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CHAPTER 26
Stomach
reconstruction as a Roux-en-Y gastrojejunostomy should be avoided (Fig. 26-5). Although the Roux-en-Y operation is an excellent procedure for keeping duodenal contents out of the stomach and esophagus, in the presence of a large gastric rem­nant, this reconstruction will predispose to marginal ulceration and/or gastric stasis. (See Schwartz 11th ed., p. 1129.)
AB C
FIG. 26-4. A through C. Billroth II antecolic gastrojejunostomy. (Reproduced with permission from
Zinner MJ, Schwartz SI, Ellis H. Maingot’s Abdominal Operations, 10th ed. Vol. I. Stamford, CT: Appleton & Lange; 1997.)
<50% gastric
remnant
50 to 60 cm
FIG. 26-5. Roux-en-Y gastrojejunostomy.
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11. A 78-year-old man with good functional status undergoes evaluation for a newly diagnosed focal antral gastric cancer including cross-sectional imaging, endo­scopic ultrasound, and diagnostic laparoscopy. Studies indicate a T2N0 tumor. The least appropriate treatment approach is: A. Subtotal D2 gastrectomy alone. B. Subtotal D2 gastrectomy followed by chemotherapy. C. Initial systemic therapy followed by subtotal D2
gastrectomy.
D. Subtotal gastrectomy with removal and assess-
ment of >16 regional lymph nodes and adjuvant chemoradiotherapy.
E. Endoscopic resection.
12. Which of the following is not TRUE of hereditary diffuse gastric cancer (HDGC)? A. It is associated with a mutation in the E-cadherin
gene.
B. Lifetime risk of gastric cancer in affected women is
greater than in men.
C. It is associated with an increased risk of lobular breast
cancer.
D. Presentation with clinically significant gastric cancer
is associated with a very poor prognosis.
Answer: E
Multimodality approaches to gastric cancer have become well entrenched with randomized studies from the United States and Europe supporting adjuvant chemoradiotherapy and perioperative chemotherapy approaches. Evidence from Asia supports adjuvant chemotherapy after gastrectomy with extended regional lymphadenectomy (ie, D2 lymphadenec­tomy). Although T2N0 cancers were included in some of the randomized trials, such cases were probably underrep­resented and the absolute benefit of multimodality therapy in this context may not be as great as in the overall cohort of patients with locally advanced disease. Selective omission of adjuvant therapy in patients with more favorable surgical pathology may be appropriate. T2 tumors are not well treated with endoscopic resection given a prohibitive risk of recur­rence. (See Schwartz 11th ed., pp. 1139–1149.)
Answer: B
Mutations in the E-cadherin gene (CDH1) are associated with HDGC. The lifetime risk of gastric cancer is approximately 70% in men and 56% in women. Mutation-carrying women are at increased risk for breast cancer, typically lobular carci­nomas. Because of the poor prognosis associated with clini­cal gastric cancer in this setting and limitations of existing surveillance protocols, prophylactic gastrectomy is a consid­eration in individuals with CDH1 mutations. (See Schwartz 11th ed., p. 1143.)
CHAPTER 26
Stomach
13. The most common premalignant condition for early gastric cancer is: A. Gastric adenoma. B. Chronic ulcer. C. Hamartomatous polyp. D. Atrophic gastritis.
14. A patient presents with gastric cancer diagnosed on endoscopy performed for weight loss and abdomi­nal fullness. Cross-sectional imaging shows a diffusely thickened stomach with regional adenopathy. There is no evidence of distant metastatic disease. Initial manage­ment should include: A. Diagnostic laparoscopy with peritoneal lavage. B. Consideration of enteral access for nutrition support. C. Systemic chemotherapy. D. Total gastrectomy. E. A, B, and C.
Answer: D
Some patients with atrophic gastritis develop intestinal metaplasia in the gastric mucosa that may progress to dys­plasia and then to gastric cancer. Numerous cofactors have been implicated, including diet, altered gastric microbiome, genetics, and hypergastrinemia. Patients with atrophic gas­tritis are at risk for gastric cancer and should undergo peri­odic endoscopic surveillance. Metaplastic atrophic gastritis and dysplastic atrophic gastritis in particular are markers of increased risk for gastric cancer.
