Small Bowel Flashcards
A 55-year-old female with a long standing history of Crohn’s disease presents to the ER with severe diarrhea. She has a history of multiple bowel resections and is frequently admitted to the hospital for rehydration and electrolyte repletion. All of the following are true of her condition EXCEPT:
A. Increased likelihood of gallstones
B. increased likelihood of kidney stones
C. Mainstay of treatment is TPN and enteral feeding when tolerated
D. Diagnosis is made if patient has less than 150cm of small bowel or less than 70cm with a competent ileocecal valve
E. Jejunal resections are better tolerated than ileal resections
D. Diagnosis is made if patient has less than 150cm of small bowel or less than 70cm with a competent ileocecal valve
A 42-year-old male has an extensive history of partial small bowel obstructions that resolve with conservative management. He has not had any previous surgical interventions. After thorough workup, the patient has a Tx-pertechnetate scan that shows uptake proximal to the ileocecal valve. What is the BEST next step in management?
A. Observation and await resolution of obstruction
B. Diverticulectomy when obstruction resolves
C. Diverticulectomy if patient has GI bleeding
D. Segmental resection
E. Barium UGI with small bowel follow-through
B. Diverticulectomy when obstruction resolves
Where is the largest number of hormone-producing cells found in the body?
A. The pituitary
B. The small intestine
C. The pancreas
D. The liver
Answer: B
The small intestine is the body’s largest reservoir of hormone-producing cells.
Multiple specialized cells within the intestinal mucosa respond to luminal stimuli and secrete over 30 peptide hormones which regulate the functions of the intestine, other organs in the gastro-entero-pancreato-biliary system, the heart, and the brain.
(See Schwartz 10th ed., p. 1145.)
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
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 10th ed., p. 1138.)
Within the intestine, epithelial cells originate rom stem cells, proliferate in the crypts, and migrate up the villus in 2 to 5 days.
This process replaces cells that are removed due to apoptosis or exfoliation.
This rapid turnover makes the small intestine susceptible to
A. Radiation damage
B. Starvation
C. Exogenous steroids
D. Hypothermia
Answer: A
The high cellular turnover rate of enterocytes makes the small intestine susceptible to damage by inhibitors of proliferation such as radiation and cytotoxic chemotherapy.
(See Schwartz 10th ed., p. 1138.)
A pocket- or sock-like outpouching on the anti-mesenteric 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.
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 10th ed., p. 1139.)
How much fluid normally enters the adult small intestine each day?
A. 2L
B. 4L
C. 6L
D. 8L
Answer: D
Eight to nine liters of fluid enters the small intestine daily, of which over 80% is absorbed.
This includes 2L from oral intake, 1.5L of saliva, 2.5L of gastric juice, 1.5L of bilio-pancreatic secretions, and 1L of fluid secreted by the small intestine.
(See Schwartz 10th ed., p. 1140.)
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 sodium-glucose co-transporter 1 (SGLT1), glucose transporter 2 (GLUT2), and glucose transporter 5 (GLUT5).
C. By endocytosis of enterocytes on the villus.
D. By facilitated diffusion through tight junctions between enterocytes.
Answer: B
The three terminal products of carbohydrate digestion are transported through the enterocyte brush border membrane via facilitative transporter proteins such as the sodium-glucose cotransporter 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 or these conditions are designed to inhibit these transporters.
(See Schwartz 10th ed., p. 1141.)
A 45-year-old female with a history of Crohn’s disease presents to the ER with abdominal pain, vomiting and distension. A CT scan is performed and shows inflammatory changes and a stricture located at the proximal duodenum causing an obstruction. After one week of conservative management, the patient has no improvement in symptoms. What is the BEST surgical option for the patient?
