Small Bowel Flashcards

Question

The small intestine typically reabsorbs what percentage of the fluid that passes through its lumen? ``` A. 10 B. 20 C. 40 D. 50 E. 80 ```

Answer 1

ANSWER: E COMMENTS: The intestine has a remarkable ability to absorb and secrete large quantities of fluid. Absorption of water is a net result of fluxes into and out of the intestinal lumen. An average person consumes approximately 1 to 1.5 liters (L) of water per day. The gastrointestinal tract (GI) secretes an additional 5 to 10 L, including 1 to 2 L of saliva, 2 to 3 L of gastric secretions, 0.5 L of biliary secretions, 1 to 2 L of pancreatic juice, and 1 L of intestinal secretions. The small intestine reabsorbs nearly 80% of the fluid that passes through it. A rapid bidirectional movement of fluid in the intestinal lumen accomplishes this dynamic process. A total of 6 to 11 L of water enters the duodenum every day, but only 1 to 1.5 L arrives in the colon. Alterations in this fine balance caused by either impaired absorption or augmented secretion can result in overall net secretion of water and result in diarrhea.

Answer 2

ANSWER: D COMMENTS: The daily output from an established ileostomy is typically 500 to 1000 mL. Although there is a great deal of variation in daily output among individuals, the output in a given patient varies only about 20% with changes in diet or with episodes of gastroenteritis. The usual ileostomy sodium concentration is 115 mEq/L, although the concentration rises and falls with changes in total body sodium. With dehydration, the sodium concentration falls and the potassium level rises as a result of the ability of the terminal ileum to conserve sodium in times of salt depletion. Normally, the sodium-to-potassium ratio is about 12:1. The microbiologic flora of ileostomy output is markedly different from that of normal ileal fluid. The total number of bacteria is 80 times greater, and there is a 100-fold increase in the number of aerobes, a 2500- fold increase in the number of coliform bacteria, and an increase in the total number of anaerobes.

Answer 3

ANSWER: B COMMENTS: In healthy humans, the transit time of barium contrast from the duodenum to the terminal ileum varies greatly, from 30 min to 5 h. The average (>80%) transit time is approximately 1 h. However, the composition of the meal affects the rate of occur- rence and propagation of contractions during the postprandial period. The frequency of contraction is greatest with meals containing glucose and least after meals high in fat. Therefore transit is regulated to optimize absorption of nutrients.

Answer 4

ANSWER: E COMMENTS: MMCs are sets of propagated aboral peristaltic contractions occurring at 90-min intervals during fasting. They are one of the most recognizable and reproducible GI motility activities. The activity fronts of MMCs usually originate high in the stomach, propagate distally, and end in the ileum, usually at the mid-ileal level. Oral feeding inhibits MMCs and results in irregular, nonpropagating contractions throughout most of the small intestine. This postprandial inhibition generally persists for 3 to 4 h after a meal and is most pronounced with lipids. Although this motility pattern appears to be disorganized, there is a distal progression of chyme. Absorption is not affected by intestinal motility. Enteral feedings can therefore be used safely and efficiently in postoperative patients in whom motility may be altered. Both gastric and small bowel motility can be affected by exogenous conditions. The small bowel is less sensitive than the stomach to general anesthesia and laparotomy, each of which decreases the frequency of MMCs. The frequency of MMCs returns to normal within 6 to 24 h in the absence of peritonitis or abscess formation. The tone of the stomach is affected more than that of the small bowel by general anesthesia and laparotomy and may take longer than 24 h to normalize. This may explain the occurrence of postoperative nausea and emesis. Vagotomy-induced diarrhea is a result of persistence of the sustained, organized wave of MMCs during the postprandial state due to loss of vagal parasympathetic inhibition of MMCs. Segmental small bowel resection or denervation temporarily reduces the frequency of MMCs with a resultant temporary impairment of motility. Resection or denervation does not produce long- term sequelae provided that intestinal length is sufficient.

Answer 5

ANSWER: C COMMENTS: The extraintestinal manifestations of Crohn’s disease are listed in Table 22A.1. They are not a primary indication for surgery in most patients with this disease. Indications for surgery include obstruction, perforation, abscesses, internal or cutaneous fistulas, and perianal disease. However, if the involved bowel were resected, most extraintestinal manifestations would improve except for ankylosing spondylitis and hepatic changes. Surgery is not held to be curative in Crohn’s disease since it is a systemic disorder. Surgery is indicated when medical therapy fails or when the side effects of medications (such as steroids) are significant. Bowel-conserving approaches are important since the majority of patients will require multiple surgeries in their lifetime. Resection is limited to the offending segment(s). If adjacent areas of bowel are affected but are not the cause of perforation, obstruction, or fistula formation, they should be spared and managed medically. Obstruction due to fibrotic stricturing is the most common indication for abdominal surgery in patients with Crohn’s disease. Options for obstructed segments of the bowel include segmental resection and primary anastomosis or ostomy, stricturoplasty, and, rarely, bypass procedures. Repeated wide resections of small bowel may lead to a short gut syndrome. Stricturoplasty is beneficial in patients with multiple short areas of narrowing separated by normal intestine. Perforation occurs in 15%–20% of patients and usually results in the formation of a contained abscess, phlegmon, or an internal fistula to the bowel, bladder, or vagina. Enterocutaneous fistulas rarely occur in patients without previous operation, but they are common after surgery. Free perforations into the peritoneal cavity with peritonitis are rare. Anemia is common, but frank hemorrhage is rare. It may occur if an ulcer erodes into a large blood vessel. Anorectal disease occurs in 50% of patients with Crohn’s disease and may be the presenting problem in 5% of patients. Perirectal abscesses and/or fistulas develop in up to 30% of patients with Crohn’s disease of the small bowel and are separate from the diseased segment of small bowel. Patients with Crohn’s disease have an increased risk for the development of cancer in comparison with the general population, but the risk for colon cancer does not approach the level seen in patients with chronic ulcerative colitis. This difference may be related to the segmental nature of Crohn’s disease involving a smaller proportion of the colon and the shorter average period between diagnosis and colectomy in Crohn’s disease. The risk, however, is not considered high enough to warrant prophylactic resection. However, colonoscopic surveillance is indicated. Most cases of small bowel cancer associated with Crohn’s disease occur in patients with long-standing disease and are most commonly found in a previously bypassed segment of bowel or at the site of a chronic small bowel stricture.

Answer 6

ANSWER: C COMMENTS: Proximal and distal margins of resection are determined by gross visual examination and palpation to soft pliable tissue. Frozen sections should not be routinely performed. Resecting to areas without microscopic evidence of inflammation does not reduce recurrence rates or decrease complications such as leaks and may lead to unnecessary loss of small bowel length. All areas of significant stricturing must be addressed during the operation since leaving any will often result in rapid recurrence of symptoms and the need for additional surgery. Bowel resection for strictures is the most common abdominal procedure performed in Crohn’s disease; however, stricturoplasty is preferred for short obstructing segments since no normal bowel is sacrificed at the margins. The length of a stricture acceptable for stricturoplasty is debatable. Different surgeons have advocated for various types of stricturoplasty to manage longer segments. However, the commonly accepted approach is to perform the now standard Heineke– Mikulicz type of stricturoplasty for strictures up to 3 to 4 cm long. There is no defined limit for the number of strictures that can be treated during one operation; some studies have shown up to 19 stricturoplasties done at once without increased morbidity. Remarkably, there is a low leak rate, and the disease at these sites usually resolves.