By far the most common precancerous lesion is atrophic gastritis. There is a growing appreciation of the important influence of the chronic inflammatory milieu on the genome of mucosal cells. Chronic inflammation leads to both genetic and epigenetic changes in mucosal cells, which in the stom­ach leads to the development of gastritis-associated cancer. (See Schwartz 11th ed., pp. 1138–1139; 1141–1142.)
Answer: E
Diagnostic laparoscopy with peritoneal lavage has emerged as an important component of the staging of gastric cancers and reveals microscopic or macroscopic disseminated disease in up to 36% of cases in published series. Diffuse gastric cancers are often diagnosed at an advanced stage. In the context of a clini­cal picture consistent with linitis plastica, distant metastasis is usually present. Although gross disease may be technically resectable with total gastrectomy, initiation of systemic therapy is usually a more pressing priority. Enteral access and supple­mental nutrition may improve candidacy for systemic therapy in selected cases. (See Schwartz 11th ed., pp. 1139–1149.)
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15. A fifty-year-old man undergoes resection of a 5 cm gas­trointestinal stromal tumor (GIST) involving the fundus of the stomach. Pathology indicates 12 mitoses/50 HPF. Molecular testing shows a KIT mutation. Subsequent management should include: A. Clinical follow-up alone. B. Clinical follow-up with periodic surveillance imag-
ing alone.
CHAPTER 26
Stomach
C. Adjuvant Imatinib for 1 year. D. Adjuvant Sunitinib for at least 3 years. E. Adjuvant Imatinib for at least 3 years.
16. Which of the following options is the best initial man­agement of a low-grade mucosa-associated lymphoid tis­sue (MALT) lymphoma of the gastric antrum? A. Helicobacter pylori eradication B. Chemotherapy +/– radiation therapy C. Wedge resection D. Antrectomy
Answer: E
Risk of GIST recurrence after resection reflects the location of the tumor (gastric tumors are less likely to recur than non­gastric tumors), size, and mitotic rate. Mitotic rate >5/50 HPF is the strongest predictor of recurrence. Patients at higher risk of recurrence should be treated with adjuvant Imatinib bar­ring the presence of a PDGFRA D842V mutation, which is associated with Imatinib resistance. Duration of treatment for 3 years proved superior to 1 year in the Scandinavian Sar­coma Group XV111 trial and there is increasing momentum for indefinite treatment after resection of high-risk disease. (See Schwartz 11th ed., pp. 1149–1151.)
Answer: A
Low-grade MALT lymphoma, essentially a monoclonal pro­liferation of B cells, presumably arises from a background of chronic gastritis associated with H. pylori. These relatively innocuous tumors then undergo degeneration to high-grade lymphoma, which is the usual variety seen by the surgeon. Remarkably, when the H. pylori is eradicated and the gastritis improves, the low-grade MALT lymphoma often disappears. Thus, low-grade MALT lymphoma is not a surgical lesion. Careful follow-up is necessary particularly in those lesions with a t (11:18) translocation, thought to be a risk factor for a more aggressive MALT lesion. (See Schwartz 11th ed., p. 1149.)
17. Type III gastric carcinoid tumors: A. Often do not require resection. B. Are associated with hypergastrinemia. C. Are sporadic lesions. D. Have better outcomes than type I and II tumors.
18. In the patient with a normal liver and endoscopic diag­nosis of watermelon stomach (gastric antral vascular ectasia [GAVE]), chronic blood loss requiring multiple transfusions is best treated by: A. Proton pump inhibitors and Carafate. B. Beta blockers. C. Distal gastrectomy. D. Total gastrectomy.
Answer: C
Type III gastric neuroendocrine tumors are sporadic. They are most often solitary (usually >2 cm) and occur more com­monly in men. They are not associated with hypergastrin­emia. Most patients have regional nodal or distant metastases at the time of diagnosis, and some present with symptoms of carcinoid syndrome. (See Schwartz 11th ed., p. 1151.)