A. No surgery unless complicated by perforation, fistula or abscess to avoid bowel shortening
B. Heineke-Mikulicz strictureplasty
C. Finney strictureplasty
D. Gastrojejunostomy
E. Whipple procedure
D. Gastrojejunostomy
A 55-year-old female with a history of Crohn’s disease presents to the ER with severe diarrhea. She has a history of multiple bowel resections and is frequently admitted to the hospital for rehydration and electrolyte repletion. All of the following are true of her condition EXCEPT:
A. Increased likelihood of gallstones
B. Increased likelihood of kidney stones
C. Mainstay of treatment is TPN and enteral feeding when tolerated
D. Diagnosis is made if patient has less than 150cm of small bowel or less than 70cm with a competent ileocecal valve
E. Jejunal resections are better tolerated than ileal resections
D. Diagnosis is made if patient has less than 150cm of small bowel or less than 70cm with a competent ileocecal valve
A 64-year-old male presents to the ER with a one week history of abdominal pain. An ultrasound shows evidence of cholecystitis. The patient improves with IV antibiotics and the decision if made to bring the patient back in one month for cholecystectomy, after the inflammation has resolved. Just prior to follow-up, the patient returns to the ER with abdominal pain and distension. He has not had a bowel movement in five days. What is the next BEST study?
A. Abdominal xray
B. CT scan abdomen and pelvis
C. Ultrasound
D. HIDA scan
E. ERCP
A. Abdominal xray
A 64-year-old male presents to the ER with a one week history of abdominal pain. An ultrasound shows evidence of cholecystitis. The patient improves with IV antibiotics and the decision is made to bring back the patient in one month for cholecystectomy, after the inflammation has resolved. Just prior to follow up, the patient returns to the ER with abdominal pain and distension. He has not had a bowel movement in five days. The findings on imaging suggest an obstruction with the appearance of a gallstone near the terminal ileum. What is the BEST management of this patient’s condition?
A. Open cholecystectomy
B. Laparotomy, proximal enterotomy, and stone removal
C. Laparotomy, terminal ileotomy, stone removal and cholecystostomy tube
D. Laparotomy, proximal enterotomy, stone removal and cholecystectomy
E. Laparotomy, terminal ileotomy, stone removal, and cholecystectomy
D. Laparotomy, proximal enterotomy, stone removal and cholecystectomy
A 50-year-old female comes to the office complaining of intermittent abdominal pain, diarrhea, and flushing of her face and neck. She also notes having recent asthmatic attacks which she never had before. A CT scan is performed that shows a non-obstructing mass in the ileum and several lesions in the liver suggestive of metastasis. What hormone is associated with this disease?
A. Histamine
B. Dopamine
C. Acetylcholine
D. Norepinephrine
E. Serotonin
E. Serotonin
A 65-year-old female is diagnosed with colon cancer in the cecum and undergoes an open right colectomy. What is the appropriate order for the return of bowel function after abdominal surgery?
A. Stomach, small bowel, colon
B. Small bowel, stomach, colon
C. Stomach, colon, small bowel
D. Small bowel, colon, stomach
E. Colon, small bowel, stomach
B. Small bowel, stomach, colon
*if carcinoid syndrome: small bowel
A newly diagnosed Crohn’s patient comes to the hospital complaining of abdominal pain. CT scan of the abdomen reveals a single 2cm area of stricture in the distal small bowel. You take the patient to the operating room and note a stricture without evidence of surrounding acute inflammation or phlegmon. The BEST treatment option is:
A. Limited resection
B. Balloon dilatation
C. Heineke-Mikulicz Stricureplasty
D. Medical management
E. Finney Strictureplasty
C. Heineke-Mikulicz Stricureplasty
A 61-year-old female sustains an iatrogenic enterotomy during abdominal laparotomy. Which layer of the intestinal wall is MOST important in maintaining tensile strength while constructing a hand-sewn anastomosis?
A. mucosa
B. submucosa
C. muscularis
D. serosa
B. submucosa
A 25-year-old females comes to your office complaining of crampy abdominal pain and diarrhea over the last few weeks. She has a colonoscopy performed that shows evidence of Crohn’s disease. All of the following favor a diagnosis of Crohn’s disease over ulcerative colitis EXCEPT?
A. Granulomas
B. Rectal involvement
C. Cobblestone appearance
D. Transmural involvement
E. Patchy areas of diseased bowel
B. Rectal involvement
A patient presents to your office with flushing, diarrhea, hepatomegaly, pulmonary stenosis, and asthma symptoms. He undergoes a CT scan of the chest, abdomen and pelvis to determine the location of the primary tumor. What is the most likely site for the primary tumor in this patient?