Answer 7

ANSWER: E COMMENTS: Several microscopic features characterize but are not specific for Crohn’s disease. These features progress from an early to a late phase of involvement and can be described as a granulomatous fibrotic inflammation progressing through all layers of the bowel wall. In the early phase, edema of the entire bowel wall is seen, accompanied by lymphangiectasia and hyperemia and an increased proportion of goblet cells in an otherwise normal mucosa. In the intermediate phase, thickening is caused by fibrosis of the submucosal and subserosal areas of the bowel. Focal mucosal ulcers become numerous, and in 60% of patients, sarcoid-like granulomas appear, particularly in the submucosa, subserosa, and regional lymph nodes. These granulomas contain epithelioid giant cells, do not caseate, and do not contain acid-fast bacilli. The absence of granulomas does not exclude the diagnosis of Crohn’s disease. Lymphangiectasia remains visible throughout the interme- diate and late phases. In the late phase, the dense fibrosis exceeds that expected from the simple healing of an inflammatory insult and produces a fixed stenosis and partial obstruction of the lumen. The mucosa is denuded over wide areas, with occasional islands of intact mucosal cells (pseudopolyps). Glands deep in the mucosa resemble those of the pyloric region and are termed aberrant pyloric glands or Brunner gland metaplasia. The ulcers can be deep, and progression through the bowel wall may result in abscess and/or fistula formation.

Answer 8

ANSWER: C COMMENTS: Only 10% of patients with Crohn’s disease are initially seen in an acute stage, usually with symptoms similar to those of appendicitis. In most patients, the onset is insidious, with intermittent pain or discomfort being the most frequent and sometimes the only symptom. The pain is often precipitated by a dietary indiscretion. With advanced disease, the pain may become associ- ated with signs and symptoms of partial obstruction. Symptoms worsen with eating, and many patients resort to a liquid diet. Constant, localized pain, especially if associated with a palpable mass, suggests the presence of a phlegmon, abscess, or enteric fistula. Diarrhea is the next most frequent symptom, and, unlike diarrhea in patients with chronic ulcerative colitis, it rarely contains mucus, pus, or blood. Diarrhea is the result of several factors. The inflamed segment of small bowel has a decreased capacity to absorb intestinal contents. In addition, the obstruction produced by this involved segment alters the absorptive capacity of the proximal part of the bowel. Decreased absorption of bile salts in the diseased terminal ileum leads to bile salt–induced damage to the absorptive cells of the colonic mucosa and produces choleretic diarrhea. One-third of patients initially have a fever, and about 50% experience weight loss, weakness, and fatigue. Although the diarrhea is usually not bloody, persistent occult loss of blood frequently produces iron deficiency anemia, which may be aggravated by the deficiency of vitamin B12, which is absorbed in the terminal ileum. Hypoproteinemia occurs because of increased loss of protein from the inflamed bowel mucosa. Vitamin and mineral deficiencies are the results of decreased ingestion, altered metabolism, and decreased absorption.

Answer 9

ANSWER: E COMMENTS: The use of steroids in patients with an acute flare of Crohn’s colitis or ulcerative colitis during pregnancy has been shown to be not only effective but also safe for the mother and fetus. This is also true of sulfasalazine. Corticosteroids have never been shown to maintain remission of Crohn’s colitis or ulcerative colitis, and prolonged use often results in major side effects. Sulfasalazine and other 5-acetylsalicylic acid (5-ASA) products including mesalamine and coated 5-ASA compounds are effective in maintaining remission only in patients with ulcerative colitis. Topical steroids in foam or enema preparations may be absorbed in small amounts (10%–20%). Alternate-day dosing has not been effective in patients with inflammatory bowel disease. Intravenous ACTH is preferred instead of intravenous hydrocortisone by some, but controversy still exists regarding whether ACTH is more effective, even for previously untreated ulcerative colitis. An ACTH dose of 40 to 60 units over an 8-h period appears to be as effective as 300 to 400 mg/day of hydrocortisone. ACTH use has waned in the face of newer medical therapies. The duration of steroid therapy varies depending on the severity of the disease, but it should always be tapered on an individual basis with the goal of discontinuation. Although some patients (10%–15%) are kept on a low maintenance dose when complete elimination leads to flare-up, steroid therapy should not be continued as maintenance in patients who have achieved complete remission. Failure to achieve remission after 2 months of administering more than 15 mg of prednisone may be an indication for surgical management.

Answer 10

ANSWER: A COMMENTS: The most likely etiology of diarrhea in this patient is malabsorption of bile salts. Bile salts and vitamin B12 are absorbed in the terminal ileum. After resection of the terminal ileum, bile salt reabsorption may be compromised and it enters the colon in much higher concentrations than normal. Bile salts irritate the colonic mucosa and interfere with absorption of fluid and electrolytes, leading to increased frequency and watery stools. Treatment for bile salt–induced diarrhea is oral cholestyramine, a bile salt–binding resin. Reactivation of Crohn’s disease is common following surgery. Rates vary from 28% to 73% at 1 year and from 77% to 85% at 3 years after ileal resection. The lowest rates of recurrence are in patients with disease limited to the colon after total colectomy (20%). Endoscopic recurrence rates are higher than symptomatic recurrence rates. Most colonic and terminal ileal recurrences may be seen with colonoscopy. Bacterial overgrowth is more frequently associated with a nonfunctioning portion of bowel that leads to stasis. Examples include dilated proximal bowel above a stenotic obstruction, intes- tinal diverticula, and diversion or bypass surgery. Bacteria consume vitamins and nutrients. Symptoms include nausea, vomiting, bloat- ing, and diarrhea. The diagnosis is made with an abnormal d-xylose breath test. Symptoms generally improve with antibiotics, although repeated courses or maintenance may be needed if the situation is not surgically corrected. Gastric acid hypersecretion is associated with short gut syndrome. Short gut syndrome will most likely occur in patients with less than 100 cm bowel and no ileocecal valve or in those with less than 50 cm bowel and an ileocecal valve. This patient has had approximately 90 cm of bowel removed, leaving behind enough bowel that short gut syndrome is unlikely.

Answer 11

ANSWER: B COMMENTS: TPN has no role as a primary therapy for ulcerative colitis, but it may help maintain a satisfactory nutritional state during bowel rest. TPN does not prevent the need for colectomy in refractory cases. The role of TPN in patients with Crohn’s colitis is not well established, but in those with Crohn’s colitis and small bowel involvement, TPN may improve remission rates and promote fistula closure. Elemental diets have been sporadically shown by some to be effective in inducing remission of active Crohn’s disease. The patient’s tolerance may be poor, however, and the results are not superior to those obtained with corticosteroids and sulfasalazine. Peripheral parenteral alimentation (PPN) rarely provides adequate caloric replacement and may induce venous sclerosis and phlebitis. Enteral nutrition is preferable to TPN, when possible, since complications are much lower and nutritional balance is better. Nutrition delivered through the GI tract appears to preserve normal GI function, benefit normal immune function, and decrease systemic inflammation.