Answer: C
The parallel red stripes atop the mucosal folds of the distal stomach give this rare entity its name. Histologically, gastric antral vascular ectasia (GAVE) is characterized by dilated mucosal blood vessels that often contain thrombi, in the lamina propria. Mucosal fibromuscular hyperplasia and hya­linization often are present (Fig. 26-6). The histologic appear­ance can resemble portal hypertensive gastropathy, but the latter usually affects the proximal stomach, whereas water­melon stomach predominantly affects the distal stomach.
FIG. 26-6. Gastric antral vascular ectasia (watermelon
stomach). (Reproduced with permission from Godlman H, Hayek J, Federman M. Gastrointestinal Mucosal Biopsy. New York, NY: Churchill Livingstone; 1996.)
19. Treatment for severe early dumping after gastrectomy
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that is persistent despite an antidumping diet and fiber is: A. Expectant management. B. Oral glucose for symptoms. C. Octreotide. D. Surgical conversion to a Roux-en-Y drainage.
Beta blockers and nitrates, useful in the treatment of portal hypertensive gastropathy, are ineffective in patients with gas­tric antral vascular ectasia. Patients with GAVE are usually elderly women with chronic gastrointestinal (GI) blood loss requiring transfusion. Most have an associated autoimmune connective tissue disorder, and at least 25% have chronic liver disease. Nonsurgical treatment options include estrogen and progesterone, and endoscopic treatment with the neo­dymium yttrium-aluminum garnet (Nd:YAG) laser or argon plasma coagulator. Antrectomy may be required to control blood loss, and this operation is quite effective but carries increased morbidity in this elderly patient group. Patients with portal hypertension and antral vascular ectasia should be considered for transjugular intrahepatic portosystemic shunt (TIPSS). (See Schwartz 11th ed., p. 1154.)
Answer: C
A variety of hormonal aberrations have been observed in early dumping, including increased serum levels of vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), neuro­tensin, peripheral hormone peptide YY, renin-angiotensin­aldosterone, and decreased atrial natriuretic peptide. Late dumping is associated with hypoglycemia and hyperinsu­linemia. Medical therapy for the dumping syndrome consists of dietary modification and somatostatin analogue (octreo­tide). (See Schwartz 11th ed., p. 1157.)
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Stomach
20. Ménétrier disease is characterized by: A. Hypertrophic gastric folds and hypoproteinemia. B. A tortuous submucosal congenital arteriovenous
malformation. C. Gastric antral vascular ectasia. D. Epithelial hyperplasia and hypergastrinemia.
Answer: A
There are two clinical syndromes characterized by epithe­lial hyperplasia and giant gastric folds: Zollinger-Ellison syndrome (ZES) and Ménétrier disease. The latter is char­acteristically associated with protein-losing gastropathy and hypochlorhydria. There are large rugal folds in the proximal stomach, and the antrum is usually spared. Mucosal biopsy shows diffuse hyperplasia of the surface mucus-secreting cells and usually decreased parietal cells (Fig. 26-7). It has recently been suggested that Ménétrier disease is caused by local over­expression of transforming growth factor-A in the gastric mucosa, which stimulates the epidermal growth factor recep­tor, a receptor tyrosine kinase, on gastric surface epithelial cells (SECs). This results in the selective expansion of surface mucous cells in the gastric body and fundus. A few patients with this unusual disease have been successfully treated with the epidermal growth factor receptor blocking monoclonal antibody cetuximab. (See Schwartz 11th ed., pp. 1153–1154.)
FIG. 26-7. Mucosal biopsy in Ménétrier’s disease.
(Reproduced with permission from Ming S-C, Goldman H. Pathology of the Gastrointestinal Tract, 2nd ed. Baltimore, MD: Williams & Wilkins; 1998.)
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CHAPTER 27
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The Surgical Management of Obesity
1. What body mass index [BMI or wt (kg)/height (m2)] definition of obesity serves as the standard indication for bariatric surgery when medical therapy has failed and comorbid conditions exist? A. Overweight (BMI 25.0–29.9) B. Class I obesity (BMI 30.0–34.9) C. Class II obesity (BMI 35.0-39.9) D. Class III obesity (BMI ≥ 40)
2. Which of the following bariatric procedures is primarily intended to induce weight loss through malabsorption of ingested nutrients? A. Jejunoileal bypass B. Sleeve gastrectomy C. Roux-en-Y gastric bypass D. Duodenal switch
3. Complications of adjustable gastric banding which have diminished its popularity as a bariatric procedure include all of the following EXCEPT: A. Mortality risk. B. Slippage of the band. C. Failure to lose weight. D. Port and tubing complications.