A. Small bowel
B. Appendix
C. Lung
D. Rectum
E. Ovary
A. Small bowel
A patient has a small bowel resection for lesion identified on CT scan. The pathology report indicates the lesion is consistent with metastatic diseases. Which of the following is the MOST likely location of the primary tumor?
A. Adrenal gland
B. Liver
C. Stomach
D. Skin
E. Thyroid
D. Skin
*Melanoma–> mets to small bowel
A 25-year-old male comes in with high-output enter-cutaneous fistula. Which of the following acid-base derangements is most likely present?
A. Metabolic acidosis
B. Metabolic alkalosis
C. Mixed respiratory and metabolic alkalosis
D. Mixed respiratory and metabolic acidosis
A. Metabolic acidosis
A 30 year- old frail lady presents to the emergency room for progressive weakness and weight loss. She just underwent right hemicolectomy for obstructing GITB 3 weeks ago. Which of the following is not a metabolic consequence of the patient’s previous surgery?
A. Megaloblastic anemia
B. Cholera-like diarrhea
C. Low levels of serum iron
D. Vitamin B12 deficiency
C. Low levels of serum iron
45/M consults for progressive abdominal dissension and constipation. Last bowel movement was 3 days ago with note of passage of gas a few hours back. Patient denies any previous abdominal surgery and any co-morbidity. Which diagnostic exam would be best to determine course of management?
A. Plain abdominal x-ray, supine and upright
B. Upper gastrointestinal series with small bowel follow-through
C. CT scan with contrast
D. MRI of abdomen
C. CT scan with contrast
A Meckel diverticulum is derived from which of the following structures?
A. Allantois
B. Connecting stalk
C. Vitelline duct
D. Urachus
C. Vitelline duct
A 32-year-old male presents with high grade fever of 2 weeks duration, lower abdominal pain and tenderness of 2 days duration. PE shows absent bowel sounds, abdominal rigidity and rebound tenderness. Their most likely differential diagnosis is?
A. Ileocecal tuberculosis
B. Meckel diverticulitis
C. Ruptured appendicitis
D. Typhoid ileitis with perforation
D. Typhoid ileitis with perforation
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: 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.
With regard to ileostomy physiology, which of the following statements is true?
A. Daily output from an established ileostomy is approximately 1500 mL.
B. Ileostomy output can increase by 50% at times of dietary indiscretion.
C. With dehydration, the concentration of sodium output from the ileostomy rises.
D. Compared with normal ileal fluid, ileostomy effluent contains a 100-fold increase in aerobes and a 2500-fold increase in coliform bacteria.
E. The microbiologic flora of ileostomy output is similar to that of normal ileal fluid.
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.
A patient undergoes a contrast radiograph of the small bowel for evaluation of intestinal pseudo-obstruction. The average transit time from the duodenum to the cecum is:
A. 30 min B. 1 h C. 3 h D. 5 h E. 7 h
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.
Which of the following statements about small bowel motility is true?
A. Oral feeding stimulates the production of migrating motorcomplexes (MMCs).
B. If motility is impaired, absorption of nutrients is similarly affected.
C. MMCs are peristaltic contractions occurring at 10- to 20-min intervals.
D. Vagotomy-induced diarrhea is the result of increased
secretion secondary to denervation.
E. Segmental bowel resection causes a temporary interruption of MMCs, but the clinical results are usually insignificant.
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.
A 27-year-old man with a long-standing history of Crohn’s disease is noted to have several extraintestinal manifestations of Crohn’s disease including erythema nodosum, arthritis, ankylosing spondylitis, anemia, and episodes of pancreatitis. During evaluation of his right lower quadrant pain, he is found to have a segment of thickened ileum causing obstruction. Which extraintestinal manifestations of his Crohn’s disease would you not expect to subside after resection of the involved segment of bowel?
A. Erythema nodosum
B. Arthritis
C. Ankylosing spondylitis
D. Anemia
E. Pancreatitis
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.