Answer 12

ANSWER: C COMMENTS: Stricturoplasty for Crohn’s disease was first per- formed in 1981 by Emanuel Lee based on his experience with patients with intestinal tuberculosis in India. The procedure was popularized by Victor Fazio and his colleagues at the Cleveland Clinic. Experience since then has shown it to be a safe alternative to resection in properly selected patients. Stricturoplasty should be considered in any patient who has had extensive previous resections of diseased bowel and in whom further resection might create short bowel syndrome (SBS) and in those with multiple separated fibrotic small bowel strictures. Many strictures can be treated safely by a single laparotomy. The entire small bowel must be inspected to avoid overlooking strictures that are not obvious. This can be accomplished by passing a long intestinal tube through one of the stricturoplasty sites. The catheter is passed both proximally and distally through the entire length of small bowel. The balloon on the catheter is inflated to 2 cm, and then the catheter is gradually withdrawn, identifying all significant strictures that are marked with a suture. A longitudinal incision is made over the stricture and extended for 2 cm proximally and distally beyond the stricture. A biopsy is performed to rule out neoplasia. The enterotomy is then closed transversely with a single layer of interrupted absorbable sutures. The site is marked with a metal clip. If a single stricture or several strictures close together are encountered at a patient’s first surgery, resection rather than stricturoplasty is preferable because it eliminates the diseased bowel and establishes the diagnosis. Patients treated by stricturoplasty have been compared with patients treated by resection. The need for reoperation at the original site is similar. Postoperative complications are infrequent. At the Cleveland Clinic, anastomotic leakage, abscesses, or fistulas have occurred in 9% of patients treated by stricturoplasty. Restricture at the stricturoplasty site occurred in only 2%.

Answer 13

ANSWER: C COMMENTS: Intussusception is the telescoping of one portion of an intestinal segment onto the lumen of an adjacent segment (Fig. 22A.2). It is commonly seen in children. The lead point is commonly a Meckel’s diverticulum or ileal lymphoid hyperplasia. It is the most frequent cause of pediatric bowel obstruction. It is rare in adults, in whom it accounts for less than 5% of cases of bowel obstruction. Most cases of intussusception in adults are caused by a specific lead point, whereas only 8%–20% are idiopathic. Causes of intussusception in adults include inflammatory bowel disease, adhesions, Meckel’s diverticulum, neoplasms including cancers and polyps such as those in Peutz-Jeghers syndrome (PJS), and intestinal tubes. A barium enema is useful for intussusception in children because it is diagnostic and therapeutic. Barium enemas and pneumatic decompression are often effective at reduction of the intussusception. However, these approaches are not useful in adults. Surgery is the mainstay for symptomatic adult intussusception. A formal bowel resection with oncologic principles is warranted when malignancy is suspected, such as in this patient with a history of melanoma. Melanoma is the most common nonabdominal malignancy to metastasize to the small intestine.

Answer 14

ANSWER: B COMMENTS: PJS is an autosomal dominant familial disease characterized by intestinal polyposis and mucocutaneous hyper- pigmentation. The polyps are hamartomas that are most frequently located in the jejunum and ileum, but they can also be found in the stomach, duodenum, colon, and rectum. It is generally believed that their malignant potential is fairly low. PJS can cause intussusception or hemorrhage. Up to one-third of patients initially have abdominal pain and a palpable mass. Symptoms may be self-limited as the intussusception comes and goes. The diagnosis of intestinal polyps may be made with UGI and small bowel follow-through contrast studies, pill endoscopy, or at the time of surgery. Magnetic resonance (MR) enterography may prove to be useful as this modality becomes more refined. Surgery is indicated for persistent obstruction, frequent recurrences, or bleeding. Surgical treatment is limited to conservative resection of the polyps through enterotomies or limited resection. Only larger or intussuscepting polyps need to be removed. Intraoperative total endoscopy is the most accurate method of polyp identification.

Answer 15

ANSWER: C COMMENTS: Peritoneal adhesions account for more than 50% of cases of small bowel obstruction in the United States. Obstruction immediately after abdominal operations, however, is uncommon, occurring among only 1% of patients in the 4 weeks after laparotomy. Hernias of all types are second only to adhesions as the most frequent cause of obstruction. External hernias such as inguinal or femoral hernias can present with symptoms of obstruction. Femoral hernias are particularly prone to incarceration and bowel necrosis because of the small size of the hernia inlet. An important consideration is Richter hernia. In this variant, only a portion of the bowel wall is incarcerated. Richter hernia most frequently occurs in association with femoral or inguinal hernia. Yet complete obstruction can occur if more than one-half to two-thirds of the bowel circumference is incarcerated. Approximately 5% of cases of intussusception occur among adults. Intussusception occurs when one segment of bowel telescopes into an adjacent segment. The result is obstruction and ischemic injury to the intussuscepting segment. Of adult cases of intussusception, 90% are associated with pathologic processes. Tumors, benign and malignant, can act as a lead point causing the intussusception in more than 65% of cases among adults.

Answer 16

ANSWER: A COMMENTS: The term “ileus” reflects underlying alterations in motility of the gastrointestinal tract that lead to functional (not mechanical) obstruction. Differentiating normal POI and the prolonged course of paralytic ileus is based primarily on the time since operation and the clinical circumstances. Besides the location of the previous operation (upper abdominal, lower abdominal, pelvic), the nature of the previous operation and the findings may contribute. Peritonitis or spillage of noxious material delays the return of normal bowel function. Differentiating paralytic ileus from mechanical obstruction often is difficult. Abdominal radiographs will reveal gas in segments of both the small and large bowels in POI. Occasionally, UGI contrast radiography or CT can be helpful in discriminating the cause. Early postoperative obstruction is uncommon and is particularly rare for upper abdominal surgery. Most cases occur after operations on the colon, particularly abdominoperineal resection. There has been little success in the use of active prokinetic agents, such as metoclopramide, to shorten recovery times after lower abdominal pro- cedures; however, alvimopan has been shown to significantly decrease the incidence of POI. Alvimopan competitively binds to mu-opioid receptors on the bowel. If given prior to the use of narcotics, it reduces the motility-slowing effects of these commonly used medications. Thus recovery after POI can take longer with the use of intravenous narcotics than with epidural pain control. Enhanced recovery after surgery protocols commonly include the use of alvimopan starting before surgery, epidurals, nonnarcotic pain medications, and regional blocks for pain control and may demonstrate improvement in time-to-recovery of bowel function.

Answer 17

ANSWER: C COMMENTS: Timing an operation for a small bowel obstruction requires considerable clinical judgment. The duration of initial resuscitation must be balanced against the need to prevent gangrene by prompt intervention. Severe intravascular volume depletion can occur as a result of fluid sequestration (as much as 6 L) in the lumen of the bowel and peritoneal cavity. Sodium, chloride, and potassium depletion frequently accompanies bowel obstruction. Blood loss is unusual unless strangulation is present. Before induction of general anesthesia, fluid and electrolyte replacement should be instituted with isotonic saline solution to normalize the heart rate, blood pressure, and urine output. Potassium repletion should begin once adequate urine output is established. Surgery is delayed until the patient is stabilized. Nasogastric decompression is an important component of supportive therapy; nausea and vomiting are controlled by this measure, and the risk for aspiration is reduced. Swallowed air is evacuated, thus further limiting intestinal distention. In patients with adhesive partial bowel obstruction and no signs of strangulation (i.e., fever, tachycardia, localized abdominal pain, or leukocytosis), a 24- to 48-h period of bowel rest and nasogastric decompression is warranted. Most patients with a partial obstruction will resolve spontaneously with the above measures. Delay in surgical intervention for a complete small bowel obstruction is not recommended (beyond 1 to 2 days) because the likelihood of strangulation and ischemia increases and is higher than with partial bowel obstruction. There is no increase in the anastomotic leakage rate of small bowel anastomoses in urgent versus elective small bowel resections, provided that the segment of bowel used for the anastomosis is healthy and not overly distended. Therefore a proximal stoma and mucous fistula are seldom necessary following uncomplicated small bowel resection for obstruction.