Answer: C
A 1991 NIH Consensus Conference recommended that bariatric surgery was indicated for a BMI of 35.0 to 39.9 when medical therapy has failed and comorbid conditions exist. When no comorbid conditions exist, a BMI of ≥40 is required. This standard continues to be used by insurers, although recent studies have shown benefit in lower BMI groups. (See Schwartz 11th ed., pp. 1169–1170 and Table 27-2 p. 1175.)
Answer: A
Bariatric procedures are classified as restrictive, malabsorp­tive, or a combination of restrictive and malabsorptive in the mechanism of weight loss that they induce. Restrictive operations include adjustable gastric band and gastric sleeve, malabsorptive operations include jejunoileal bypass and its derivatives, and combined restrictive and malabsorptive pro­cedures include the Roux-en-Y gastric bypass. (See Schwartz 11th ed., p. 1168.)
Answer: A
The adjustable gastric band procedure, usually performed laparoscopically, has the lowest cost and mortality risk of all the bariatric procedures, but is the least effective for weight loss. In addition, slippage and erosion of the band and com­plications related to the maintenance and use of the port for adjusting the size of the band contribute to its loss of popular­ity. (See Schwartz 11th ed., p. 1188.)
4. Early postoperative complications after a Roux-en-Y gastric bypass (RYGB) procedure include all of the fol­lowing EXCEPT: A. Hematemesis. B. Dilation of the distal gastric remnant. C. Pulmonary embolus. D. Hyperglycemia.
Answer: D
Early postoperative complications after RYGB include hematemesis due to bleeding from the gastrojejunal staple or suture line, gastric remnant dilation due to down-stream obstruction, and pulmonary complications such as atelec­tasis and pulmonary embolus. Diabetes, if present, usually improves promptly after RYGB and hyperglycemia is unlikely to be problematic. (See Schwartz 11th ed., p. 1185.)
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5. Small bowel obstruction after Roux-en-Y gastric bypass (RYGB) should be treated as an urgent surgical emer­gency because: A. It is frequently due to an incarcerated internal hernia
which can progress to bowel necrosis and perforation. B. Abdominal distension risks disruption of suture lines. C. Signs and symptoms of peritonitis, such as pain, fever,
and leukocytosis, are usually masked in the obese.
CHAPTER 27
The Surgical Management of Obesity
D. Nasogastric intubation will not decompress the distal
gastric remnant.
6. A late complication of Roux-en-Y gastric bypass is the development of post-gastric bypass hypoglycemia (PGBH) due to inappropriately elevated insulin levels. Recommended treatments of this condition include all of the following EXCEPT: A. Very low carbohydrate diet. B. Anti-secretory agents such as diazoxide and
somatostatin. C. GLP-1 receptor antagonists. D. Pancreatic resection.
Answer: A
Small bowel obstruction after RYGB is frequently due to an incarcerated internal hernia at the location of the closure, or lack thereof, of the mesenteric defect. This can progress rapidly to strangulation and necrosis of the bowel with subsequent perfo­ration. Adverse outcomes with this complication have resulted in the uniform recommendation that small bowel obstruc­tion in this setting should be regarded as a surgical emergency. Abdominal distention and difficulties with nasogastric intuba­tion are not relevant concerns. (See Schwartz 11th ed., p. 1184.)
Answer: D
PGBH occurs in some patients after Roux-en-Y gastric bypass due to exaggerated or excessive insulin levels. It is thought to be a consequence of greatly increased GLP-1 levels seen in some patients. A very low carbohydrate diet may provide relief in some patients, and diazoxide and somatostatin have been used in those who fail diet therapy. Recently GLP-1 recep­tor antagonists have been reported to be successful. Although pancreatic resection was initially reported in patients with severe hypoglycemia, it is no longer recommended. Partial pancreatectomy results in a recurrence of the problem, and total pancreatectomy exchanges one severe condition for another. (See Schwartz 11th ed., pp. 1204–1205.)
