrectly scheduled for an epidural and
it will be canceled, since these are only used as local
anesthesia for anorectal procedures.
C
Answer: C
Regional anesthesia. Epidural, spinal, and caudal anesthet-
ics can be used for anorectal procedures and transanal resections. In patients with severe medical comorbidity, regional
anesthesia may occasionally be used for laparotomy and colectomy. Postoperative epidural anesthesia provides excellent
pain relief and improves pulmonary function especially after
an open operation.
General anesthesia. General anesthesia is required for the
vast majority of intra-abdominal procedures. Patients should
undergo a thorough preoperative cardiovascular evaluation.
In patients with significant comorbid disease, an anesthesia
consultation may be appropriate. (See Schwartz 11th ed.,
pp. 1278–1279.)
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8. The medical student on the colorectal surgery service
astutely notes that patients who have undergone colectomies tend to have higher incisional infection rates than
patients on other services. You decide to review methods
for reducing surgical site infections with her. Which of
the following is not TRUE?
A. Mechanical bowel preparation is thought to help
clear the colon of bacteria.
CHAPTER 29
Colon, Rectum, and Anus
B. Preoperative oral antibiotics can help reduce the
rate of incisional infection, even when a mechanical
bowel prep is not used.
C. Routine postoperative intravenous (IV) antibiotics
have no role in an uncomplicated colectomy.
D. Prophylactic IV antibiotics should only be given
before incision regardless of the length of the operation, as additional doses during an operation can lead
to antibiotic resistance.
Answer: D
Bowel preparation. The rationale for bowel preparation is
that decreasing the bacterial load in the colon and rectum will
decrease the incidence of postoperative infection. Mechanical
bowel preparation uses cathartics to rid the colon of solid stool
the night before surgery. The most commonly used regimens
include polyethylene glycol (PEG) solutions or magnesium
citrate. PEG solutions require patients to drink a large volume
of fluid and may cause bloating and nausea. Magnesium citrate
solutions are generally better tolerated but are more likely to
cause fluid and electrolyte abnormalities. Both are equally
efficacious in bowel cleansing. Preparatory formulations
have been recently introduced in tablet form in an attempt to
improve tolerance. However, these methods of bowel cleansing
require ingestion of ≥40 tablets with water over several hours.
To date, these formulations have not been proven to be superior to the more traditional products. Antibiotic prophylaxis
also is recommended. The addition of oral antibiotics to the
preoperative mechanical bowel preparation has been thought
to decrease postoperative infection by further decreasing the
bacterial load of the colon. A recent analysis of the Surgical
Care Improvement Project-1 (SCIP-1) suggests that oral antibiotics reduce postoperative wound infection, especially if a
mechanical bowel preparation is not used.
Long-standing, convincing data support the efficacy of parenteral antibiotic prophylaxis at the time of surgery. Broadspectrum parenteral antibiotic(s) with activity against aerobic
and anaerobic enteric pathogens should be administered just
prior to the skin incision and redosed as needed depending
on the length of the operation. There is no proven benefit to
using antibiotics postoperatively after an uncomplicated colectomy. (See Schwartz 11th ed., p. 1279.)
9. Which of the following extraintestinal manifestations
of inflammatory bowel disease cannot be improved by
treatment of colonic disease?
A. Fatty infiltration of the liver
B. Primary sclerosing cholangitis
C. Arthritis
D. Erythema nodosum
Answer: B
Extraintestinal manifestations. The liver is a common site
of extracolonic disease in inflammatory bowel disease. Fatty
infiltration of the liver is present in 40% to 50% of patients,
and cirrhosis is found in 2% to 5%. Fatty infiltration may be
reversed by medical or surgical treatment of colonic disease,
but cirrhosis is irreversible. Primary sclerosing cholangitis
is a progressive disease characterized by intra and extrahepatic bile duct strictures. Forty percent to 60% of patients
with primary sclerosing cholangitis have ulcerative colitis.
Colectomy will not reverse this disease, and the only effective
therapy is liver transplantation. Pericholangitis is also associated with inflammatory bowel disease and may be diagnosed
with a liver biopsy. Bile duct carcinoma is a rare complication
of long-standing inflammatory bowel disease. Patients who
develop bile duct carcinoma in the presence of inflammatory
bowel disease are, on average, 20 years younger than other
patients with bile duct carcinoma.