Answer 18

ANSWER: D COMMENTS: This patient has gallstone ileus. Gallstone ileus accounts for only 1% of all intestinal obstructions but is widely discussed. It is caused by the passage of a large stone through a biliary– enteric fistula (commonly the duodenum) thus producing a bowel obstruction. Thus the name “gallstone ileus” is a misnomer since it is a true obstruction and not an ileus. The most common site of obstruction in patients with gallstone ileus is the terminal ileum because of the narrow lumen at the ileocecal junction. The most common manifestations of gallstone ileus are nausea, vomiting, and abdominal pain. About 50% of patients will have gallbladder-related symptoms. Plain abdominal radiographs can reveal pneumobilia, dilated loops of small bowel, and a calcified stone outside the gallbladder. Gallstone ileus is treated surgically. Obstruction is relieved by milking the stone in a retrograde fashion and removing it through a proximal enterotomy. The segment of bowel at the site of impac- tion should be inspected for evidence of ischemia and necrosis. If an ischemic compromise has occurred, the ischemic bowel should be resected. Takedown of the biliary–enteric fistula and cholecystectomy may be done during the initial laparotomy. However, in patients who are not able to tolerate a prolonged operation, this may be deferred. Although many surgeons recommend cholecystectomy and fistula repair at some point, it is not clear that this is absolutely necessary, particularly in elderly or infirm patients.

Answer 19

ANSWER: A COMMENTS: See Question 20.

Answer 20

ANSWER: A COMMENTS: A Meckel’s diverticulum, the most frequently encountered diverticulum involving the small intestine, occurs in 2%–4% of the general population. It is a true diverticulum containing all layers of the bowel wall and arises from the antimesenteric border of the ileum, 50 to 75 cm from the ileocecal valve. The diverticulum is a result of abnormal regression of the embryonic vitelline duct. Frequently, there is a persistent band of tissue extending from the tip of the diverticulum to the umbilicus. The rule of 2’s states that it usually presents by the age of 2, is 2 feet from the ileocecal valve, occurs in 2% of the population, and may contain one of the 2 types of heterotopic mucosa. The diverticulum may contain ectopic gastric mucosa capable of producing peptic ulceration and bleeding in the adjacent ileal mucosa. This ectopic gastric mucosa can be visualized with 99mTc-labeled scans. Gastric tissue is the most common ectopic tissue and is found in 50% of these lesions. Pancreatic tissue is the next most common, although colonic mucosa has been found rarely. Clinical problems are most often seen in the young pediatric population. The most frequent complications are bleeding, intussusception, and obstruction. The latter is generally caused by vol- vulus or twisting around the persistent band. The least common complication is diverticulitis, which is clinically manifested as lower abdominal pain and is usually thought to be appendicitis on presentation. Therapy consists of diverticulectomy for uncomplicated diverticulitis, and segmental ileal resection for complicated diverticulitis or bleeding, since the ulcer is usually outside of the diverticulum. Prophylactic diverticulectomy for an incidentally found Meckel’s diverticulum is still somewhat controversial. Some clinicians recommend not removing the diverticulum when found incidentally unless there is evidence of ectopic gastric mucosa or the neck of the diverticulum is narrow. The rate of complication from a Meckel’s diverticulum is about 6.4% over a lifetime and becomes smaller as a person ages. Other clinicians argue that postoperative complications after prophylactic removal are rare, and they should be removed when found. In an otherwise uncomplicated procedure, particularly in a younger person, prophylactic diverticulectomy is reasonable.

Answer 21

ANSWER: E COMMENTS: Small bowel diverticula are not terribly uncommon and may be found in the duodenum in 3%–5% of individuals and in the jejunum and ileum in 1%–2% on radiographs, endoscopy, and autopsies. Most duodenal, jejunal, and ileal diverticula are asymptomatic and are found incidentally. Diverticula of the duode- num, jejunum, and ileum are most commonly false (pulsion) diverticula and lack muscularis propria. Duodenal diverticula are usually solitary and project medially toward the head of the pancreas. Although most are asymptomatic, 10% of patients may have nonspecific epigastric symptoms, such as pain and bloating. They also may bleed and perforate. In instances of contained perforation, the abscess should be drained. Gastrojejunostomy is the operation most often applicable, although biliary decompression is occasionally necessary when the duct is compressed. When there is bleeding without inflammation, diver- ticulectomy is indicated, either from a dorsal approach using the Kocher maneuver or via a duodenotomy. Jejunal and ileal diverticula are often multiple and project from the mesenteric border of the bowel into the leaves of the mesentery. This type of diverticulum is more common in the jejunum than in the ileum. Bacterial overgrowth may be treated with antibiotics. Bleeding and perforation are treated with segmental resection. Asymptomatic diverticula of the duodenum, jejunum, or ileum do not require therapy.

Answer 22

ANSWER: B COMMENTS: See Question 23.

Answer 23

ANSWER: B COMMENTS: The most frequent symptom of small bowel tumors is abdominal pain. Common benign lesions of the small intestine include gastrointestinal stromal tumors, adenoma, hemangioma, and lipoma. The most common benign small bowel tumor is an adenoma. The most common symptomatic small bowel tumors are GISTs. Symptoms associated with small bowel tumors are often vague and nonspecific such as anorexia, dyspepsia, and abdominal pain. Patients may also have signs of obstruction that are usually related to intussusception but may also be due to malignant narrowing. Occult bleeding is also a common initial symptom. When small bowel neoplasms are suspected, a barium small bowel follow-through study is indicated and is generally diagnostic. CT or MR enterography may also be useful. GISTs arise from the interstitial cells of Cajal. They express CD117 and CD34. These tumors grow intramurally and can cause obstruction. At times, these tumors can reach considerable size and outgrow their blood supply, which results in GI bleeding. Mitotic rates higher than 5 per 50 high-power fields increase the risk for recurrence. Lipomas are now included in the GIST category. There are three types of small bowel adenomas: tubular adenomas, villous adenomas, and Brunner gland adenomas (usually in the duodenum). Most of these lesions are asymptomatic and found incidentally at the time of autopsy. Adenomas present with bleeding or obstruction. Polypectomy may be performed in the duodenum if the tumor is histologically benign. Jejunal and ileal lesions are treated with segmental resection. Hamartomas of the small bowel are usually associated with PJS. Patients also have 1- to 2-mm pigmented lesions located in the circumoral region of the face, buccal mucosa, palms, soles, and perianal region. The most common initial symptom is a colicky abdominal pain, usually as a result of intermittent intussusception. Hemangiomas are malformations consisting of a submucosal proliferation of blood vessels. They can occur anywhere along the GI tract, with the jejunum being the most common small bowel segment involved. Bleeding is the most frequent symptom. Angiography and 99mTc-labeled red blood cell scanning are useful diagnostic studies. When identified, small bowel tumors should be excised because of the risk for complications, to establish the diagnosis, and to exclude cancer. Small lesions can be excised with an enterotomy and primary closure. Larger or suspicious lesions should be treated with segmental resection with primary anastomosis.

Answer 24

ANSWER: E COMMENTS: See Question 25.