7. Complications which are associated with the gastric sleeve procedure include: A. Leak from the gastric staple line. B. Gastroesophageal reflux. C. Stenosis of the gastric sleeve. D. All of the above.
8. In addition to the effects of weight loss, the resolution of type 2 diabetes mellitus after the gastric sleeve procedure and Roux-en-Y gastric bypass (RYGB) is thought to be contributed to by: A. Reduced ghrelin production. B. Increased secretion of GLP-1. C. Appetite suppression. D. All of the above.
9. Adolescent patients with morbid obesity are increasingly being referred for consideration of bariatric procedures due to failure of medical management and the risks associated with a lifetime of obesity. What nutritional deficiencies require lifelong treatment after Roux-en­Y gastric bypass (RYGB), the most common procedure performed in this age group? A. Pernicious anemia due to vitamin B12 deficiency B. Iron deficiency anemia C. Deficiencies of vitamins A, E, D, and K D. All of the above
Answer: D
The gastric sleeve procedure creates a high pressure tube. This places the gastric staple line at risk for leak, and addi­tional buttress sutures are frequently used to reinforce the staple line. The high pressure also increases the probability of gastroesophageal reflux disease (GERD) so patients with a history of GERD are less favorable candidates for the gastric sleeve procedure. The gastric tube itself is usually constructed over a 40-French bougie. If a smaller bougie is used, the risk of leak and reflux are increased and stenosis of the gastric sleeve or tube may occur. (See Schwartz 11th ed., p. 1186.)
Answer: D
Gastrectomy removes much of the ghrelin-producing portion of the stomach and this mechanism is thought to contribute to weight loss after both gastric sleeve and RYGB procedures. GLP-1, the enteric hormone which augments insulin release, is dramatically increased after RYGB, and is increased after the gastric sleeve procedure as well. A profound suppression of appetite and food craving has been found to follow these procedures, presumably due to the altered hormonal status of peptides which affect the satiety centers of the central nervous system. (See Schwartz 11th ed., p. 1175.)
Answer: D
Loss of intrinsic factor produced in the gastric fundus, impaired iron absorption, and a deficiency of the fat-soluble vitamins present lifelong risks after RYGB and other mal­absorptive bariatric procedures. Vitamin replacement and nutritional monitoring are therefore mandatory in bariatric patients. (See Schwartz 11th ed., pp. 1191–1192.)
CHAPTER 28
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Small Intestine
1. How long is the small intestine? A. 4 to 6 ft B. 10 to 12 ft C. 4 to 6 m D. 10 to 12 m
2. Which of the following features is characteristic of the ileum, as opposed to the jejunum? A. The presence of valvulae conniventes B. The presence of Peyer patches C. Larger vasa recta D. Less fatty mesentery
3. A pocket- or sock-like outpouching on the anti­mesenteric side of the distal ileum, called a Meckel diver­ticulum, is caused by: A. Excessive traction on the intestine during childbirth. B. Increased intraluminal pressure. C. A persistent vitelline duct. D. A mutation of the c-Mec gene.
4. The most common presentations of symptomatic Meckel diverticuli include all of the following EXCEPT: A. Bleeding. B. Intestinal obstruction. C. Inguinal pain. D. Diverticulitis.
Answer: C
The small intestine’s length varies depending on whether radiologic, surgical, or autopsy measurements are made, but it is thought to measure 4 to 6 m in living subjects. (See Schwartz 11th ed., p. 1219.)
Answer: B
The entire small intestine contains valvulae conniventes, also known as plicae circularis. The jejunum has larger vasa recta, a larger diameter, and a less fatty mesentery. The ileum contains prominent lymphoid follicles called Peyer patches. (See Schwartz 11th ed., p. 1220.)
Answer: C
The embryonic gut communicates with the yolk sac by mean of the vitelline duct. Failure of this structure to obliterate by the end of gestation can result in a Meckel diverticulum. (See Schwartz 11th ed., pp. 1246–1247.)
Answer: C
Bleeding, intestinal obstruction, and diverticulitis are the most common presenting symptoms of Meckel diverticuli. Most are discovered incidentally at surgical procedures. Inguinal pain is not a typical symptom. (See Schwartz 11th ed., p. 1247.)