A patient with Crohn’s disease and obstructing chronic fibrotic small bowel strictures not responding to medical therapy is taken to the operating room. Appropriate surgical management includes:
A. Resecting the diseased segments with frozen section evaluation of the margins
B. Avoiding bowel resection for long strictures
C. Resecting bowel to palpably normal tissue
D. Resecting only the obviously obstructing segment and preserving as much bowel as possible
E. Performing no more than two stricturoplasties during a single operation
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.
Which of the following statements is true of the microscopic
appearance of Crohn’s disease?
A. The disease is confined to the mucosa and submucosa.
B. Identification of noncaseating granulomas is required for diagnosis.
C. Granulomas demonstrating caseation without acid-fast bacilli confirm the diagnosis.
D. Submucosal fibrosis occurs secondary to bacterial invasion.
E. Marked lymphangiectasia is a prominent microscopic feature.
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.
Diarrhea is one of the common clinical manifestations of Crohn’s disease. Which of the following statements is true regarding this manifestation?
A. Most patients experience intermittent bloody diarrhea.
B. Diarrhea is the result of segmental inflammation, leading to decreased small bowel absorption.
C. Decreased bile salt absorption in the diseased terminal ileum produces choleretic diarrhea.
D. Diarrhea is frequently described as mucus or pus like.
E. Bloody diarrhea almost always produces anemia.
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.
A 26-year-old woman with a history of Crohn’s disease is experiencing a flare of her disease. She is 6 weeks pregnant. Which of the following is true regarding the use of corticosteroids in patients with inflammatory bowel disease?
A. Corticosteroids are unsafe to use in pregnant patients with an acute flare of Crohn’s disease.
B. Corticosteroids effectively maintain remission of Crohn’s colitis and ulcerative colitis during pregnancy.
C. Corticosteroids used in enema (topical) form are not absorbed into the systemic circulation and therefore have no systemic side effects.
D. Therapy every other day is effective in pregnant patients during acute flares.
E. Intravenous corticosteroids and adrenocorticotropic hormone (ACTH) are equally effective in patients with acute severe ulcerative colitis that is refractory to oral treatment during pregnancy.
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.
During resection of the terminal ileum and ascending colon for Crohn’s disease, a 38-year-old man had 3 feet of small bowel removed. Six months later, he presents complaining of persistent diarrhea. Contrast studies and endoscopy are normal. The most likely etiology is:
A. Malabsorption of bile salts
B. Reactivation of Crohn’s disease
C. Gastric acid hypersecretion
D. Bacterial overgrowth
E. Partial bowel obstruction
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.
Nutritional support may be beneficial in patients with inflammatory bowel disease refractory to medical treatment. Which of the following statements is true?
A. Bowel rest and parenteral nutrition are the primary therapy for Crohn’s colitis.
B. In those with Crohn’s disease and a high-output fistula, total parenteral nutrition (TPN) promotes closure of the fistula.
C. TPN helps prevent the need for total colectomy in patients with ulcerative colitis.
D. In patients with Crohn’s ileitis, TPN is superior to enteral nutrition for providing an adequate caloric replacement.
E. An elemental diet is the primary therapy for exacerbation of Crohn’s disease.
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.
A 30-year-old woman has a bowel obstruction secondary to Crohn’s disease. She has undergone multiple previous small bowel resections. At laparotomy, multiple strictures are noted throughout her bowel. Which of the following statements is true?
A. Stricturoplasty should be considered only for patients with an isolated stricture.
B. Segmental bowel resections are preferable to stricturo- plasty for the current laparotomy.
C. Restricture at the stricturoplasty site has been seen in less than 5% of patients.
D. Anastomotic leakage and fistula formation following stricturoplasty have been seen in 50% of cases.
E. Because residual disease is left behind, reoperation for Crohn’s disease is more likely with stricturoplasty than with bowel resection.
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%.
A 54-year-old man is being assessed for colicky abdominal pain and occasional nonbilious emesis. He denies fevers and does not have leukocytosis. He has a history of melanoma that was resected from his arm 5 years earlier. His upper GI (UGI) radiograph is shown in Fig. 22A.1. What is the next best step in this patient’s management?