Answer 25

ANSWER: C COMMENTS: Malignant tumors of the small bowel account for 2% of all GI malignancies. The most frequent primary type is adenocarcinoma, followed in decreasing frequency by carcinoid, GIST, and lymphoma. Although adenocarcinoma occurs with equal frequency in the duodenum, jejunum, and ileum, the other types tend to occur most often in the ileum. In contrast to benign lesions, malignant lesions of the small intestine are usually accompanied by pain and weight loss. Other clinical manifestations may include diarrhea, obstruction, or chronic blood loss with anemia. Obstruction from malignant lesions is usually because of tumor infiltration, stricturing, and adhesion. The preferred therapy is wide resection with regional lymphadenectomy. For each entity, survival is dependent on a number of factors and is variable, but in general, GISTs have a 5-year survival rate that ranges from 7% to 56%, lymphomas have a 5-year survival rate of about 40%, and adenocarcinoma has the lowest survival, at about 20%. Postoperative chemotherapy and radiation therapy can be useful in treating a patient with lymphoma but are not useful adjuncts for adenocarcinoma or sarcoma. Histiocytic lymphoma may develop in patients with long-standing celiac sprue and has a worse prognosis than do conventional small bowel lymphomas. The Mediterranean-type lymphoma, a variant associated with monoclonal alpha heavy chains and a dense plasma cell tumor infiltration, also carries a poor prognosis.

Answer 26

ANSWER: A COMMENTS: GISTs are the most common nonepithelial neoplasms of the small bowel. They originate from the interstitial cells of Cajal. GISTs are most common in the stomach (60%), followed by the small bowel (30%). On endoscopy, GISTs classically appear as submucosal lesions. The majority express the CD117 antigen of the KIT transmembrane receptor tyrosine kinase, which is the product of the KIT protooncogene. Mutation in KIT leads to abnormally activated KIT protein and enables oncogenic signaling in the cell. This discovery led to the development of systemic therapy with imatinib mesylate (Gleevec), which blocks KIT signaling and inhibits tumor proliferation. Postoperative imatinib has been shown to prolong recurrence-free survival and is considered standard fol- lowing resection of GIST tumors larger than 3 cm. The clinical behavior of GISTs is highly variable, but GISTs > 1 cm have increased malignant potential. Tumor size and mitotic rate are the two major criteria used to define aggressive behavior.

Answer 27

ANSWER: B COMMENTS: The origin of carcinoid tumors is the Kulchitsky cell, which is thought to arise from the neural crest. Carcinoids can occur anywhere in the GI tract. The most frequent site is the appendix, followed by the ileum and rectum. Extraintestinal sites include the bronchus and ovaries. Small bowel carcinoid tumors tend to be multiple in 30% of cases, and a second GI tumor of another histologic type can be found in 30% of patients. The prognosis is a function of the size of the tumor and its site of origin. Ileal carcinoids tend to metastasize more commonly than those that originate in the appendix. The usual submucosal location of carcinoid tumors often makes them difficult to find on radiographic examination or with cursory palpation during an exploratory laparotomy. The tumors may incite an intense fibrotic reaction in the surrounding soft tissue and mesentery, which can cause luminal narrowing. Mesenteric lymph node and liver metastases can be large in comparison with the primary tumor. Tumors less than 1 cm in diameter and without demonstrable metastases can be treated by excision or segmental resection. Those larger than 1 cm or with regional metastases should be excised widely along with lymph node clearance; right hemicolectomy is indicated for >1-cm lesions of the distal ileum and appendix. For patients with metastases (local or distant) and in whom carcinoid syndrome is present, removal of the primary tumor and debulking of metastatic disease can provide considerable palliation.

Answer 28

ANSWER: E COMMENTS: Episodic manifestations of carcinoid syndrome include flushing, diarrhea, and asthma. The cutaneous manifestations are the most common and consist of episodes of flushing of the face, neck, arms, and upper part of the trunk, occasionally accompanied by vasomotor collapse. Diarrhea is significant in more than 80% of patients and is usually sudden in onset, watery, and accompanied by cramping pain and borborygmi. Asthmatic attacks occur in 25% of patients. Manifestations of long-standing involvement include the development of facial hyperemia with telangiectasias on the cheeks, nose, and forehead; development of the cutaneous lesions of pella- gra; and valvular heart disease. The valves most commonly involved are the tricuspid and pulmonic, although the mitral and aortic valves are sometimes affected. Peripheral edema is present in about 70% of patients and can occur in the absence of valvular disease. Functioning carcinoid tumors divert up to 60% of dietary tryptophan into the production of serotonin, thereby contributing to the development of pellagra and protein deficiency. Serotonin is metabolized in the liver to 5-HIAA, which is excreted in urine. For this reason, the most useful diagnostic test in patients suspected of having a carcinoid tumor is the determination of 5-HIAA levels in a 24-h collection of urine. 5-HIAA is inactive and does not cause carcinoid syndrome. Carcinoid syndrome is produced by release of serotonin into the systemic circulation either by liver metastases or by tumors located outside the portal distribution. Although it is generally believed that patients with carcinoid syndrome have tumors that produce serotonin, the role of serotonin in the mediation of the syndrome is not clear. Not all patients with elevated production of serotonin have the syndrome. Some patients with the syndrome have normal levels of 5-HIAA in urine, and injection of pure serotonin does not create all of the manifestations of the disease. It is likely that carcinoid tumors have the capacity to produce a number of biologically active peptides, which accounts for the variability of the syndrome and discrepancies between a patient’s serotonin levels and the clinical findings. Other substances produced by carcinoid tumors include histamine, dopamine, kallikrein, substance P, prostaglandins, and neuropeptide K. Treatment of carcinoid crisis includes intravenous octreotide, intravenous antihistamine, and hydrocortisone.

Answer 29

ANSWER: D COMMENTS: See Question 30.

Answer 30

ANSWER: B COMMENTS: Treatment of small bowel carcinoid is based on tumor size and the presence or absence of metastatic disease. Segmental resection is adequate for tumors smaller than 1 cm without regional lymph node metastasis. Wide excision is indicated for lesions larger than 1 cm, multiple tumors, or regional lymph node metastasis. Right hemicolectomy is indicated for lesions of the terminal ileum or base of the appendix. Debulking is indicated for metastatic carcinoid tumors. This may involve liver resection. Hepatic artery ligation or percutaneous embolization has also produced good results in controlling the carcinoid symptoms produced by liver metastasis. Medical therapy for patients with malignant carcinoid is directed at relieving symptoms. Octreotide, a somatostatin analogue, helps relieve symptoms in most patients. Regression of tumor with the use of octreotide has been reported. Interferon-alfa has also been shown to relieve symptoms. Chemotherapeutic agents such as streptozotocin and 5-fluorouracil have had limited success in treating malignant carcinoid. They are used mostly in patients with metastatic disease who are symptomatic and unresponsive to other therapies.

Answer 31

ANSWER: B COMMENTS: Somatostatin was first identified in 1973. Since then, a great deal of interest has been directed at characterizing and identifying its physiologic effects and the clinical utility of somatostatin and its analogues. Somatostatin is a 14–amino acid protein with several analogues of shorter lengths that maintain clinical effectiveness. The general effects of somatostatin are those of an inhibitory hormone. Several provocative agents may be used before conducting tests for neuroendocrine tumors, including pentagastrin, secretin, and calcium infusion. Somatostatin is not effective as a provocative agent. Somatostatin receptor scintigraphy uses indium-111 and a gamma camera. This study has several advantages over conven- tional imaging (CT or MRI). Its sensitivity is higher (90% vs. 70%) for metastatic disease, it is more effective in identifying the primary tumor site, and it visualizes the entire body to detect occult metastases. Carcinoid tumors visible by somatostatin receptor scintigraphy suggest that these particular tumors have somatostatin receptors and are therefore subject to the inhibitory effects of somatostatin. Carcinoid crisis is a life-threatening event that may develop during episodes of flushing, anesthesia, or surgery. Severe hypotension and bronchospasm may occur during carcinoid crises, and they may be refractory to the usual supportive care. The reported incidence of such crises is variable and ranges from 2% to 50%. Somatostatin may be administered preoperatively as a prophylactic agent or during a carcinoid crisis as a therapeutic agent. It is usually successful in reversing the condition. Somatostatin has also been found to be highly effective in relieving the symptoms of carcinoid syndrome. It has been suggested that chronic octreotide therapy results in longer survival in patients with carcinoid syndrome than in those treated with chemo- therapy, but this hypothesis remains to be proven by randomized, controlled trials.