5. How much fluid normally enters the adult small intes­tine each day? A. 2 L B. 4 L C. 6 L D. 8 L
Answer: D
About 8 to 9 L of fluid enters the small intestine daily, of which over 80% is absorbed. This includes 2 L from oral intake, 1.5 L of saliva, 2.5 L of gastric juice, 1.5 L of bilio­pancreatic secretions, and 1 L of fluid secreted by the small intestine. (See Schwartz 11th ed., p. 1222.)
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6. How are the digestion products of carbohydrates, such as glucose, galactose, and fructose, absorbed through the intestine? A. By passive diffusion across enterocyte plasma
membranes
B. By facilitated diffusion via specific transporters such
as SGLT1, GLUT2, and GLUT5
C. By endocytosis of enterocytes on the villus
CHAPTER 28
Small Intestine
D. By facilitated diffusion through tight junctions
between enterocytes
7. What does the “enterohepatic circulation” refer to? A. The superior mesenteric—portal venous circuit B. The secretion of cholesterol in the bile and its reab-
sorption in the distal ileum
C. The secretion of bile acids by the liver and their reab-
sorption in the distal ileum
D. The secretion of cholecystokinin by the jejunum and
its stimulation of bile flow
8. Components of the gut-associated lymphoid tissue (GALT) include all of the following EXCEPT: A. Plasma cells. B. Stellate cells. C. Dendritic cells. D. CD4+ and CD8+ T cells.
Answer: B
The three terminal products of carbohydrate digestion are transported through the enterocyte brush border membrane via facilitative transporter proteins such as the sodium­glucose co-transporter 1 (SGLT1), glucose transporter 2 (GLUT2) and glucose transporter 5 (GLUT5). There is evidence of overexpression of these transporters, particu­larly SGLT1, in diabetes and obesity, and new therapeutic approaches for these conditions are designed to inhibit these transporters. (See Schwartz 11th ed., p. 1223.)
Answer: C
Bile acids act as detergents which increase the solubility of lipid micelles which are taken up by the brush border membrane of the jejunum, where >90% of fat is absorbed. The bile acids themselves remain in the intestinal lumen and are reabsorbed in the distal ileum where they enter the portal venous circulation and are resecreted in the bile. (See Schwartz 11th ed., p. 1225.)
Answer: B
The GALT includes Peyer patches, which are microscopic aggregates of B-cell follicles and intervening T-cell areas found in the lamina propria of the small intestine, primar­ily in the distal ileum. IgA-producing plasma cells and den­dritic cells populate these regions and serve to protect against microbes and foreign pathogens. Stellate cells, which produce collagen when activated, are not contained within the GALT. (See Schwartz 11th ed., p. 1226.)
9. The radiologic evaluation of a suspected small bowel obstruction may require use of a contrast agent to con­firm the location and possible etiology of the obstruc­tion. Water-soluble contrast agents, such as gastrograffin, are preferable to barium for all of the following reasons EXCEPT: A. Gastrograffin is safer than barium if a perforation has
occurred.
B. Gastrograffin may facilitate the resolution of a partial
small bowel obstruction.
C. Gastrograffin small bowel studies are easier to
perform.
D. Gastrograffin may detect subtle mucosal abnormali-
ties more sensitively than barium.
10. A closed loop obstruction is particularly dangerous because: A. Intraluminal pressure rises high enough to cause
ischemia and necrosis. B. The obstruction is painless. C. Bacterial overgrowth results in sepsis. D. The obstructive segment is not apparent on imaging
studies.
Answer: C
Water-soluble contrast agents, such as gastrograffin, are less likely to provoke peritonitis if a perforation has occurred and may be more sensitive in the detection of mucosal abnormali­ties. Gastrograffin has also been shown to be therapeutic for the treatment of partial small bowel obstruction, but gastro­graffin studies take longer and are more labor-intensive to perform. (See Schwartz 11th ed., pp. 1229–1231.)
Answer: A
A closed loop obstruction, in which an intestinal segment is obstructed both proximally and distally, as in a volvulus, is particularly dangerous because intraluminal pressure rises quickly and can cause venous congestion and arterial obstruc­tion which leads to necrosis of the intestinal wall and perfo­ration. It classically presents with “pain out of proportion to the physical exam,” and is usually apparent on CT scan which frequently shows a U-shaped or C- shaped dilated bowel loop associated with a radial distribution of mesenteric vessels converging toward a torsion point. (See Schwartz 11th ed., p. 1229.)