A. Barium enema with pneumatic decompression
B. Exploratory laparotomy and manual reduction
C. Exploratory laparotomy, manual reduction, and resection of the involved segment
D. Nasogastric tube placement, intravenous fluid, and a trial of nonoperative management
E. Exploratory laparotomy and intestinal bypass
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.
A 26-year-old man arrives at the emergency department with a complaint of recurrent, colicky, mid-abdominal pain. Physical examination reveals a palpable abdominal mass and several areas of increased pigmentation on his lips, palms, and soles. He states that his father had a colon polyp removed several years ago. Computed tomography (CT) of the abdomen was performed (Fig. 22A.3). PJS is suspected. Which of the following is true of PJS?
A. It is a sex-linked recessive familial disease characterized by intestinal polyposis and mucocutaneous hyperpigmentation.
B. Polyps are most frequently located in the jejunum and ileum but can also be found in the stomach, duodenum, colon, and rectum.
C. Surgical treatment includes resecting all bowel containing polyps.
D. Peutz-Jeghers polyps have a high malignant potential.
E. Peutz-Jeghers polyps are typically adenomatous.
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.
Which of the following statements is true concerning the causes of intestinal obstruction?
A. Among adults, 20% of intussusception cases are associated with a pathologic process, most commonly a tumor.
B. A leading cause of bowel obstruction is early postoperative adhesions.
C. In the United States, adhesions account for more than 50% of cases of small bowel obstruction.
D. Richter’s hernia cannot lead to complete obstruction.
E. Hernias are the leading cause of obstruction in the United States.
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.
Which of the following is true concerning postoperative ileus (POI)?
A. The presence of peritonitis at the time of surgery delays return of normal function.
B. The use of metoclopramide hastens the return of motility.
C. Contrast radiographic studies have no role in differentiating early postoperative bowel obstruction from POI.
D. The judicious use of intravenous patient-controlled analgesia has no effect on the return of small bowel motor activity.
E. Alvimopan has not been shown to affect the return of small bowel motor activity.
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.
Which of the following is true regarding the initial treatment of patients with acute, complete small bowel obstruction?
A. Immediate surgery is warranted as soon as the diagnosis is made.
B. Nasogastric decompression should be used for as long as possible in patients with complete small bowel obstruction to allow resolution.
C. The presence of fever, tachycardia, localized pain, or leukocytosis suggests strangulation and warrants prompt surgery.
D. All patients with complete small bowel obstruction require blood and plasma for resuscitation.
E. If a small bowel resection must be performed, a stoma and mucous fistula are necessary because of the high risk of anastomotic failure.
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.
An 85-year-old woman has severe abdominal pain and distention. She is tachycardic, oliguric, and acidotic. Abdominal radiographs show pneumobilia and a mass
(Fig. 22A.4). What is the best surgical management for this patient during an exploratory laparotomy?
A. Resection of the mass
B. “Milking” the mass distally past the obstruction
C. Cholecystectomy, enterotomy, and removal of the mass
D. Enterotomy and removal of the mass
E. Hepaticojejunostomy
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.
A 4-year-old male presents with blood per rectum. Technetium-99 pertechnetate scintigraphy suggests a bleeding Meckel’s diverticulum. Which of the following is the appropriate treatment?
A. Ileal segmental resection with primary reanastomosis
B. Diverticulectomy
C. Medical management with proton pump inhibitor and octreotide
D. Angiography for embolization
E. Push enteroscopy for endoscopic treatment
ANSWER: A
COMMENTS: See Question 20.
A woman is undergoing an open incisional hernia repair through a previous cesarean section incision. During the operation, this structure (Fig. 22A.5) is noted about 60 cm from the ileocecal valve. What is true regarding this incidental finding?
A. It is a true diverticulum.
B. This lesion may be found in various anatomic forms in 50% of the population.
C. Pancreatic tissue is the most common ectopic tissue found in this diverticula.
D. Most complications occur in the elderly.
E. Diverticulitis is the most common complication
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.