Arthritis also is a common extracolonic manifestation of
inflammatory bowel disease, and the incidence is 20 times
greater than in the general population. Arthritis usually
improves with treatment of the colonic disease. Sacroiliitis
and ankylosing spondylitis are associated with inflammatory
bowel disease, although the relationship is poorly understood. Medical and surgical treatment of the colonic disease
does not impact symptoms.
Erythema nodosum is seen in 5% to 15% of patients with
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inflammatory bowel disease and usually coincides with
clinical disease activity. (See Schwartz 11th ed., p. 1281.)
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10. Which of the following is an incorrect statement about
the management of diverticulitis?
A. Uncomplicated diverticulitis is typically treated in
the outpatient setting.
B. Hospitalized patients who fail to improve should be
assessed with a computed tomography (CT) scan for
abscess formation.
C. Worsening abdominal pain in a patient hospitalized
with diverticulitis should be addressed with broadening of antibiotics.
D. Most patients with uncomplicated diverticulitis will
never have another episode.
Answer: C
Uncomplicated diverticulitis. Uncomplicated diverticulitis is
characterized by left lower quadrant pain and tenderness. CT
findings include pericolic soft tissue stranding, colonic wall
thickening, and/or phlegmon. Most patients with uncomplicated diverticulitis will respond to outpatient therapy with
broad-spectrum oral antibiotics and a low-residue diet. Antibiotics should be continued for 7 to 10 days. About 10% to
20% of patients with more severe pain, tenderness, fever, and
leukocytosis are treated in the hospital with parenteral antibiotics and bowel rest. Most patients improve within 48 to
72 hours. Failure to improve may suggest abscess formation.
CT can be extremely useful in this setting, and many pericolic
abscesses can be drained percutaneously. Deterioration in a
patient’s clinical condition and the development of peritonitis
are indications for laparotomy.
Most patients with uncomplicated diverticulitis will recover
without surgery, and 50% to 70% will have no further episodes. It has long been believed that the risk of complications
increases with recurrent disease. For this reason, elective sigmoid colectomy has often been recommended after the second
episode of diverticulitis, especially if the patient has required
hospitalization. Resection has often been recommended after
the first episode in very young patients and is often recommended after the first episode of complicated diverticulitis.
These general guidelines have been questioned in recent years,
and more recent studies suggest that the risk of complications
and/or need for emergent resection does not increase with
recurrent disease. Moreover, the rate of complications is rare
after elective surgery and recurrences do not increase the rate
of complications. As such, the rate of resection in all patients,
including young patients and those with complicated disease,
has decreased. (See Schwartz 11th ed., pp. 1286–1287.)
CHAPTER 29
Colon, Rectum, and Anus
11. Which of the following is not a component of the Amsterdam II criteria for the diagnosis of Lynch syndrome, or
hereditary nonpolyposis colorectal cancer (HNPCC)?
A. Three relatives affected by an HNPCC-associated
malignancy
B. One cancer occurred before the age of 40
C. One relative must be a first-degree relative of the
other two
D. Two affected generations
Answer: B
Lynch syndrome (HNPCC). Lynch syndrome is more com-
mon than familial adenomatous polyposis (FAP), but it is
still extremely rare (1%–3% of all colon cancers). The genetic
defects associated with Lynch syndrome arise from errors in
mismatch repair, the phenotypic result being microsatellite
instable (MSI). Lynch syndrome is inherited in an autosomal dominant pattern and is characterized by the development of colorectal carcinoma at an early age (average age,
40–45 years). Approximately 70% of affected individuals will
develop colorectal cancer. Cancers appear in the proximal
colon more often than in sporadic colorectal cancer and have
a better prognosis regardless of stage. The risk of synchronous
or metachronous colorectal carcinoma is 40%. Lynch syndrome may also be associated with extracolonic malignancies,
including endometrial carcinoma, which is most common in
women, and ovarian, pancreas, stomach, small bowel, biliary,
and urinary tract carcinomas. The diagnosis is made based
on family history. The Amsterdam I criteria for clinical diag-
nosis of Lynch syndrome are three affected relatives with histologically verified adenocarcinoma of the large bowel (one
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