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11. Therapy of a small bowel obstruction usually consists of prompt surgical correction. In patients with no evidence of closed loop obstruction, and in whom there is no fever or leukocytosis or tachycardia, a period of careful obser­vation with nasogastric decompression may be success­ful in all of the following conditions EXCEPT: A. Partial small bowel obstruction. B. Obstruction in the early postoperative period. C. Obstruction due to Crohn disease. D. Obstruction due to an internal hernia.
12. Laparoscopic surgery for bowel obstruction may be pref­erable to open surgery for all of the following reasons EXCEPT: A. Laparoscopic surgery is associated with fewer wound
infections and a shorter length of hospital stay.
B. Laparoscopic surgery is preferable in cases where a
single adhesive band is causing the obstruction.
C. Laparoscopic surgery is less likely to produce fur-
ther adhesion formation which may cause recurrent obstruction.
D. The risk of iatrogenic bowel injury is higher with
laparoscopic surgery.
13. Crohn’s disease affects the small intestine in 80% of cases, and the colon alone in 20%. Isolated perineal and anorectal disease occurs in 5% to 10% of patients. In addi­tion, extraintestinal manifestations of Crohn’s disease occur in up to 25% of patients and may include which of the following? A. Erythema nodosum B. Interstitial lung disease C. Nephrolithiasis D. All of the above
Answer: D
Partial small bowel obstruction and early postoperative obstruction can mimic ileus and may respond to nonop­erative therapy. Crohn disease usually responds to medical therapy, although recurrent obstruction is an indication for surgical correction. Obstruction due to an internal hernia requires prompt surgical intervention to avoid strangulation and necrosis. (See Schwartz 11th ed., p. 1231.)
Answer: D
The use of laparoscopic surgery for small bowel obstruction has been found to be highly successful when the obstruction is caused by a single adhesive band. The avoidance of an open procedure also reduces the risk of subsequent adhesion for­mation. The morbidity risks of laparoscopic surgery are less than with open surgery and the risk of iatrogenic injury to the bowel is similar. (See Schwartz 11th ed., p. 1232.)
Answer: D
Extraintestinal manifestations of Crohn’s disease are diffuse and can involve dermatologic, rheumatologic, ocular, hepa­tobiliary, urologic, and pulmonary conditions. (See Schwartz 11th ed., p. 1237.)
CHAPTER 28
Small Intestine
14. The primary genetic defect associated with Crohn’s dis­ease is a mutation of the NOD2 gene on chromosome 16. This gene encodes for a protein product which: A. Mediates the innate immune response to microbial
pathogens. B. Activates stellate cells to produce collagen. C. Regulates the rate of crypt-to-villus enterocyte
migration. D. Mediates the production of enterocyte alkaline
phosphatase.
15. In the resection of a stenotic area of intestine in a patient with Crohn’s disease, the best approach is: A. A resection margin of 2 cm from gross disease. B. A resection margin of 12 cm from gross disease. C. A resection margin of 2 cm from microscopic disease
on frozen section.
D. A resection margin of 12 cm from microscopic
disease on frozen section.
Answer: A
The protein product of the NOD2 gene mediates the innate immune response to microbial pathogens. A variety of defects in immune regulatory mechanisms such as over responsive­ness of mucosal T cells to enteric flora-derived antigens can lead to defective immune tolerance and sustained inflamma­tion. (See Schwartz 11th ed., p. 1236.)
Answer: A
There are no differences in the recurrence rates for resection with a 2 cm margin or a 12 cm margin from gross disease. The additional bowel lost may contribute to eventual short gut syndrome in a patient who requires multiple resections, so minimizing bowel loss is a priority. There is no benefit to achieving frozen section negative margins in the resection of Crohn’s strictures; positive margin resections have the same recurrence rate as negative margin resections. The effort to obtain a frozen section negative margin carries the risk of removing more intestine than is necessary. (See Schwartz 11th ed., p. 1239.)
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