Answer 32

ANSWER: E COMMENTS: Metastatic tumors of the small bowel are more common than primary tumors. The most common metastases to the small bowel are primary tumors arising from other intra abdominal organs. In these cases, small bowel involvement occurs by either direct extension or implantation of tumor cells. Extra abdominal metastasis to the small bowel is rare. Cutaneous melanoma is the most common extra abdominal source of metastasis to the small bowel. Other extra abdominal sources include breast and lung cancers. Treatment is palliative resection or bypass if the metastatic tumor is not amenable to resection.

Answer 33

ANSWER: C COMMENTS: Most fistulas are iatrogenic and result from anas- tomotic leakage, inadvertent injury to the bowel during the opera- tion, laceration of the bowel during an abdominal closure, or retained foreign bodies. Less than 2% of fistulas are the result of diseased bowel. When they are, the most common contributing factors are preoperative radiation therapy, intestinal obstruction, and inflammatory bowel disease. Although small bowel fistulas occasionally lead to generalized peritonitis, they most commonly produce a walled-off abscess manifested as an infection of the operative incision. The initial drainage may be purulent, but if the infection is caused by anastomotic leakage of the small bowel, the drainage becomes enteric within 1 to 2 days.

Answer 34

ANSWER: D COMMENTS: The initial management of a small bowel fistula includes the administration of appropriate intravenous fluids, proximal decompression with nasogastric suction, control and quantification of the output of the fistula, and protection of the surrounding skin. Fistulas are classified according to their locations and the volumes of their output. Proximal fistulas tend to have higher output and lead to more severe electrolyte and fluid imbalances. Nasogastric suction can be helpful in diminishing the output of proximal intestinal fistulas, but the output of those more distal in the gut may not be influenced by this maneuver. Sump catheters can provide a means of controlling and quantifying high-output fistulas, especially early in their formation. Maintaining proper position of the catheter in the wound can be problematic. Once the fistula tract is established, suction catheters should be promptly replaced with a stoma appliance fixed to the edges of the fistula. Enteric contents are highly corrosive, and the skin surrounding the fistula opening should be protected carefully. Gauze dressings are generally ineffective at absorbing all the drainage and protecting the skin. Therefore their use is generally avoided. Most well- established fistulas do not produce sepsis, but in patients with persistent fever, systemic administration of antibiotics and a careful search for an undrained abdominal abscess are indicated. Early in the workup of this patient and before the GI tract has been filled with contrast material (from conventional GI radio- graphs), CT should be performed to look for areas of abscess for- mation or fluid accumulation. It may also identify the site of the fistula. If CT does not show the site, fistulography is helpful. If one is concerned about distal obstruction, a small bowel follow-through study may provide information, if this issue was not satisfactorily answered by CT or fistulography.

Answer 35

ANSWER: E COMMENTS: Knowing the location of the fistula is of important prognostic and therapeutic value. The overall mortality rate for small bowel fistulas is 20%; the rate is higher for jejunal fistulas and lower for those of the ileum. With proper supportive care, such as intravenous or enteral alimentation, and in the absence of distal obstruction, up to 40% of small bowel fistulas close spontaneously. Enteral alimentation has the advantage of avoiding the possible hepatic and septic complications associated with pro- longed TPN. Even if there is a slight increase in fistula output after the start of enteral nutrition, the fistula may still close. Fistulas of the proximal jejunum may require transnasal insertion of a long tube through the stomach and duodenum and just beyond the fistula before starting enteral alimentation. Surgery should be avoided for 4 to 6 weeks to permit spontaneous closure and allow the local inflammation to subside, thereby facilitating subsequent surgery. The preferred operation for correcting a persistent fistula is resection of the fistula in continuity with the segment of involved bowel, followed by primary anastomosis. Alternative therapies include complete or partial exclusion with primary anastomosis.

Answer 36

ANSWER: C COMMENTS: The blind loop syndrome is caused by stasis of the intestinal contents with subsequent bacterial overgrowth. This stasis can be caused by a number of abnormalities, including stricture, stenosis, fistula, diverticulum, or the formation of a blind pouch (as noted in a Billroth II operation). Steatorrhea, diarrhea, anemia, weight loss, abdominal pain, multiple vitamin deficiencies, joint pains, and occasionally neurologic disorders characterize the syndrome. The steatorrhea is the result of bile salt deconjugation in the stagnant fluid in the blind loop of bowel. Megaloblastic anemia is probably a result of successful competition by bacteria for vitamin B12. The Schilling test reveals a type of urinary excretion of vitamin B12 similar to that seen with pernicious anemia except that it is corrected, not by the addition of intrinsic factor, but by the use of oral tetracycline. Although the administration of tetracycline and parenteral vitamin B12 can correct megaloblastic anemia, only surgical correction of the cause of the bowel stasis is curative. Surgical correction includes converting the Billroth II to a Billroth I operation or the creation of Roux-en-Y limb gastrojejunostomy with a vagotomy to prevent marginal ulceration.

Answer 37

ANSWER: A COMMENTS: SBS may be diagnosed when there is significant malabsorption of vitamins and minerals or an inability to maintain caloric enteral nutrition in the setting of extensive small bowel resection. The usual quoted rule that less than 100 cm of intact small bowel results in SBS is not terribly useful since SBS may develop in a variety of situations and amounts of residual bowel. The normal length of small bowel from the ligament of Treitz to the ileocecal valve is about 500 cm, but a wide range was found, from 250 to 850 cm, in a recent study. The entire jejunum can be resected without adverse nutritional sequelae. The entire ileum can be resected without harm as long as vitamin B12 is administered regularly afterward. Up to 70% of the small bowel can be resected safely if the terminal ileum and ileocecal valve are left intact. If they are resected, however, loss of 50%–60% of the small bowel can lead to severely compromised nutrition. The deficiencies created by extensive resection of the small bowel are vitamin B12 malabsorption (terminal ileum), altered fat absorption, and fluid and electrolyte problems. Vitamin B12 malabsorption leads to vitamin B12 deficiency and megaloblastic anemia. Altered fat absorption produces steatorrhea as a result of several factors. First, massive small bowel resection leads to gastric hypersecretion because decreased bowel pH stimulates the intestine, thereby shortening transit time and interfering with the absorption of ingested fat. Second, interruption of bile salt resorption interferes with micelle formation. Third, the unabsorbed fats are irritating to the colonic mucosa, thereby increasing diarrhea and steatorrhea associated with the syndrome. Fluid and electrolyte problems are a function of the shortened transit time and diarrhea that results from loss of small bowel absorptive area. Treatment of SBS centers on control of diarrhea and parenteral maintenance of nutrition. With time (2 to 3 years), the mucosa of as little as 30 to 45 cm of small bowel may undergo enough hypertrophy to allow withdrawal of intravenous alimentation and the start of carefully modified oral feedings. Treatment with growth hormone, glutamine, and fiber has shown some promise in stimulating gut regeneration. Diarrhea can be controlled with agents such as Lomotil or codeine that slow intestinal motility. Oral calcium carbonate is also useful and acts by neutralizing hydrochloric acid and free fatty acids. When oral intake is resumed, dietary fat is restricted to 30 to 50 g daily. Some patients benefit from the use of medium-chain triglycerides. Oral bile salts are tolerated and aid in the formation of micelles in some patients, whereas in others, they cause increased diarrhea. Cholestyramine, an agent that sequesters bile acids, is useful in patients who have had less than 100 cm of small bowel resected. There is no standard approach to the resumption of oral intake, and treatment must be highly individualized. Although some patients ultimately do well with a modified oral diet, others remain dependent on permanent parenteral nutrition. There are no operative procedures that reliably correct SBS. Therefore operative treatment should be considered only in patients who cannot maintain their body weight within 30% of normal without intravenous supplementation. Operations that may be useful are reversal of a segment of intestine, creation of a recirculating loop of small bowel, creation of an artificial sphincter, vagotomy and pyloroplasty, correction of bowel obstruction, and placing all bowel in continuity (i.e., reversal of preexisting stomas). Vagotomy and pyloroplasty have rarely been performed for SBS since the introduction of H2 blockers and proton pump inhibitors. Allotransplantation of small bowel in humans has been performed successfully, but has a high failure rate and is only available in a few specialized centers.

Answer 38

ANSWER: B COMMENTS: The hematoma should be observed for several minutes to evaluate if it is expanding. If there is no evidence of expansion or ongoing bleeding, one can proceed with closing. Not every hematoma requires intervention. If the hematoma is large or expanding, the mesentery should be opened and explored. Hematomas can expand and tamponade the veins, leading to arterial inflow obstruction and poor blood flow to the anastomosis. Only if you cannot adequately control the hematoma should the involved segment be resected and the anastomosis redone.

Answer 39

ANSWER: E COMMENTS: Nodules of lymphoid tissues found throughout the small intestine and colon are known as Peyer’s patches. IgA is elaborated by plasma cells and is unique in that this immunoglobulin is transcytosed directly across enterocytes or hepatocytes for secretion directly into the intestinal contents or bile. Peyer’s patches are part of the mucosal-associated lymphoid tissue (MALT).

Answer 40

ANSWER: C COMMENTS: Primary enteral tuberculosis is rare in the United States, but is still common in underdeveloped countries where ingestion of unpasteurized milk occurs more commonly. Usually, it causes minimal symptoms, but occasionally, it results in stricturing and stenosis in the ileocecal area. The radiographic findings may be indistinguishable from those of carcinoma of the colon. Although it may be necessary to resect bowel because of high-grade obstruction, it is not appropriate to do so simply to establish the diagnosis. This can be accomplished with biopsy alone. Treatment with isoniazid, p-aminosalicylic acid, and streptomycin usually suffices. Ulcerative tuberculosis is a form that develops secondary to pulmonary disease and is more common than the primary form of this disease in the United States. Symptoms are nonspecific and variable, but most often consist of pain and diarrhea. Suspicion should be raised in Asian patients, particularly those coming from the Indian subcontinent. The most common laboratory findings are anemia and an elevated C-reactive protein. The diagnosis can be strongly suggested by barium examination, CT with intravenous (IV) and per os (po) contrast, or MR enterography. Confirmation is obtained by a positive tuberculin skin test, although a negative test does not rule out the diagnosis. Not infrequently, the diagnosis is made by open or laparoscopic exploration and biopsies. An appropriate response to antitubercular therapy also confirms the diagnosis. Surgery is best reserved for complications such as perforation, obstruction, or hemorrhage.

Answer 41

ANSWER: A COMMENTS: Typhoid enteritis, a systemic infection caused by S. typhi, is accompanied by fever, headache, coughing, maculopapular rash, abdominal pain, and leukopenia. Hyperplasia and ulceration of Peyer’s patches, mesenteric lymphadenopathy, and splenomegaly also occur. Chloramphenicol is not the drug of choice because of the emergence of resistant strains of bacteria and the risk for marrow toxicity. Currently, trimethoprim-sulfamethoxazole (Bactrim) is preferred. Patients who remain in a toxic state after 1 week of therapy often benefit from a short course of prednisone. Bleeding occurs in 10%–20% of patients and is usually treated by transfusion. Perforation through ulcerated Peyer’s patches occurs in 2% of patients and is most often free, solitary, and located in the terminal ileum. Operative closure and appropriate peritoneal toilet are required. Occasionally, the perforations are multiple, which necessitates intestinal resection with primary anastomosis.

Answer 42

``` Continuity maintained End fistula No associated abscess Healthy adjacent bowel Free flow distally Duodenal stump Jejunal Tract >2cm Defect <1cm Patients with optimal nutritional status ```

Answer 43

``` Compete disruption Lateral fistula Associated abscess Diseased adjacent bowel Distal obstruction Lateral duodenal Ileal Tract <2cm Defect >1cm Patients with poor nutritional status ```

Answer 44

``` Foreign body within tract Radiation enteritis Infection/inflammation Epithelialization of the tract Neoplasm at the fistula origin Distal obstruction of the intestine ```

Answer 45

>90% in 1 month <10% after 2 months None after 3 months

Answer 46

Either within 10 days of diagnosis or after 4 months

Answer 47

<5% of primary GI malignancies arise from small intestines 1/3 of primary small bowel neoplasms are benign 2/3 are malignant Less common in women (M>F) 6th-7th decade of life Malignant more common in distal small bowel (except adenoCA— duodenal predilection)

Answer 48

If <2cm: endoscopic polypectomy If >2cm: transduodenal polypectomy or segmental duodenal resection, or pancreaticoduodenectomy

Answer 49

- Endoscopic polypectomy | - Surveillance endoscopy at 6 month intervals, then annually

Answer 50

- Pancreaticoduodenectomy for proximal lesions (right of superior mesenteric artery) - Segmental resection for distal duodenal lesions (left of SMA)

Answer 51

Segmental resection with 5cm of tumor free proximal and distal margins

Answer 52

Wide en bloc resection (include adjacent mesenteric and LN)

Answer 53

Debulking surgery

Answer 54

- Preoperative somatostatin or octreotide - Debulking including resection of hepatic mets - Loperamide, diphenoxylate, or cyproheptadine (serotonin receptors antagonist) for the diarrhea - Type 1 and 2 histamine receptor antagonists for flushing - Albuterol and aminophylline for bronchospasm and wheezing.

Answer 55

Wide local excision of primary tumor with in continuity resection of adherent organs

Answer 56

Imatinib (Gleevec)

Answer 57

Palliative resection or bypass (diversion)

Answer 58

- Primary chemotherapy (CHOP regimen) | - Segmental resection for tumor complications

Answer 59

16. (A) The small intestine arises from the midgut segment. The midgut segment extends between the ampulla of Vater and the distal transverse colon. It enters the physiological umbilical hernia at sixth week and returns to the peritoneal cavity by the tenth week. The vitellointestinal tract (site from which Meckel’s diverticulum arises) is attached to the antimesenteric margin of the distal ileum. The urachus is attached to the bladder. The intestinal lymphatic drainage is directed to the preaortic glands.

Answer 60

17. (D) The small intestine commences to the left of the midline at Treitz’s ligament and ends at the ileocecal junction. The mesenteric attachment is only 15 cm in length. It is supplied by the midgut vessel (superior mesenteric). The sympathetic and parasympathetic (vagus) nerves enter the mesentery to supply the vessels and gut wall.

Answer 61

20. (D) Gangrene of the bowel occurs before the ominous sign of intramural air can be detected. The stack-of-coins sign is seen in intestinal obstruction where the proximal small intestine folds are stacked to provide this characteristic feature on a plain x-ray of the abdomen.

Answer 62

21. (C) In a patient with small intestine infarction, the possibility of nonocclusive ischemic disease should be excluded by angiography. If there is no evidence of gangrene, then fluid resuscitation and intra-arterial superior mesenteric papaverine administration may be adequate, and surgical intervention may be avoided. Von Willebrand’s disease is characterized by a mild to moderate fall in factor VIII levels (pseudohemophilia) but with a much milder bleeding tendency than in true hemophilia. It affects males and females equally.

Answer 63

22. (C) Most air that reaches the stomach and intestines comes from swallowed air. Air is nearly always seen in the small intestine on a plain film of the abdomen. Gas in the stomach is derived mainly from swallowed air, which has an oxygen content of 20% and nitrogen content of 80%. CO2 is formed by organic fermentation and comprises 40% of the gases in the distal bowel. Nitrogen is absorbed so that it is reduced below 50% distally. Methane and hydrogen sulfide gases are added in the distal bowel.

Answer 64

23. (D) A plain film of the abdomen shows valvulae conniventes in jejunal (proximal) obstruction, a featureless bowel pattern in distal ileal obstruction, and haustra in colon obstruction.

Answer 65

24. (A) The initial management of intestinal obstruction is to correct fluid and electrolyte imbalance. Surgery is indicated if strangulation is anticipated or if the obstruction fails to respond to conservative management. Nasogastric suction is often effective in obstruction because of adhesions but is contraindicated when the obstruction is caused by a hernia and/or strangulation is suspected.

Answer 66

25. (B) In patients presenting with small-bowel obstruction, clinical examination can usually identify a groin swelling attributable to strangulated hernia. If external groin hernia is excluded, the presence of an abdominal scar would highly suggest that intestinal obstruction is caused by adhesions. Peritoneal metastasis and primary tumors, bands, Crohn’s disease, and gallstone ileus must be excluded. The distention is mainly a result of swallowed air. If the obstruction is proximal, the onset is usually more severe and rapid.

Answer 67

26. (D) In a Richter hernia, only part of the circumference of the bowel wall has become trapped in the hernia sac, and normal bowel movements may still occur. In the presence of a reducible groin hernia, it is important on clinic examination to be certain that other pathologic conditions are not overlooked.

Answer 68

27. (E) Primary small-bowel volvulus is common in countries where the diet is high in bulk. Except for the neonatal variety (associated with malrotation), it is rare in the United States. Small-bowel volvulus secondary to adhesions is more common here. The ileum is more frequently involved than the jejunum. If a small-bowel resection is required, it is usually of a limited nature.

Answer 69

28. (C) The ileum is the exclusive site of bile salt absorption, and failure of its absorption contributes to the steatorrhea. Ileal resection, which at times includes the ileocecal valve, is more commonly performed than is proximal resection. Over a longer period of time (2–3 years), megaloblastic anemia occurs.

Answer 70

29. (A) Transit time in the ileum is slower than that in the jejunum. Resection of equal lengths of intestine results in greater deterioration after ileal resection as the site of slower (and therefore more complete) absorption is removed. Jejunal resection is followed by hypertrophy of the residual villi in the ileum and functional compensation to a degree greater than in the jejunum after ileal resection.

Answer 71

30. (B) Massive resection occurs if more than 75–80% is resected (leaving less than 1 m of small bowel). The most common indications for major bowel resection are ischemia, Crohn’s disease, volvulus, and trauma.

Answer 72

31. (A) In the blind loop syndrome, bacteria proliferate in an affected segment that fails to show appropriate peristaltic activity. It may be seen in surgery requiring jejunal or ileal bypass, small intestinal diverticular disease, scleroderma, diabetes mellitus, and intestinal carcinoma. Macrocytic anemia, caused by malabsorption of Vitamin B12 and folic acid, is a key diagnostic feature in its diagnosis.

Answer 73

32. (C) Intestinal obstruction due to a Meckel’s diverticulum may result from a volvulus, band obstruction, or intussusception. Among children, bleeding and inflammation are seen more frequently. Meckel’s diverticulum is a remnant of the vitellointestinal duct.

Answer 74

33. (B) Peutz–Jeghers syndrome is rare but should be considered if pigmented spots are found on the lips, mouth, or hands. Hamartomas are not neoplasms; the name is derived from the Greek hamartos, which refers to the misfiring of a javelin. The tissues appropriate to the site misfire and are arranged in an irregular order.

Answer 75

34. (A) Unfortunately, in most series, division of adhesions accounts for as much as 25% of postoperative intestinal fistulas. These cases usually involve sites that are not recognized at the time of operation. The fistulas occurring after resection of the bowel in Crohn’s disease are less likely to heal without surgical intervention. The small intestine is the most common site of intestinal fistula formation.

Answer 76

35. (B) Internal small-bowel fistulas are caused almost exclusively by small-bowel disease or surrounding visceral disease involving the small bowel. Crohn’s disease is the most common cause of internal small-bowel fistulas, but neoplasia, lymphoma, and tuberculosis must be excluded. Internal fistula may be asymptomatic or cause serious malabsorption (proximal to distal fistulas) or infection (enterovesical fistulas).

Answer 77

79. (B) The carcinoid syndrome in patients with intestinal carcinoid tumors will occur only in the presence of hepatic metastasis. Approximately 40% of patients with hepatic metastasis from an ileal carcinoid will develop the syndrome.

Answer 78

80. (A) Patients with carcinoid tumor due to ovarian dermoid or pulmonary lesion may develop the syndrome with an elevated 5-HIAA, although hepatic metastasis are absent. The liver does not counteract the hormone in this instance, because the portal system is bypassed.

Answer 79

81. (A) Patients with underlying ischemic disease may develop acute intestinal infarction or intestinal angina, which is aggravated by eating.

Answer 80

82. (A) Mechanical obstruction implies a barrier that impedes progress of intestinal contents. Complete mid- or distal small-bowel obstruction presents with colicky abdominal pain, more marked abdominal distention but with vomiting that is less frequent and occurs at a later stage than that of proximal jejunal obstruction.

Answer 81

83. (E) MMC are isoperistaltic waves and occur approximately once every 90 minutes. Oral feeding inhibits the MMC for as much as 3–4 hours. The inhibition of the MMC in the stomach and intestine may account in part for nausea and vomiting occurring after surgery. The major force that drives chyme aborally is that of segmentation and not the MMC.

Answer 82

84. (A) Typhoid fever typically presents with initial symptoms. Small intestine complications are related to involvement of Peyer’s patches of the small intestine, which result in bleeding and/or perforation in the second and third week after symptoms are noted.

Answer 83

85. (B) The absence of loops of colon makes a colonic site most unlikely as a cause of the current clinical presentation. Distention does not occur in high small-bowel obstruction.

Answer 84

86. (E) In view of the presence of bowel obstruction, surgery is indicated. In general, patients who have obstruction due to adhesions may undergo an initial short trial period of conservative management. Laparotomy is usually indicated in bowel obstruction due to other causes, where gangrene may be evident, and in all cases in which an initial period of conservative treatment fails.

Answer 85

88. (C) Tuberculosis is the great mimicker of disease and, therefore, should always be considered in the differential diagnosis of different abdominal conditions. Surgical intervention will be required if the obstruction becomes complete.

Answer 86

89. (A) Although intestinal tuberculosis still remains relatively uncommon in the United States, it should be particularly excluded in the AIDS population. In these patients, the rarity of the condition may make its clinical detection particularly difficult. Always suspect tuberculosis in the differential diagnosis of fever without a clearly defined cause.

Answer 87

90. (B) The blood supply to a loop of ischemic bowel is determined by the presence or absence of arterial pulsation, peristalsis, and color of the bowel after resuscitation and relief of obstruction.