Colon

Question 1

A 58-year-old woman presents to the emergency department (ED) with abdominal pain and distension. She has a history of spina bifida with a neurogenic bladder and chronic constipation, for which she takes an osmotic laxative on a daily basis. She has noted increasing abdominal pain for the week prior to presentation, and she has not passed any stool or gas for 4 days. She reports that she has had progressive abdominal distension and discomfort today, and now has nausea and vomiting, prompting evaluation. On exam, she is morbidly obese, has decreased bowel sounds, and tenderness throughout her abdomen, without guarding or rebound. Rectal examination reveals no palpable stool in the rectal vault. A computed tomography (CT) scan is done in the ED, with the results shown in the figure. Which of the following is the most likely diagnosis?

A. Ileus

B. Colonic malignancy

C. Bowel perforation

D. Diverticulitis

E. Sigmoid volvulus

Answer 1

This woman’s CT scan reveals a sigmoid volvulus, as evident by twisting displacement of the base of the sigmoid colon and mesentery, leading to significant upstream dilation of her colon, with her right colon measuring >15 cm in maximal dimension. Sigmoid volvulus is uncommon, and only accounts for 3-5% of intestinal obstructions, and patients tend to be older with chronic constipation who are institutionalized or have cognitive issues. Management includes urgent endoscopic detorsion, which can help to untwist the colon, and allows removal of air from the proximal distended colon with placement of a decompression tube, with a success rate of 60-80%. Surgery is often performed for patients after the colon has been decompressed in order to prevent recurrence, which is seen in up to 90% of patients. Although a colonic malignancy could cause a mechanical large bowel obstruction, the twisted appearance on the mid pelvis is more suggestive of a volvulus. There is no evidence of free air on the CT scan, so perforation is unlikely. The clinical and radiographic features are not typical for diverticulitis or ileus.

Question 2

A 66-year-old woman is admitted to the hospital with a 1-day history of abdominal pain and hematochezia. Her prior medical history is notable for poorly controlled type II diabetes mellitus, hypertension, hyperlipidemia, osteoarthritis, glaucoma, and alcoholic cirrhosis. She drinks a half pint of alcohol per day and has done so for 30 years. She smokes 1 pack of cigarettes per day and uses cocaine 3-4 times per month. Her last cocaine use was 3 days prior to admission. She takes ibuprofen 400-800 mg 2-3 times a day as needed for pain. Admission laboratory tests results reveal WBC 9,500/µL, hemoglobin 10 g/dL, INR 2.1, hemoglobin A1c 13.4, FOBT positive, C. difficile negative. She is observed in hospital and prepared for colonoscopy, which reveals the lesion shown in FIGURE A. Biopsy of this lesion is shown in FIGURE B. Which of the following therapies is most appropriate for this condition?

A. Mesalamine suppositories

B. Psyllium

C. Acyclovir

D. Metronidazole

Answer 2

• Histo: characteristic findings of solitary rectal ulcer syndrome (SRUS)
• Dx: clincial, histo, enod.
• Sigmoidoscopy usually demonstrates a single 1-cm ulcer on the anterior rectal wall within 10 cm of the anal verge. The ulcer may have a polypoid appearance in 25% of patients. In a minority of patients, only erythema and hyperemia of the mucosa are seen. Multiple ulcers may be seen in 30% of patients. Histologic features of SRUS include mucosal thickening with elongation, distortion of the glands, edema of the lamina propria, fibrosis, and extension of smooth muscle fibers upwards between the crypts. The hypertrophy and disorganization of the muscularis mucosa are referred to as fibromuscular obliteration
• Treatment includes local agents, improving bowel habits, biofeedback, and surgery. Patients should be placed on a high-fiber diet along with laxatives. They should also be educated to avoid excessive straining and digital manipulation and to reduce the time spent on the toilet.
• Surgery is indicated in patients with severe disease who do not respond to medical or biofeedback therapy or in those with full-thickness rectal prolapse.

Question 3

A 36-year old woman without significant past medical history presents for consideration of possible subtotal colectomy to address her refractory chronic constipation. She has had constipation for at least 12 years, during which time she has undergone trials of multiple different medications in succession including polyethylene glycol, bisacodyl, lubiprostone, and most recently linaclotide at therapeutic doses for several months each. She also has attempted tap water enemas as needed without relief. She is not on any other medications and denies any other neurologic symptoms.

At baseline, her stool consistency is hard (Bristol 1-2) and even on these laxative regimens, her stools remain solid (Bristol 2-3) and infrequent (every 8-12 days). She also reports bloating and straining with a sense of incomplete evacuation, but denies any issues with abdominal pain. Her prior evaluation includes a colonoscopy which noted retained stool throughout (Boston Bowel Prep Score=3) despite completion of a standard bowel prep, but an otherwise normal appearing colon; radiopaque marker study showed retention of all 24 markers, with 12 markers in the right colon and 12 markers in the left colon at day 6. A wireless motility capsule study revealed a whole gut transit time of 84 hours on her laxative regimen, and defecography demonstrated a small anterior rectocele without a dilated anorectum. Anorectal manometry was performed (bear down maneuver shown in the figure) and balloon expulsion testing yielded a failure to pass the balloon after 5 minutes. What therapeutic recommendation would you make for this patient?

A. Proceed with subtotal colectomy.

B. Repair anterior rectocele.

C. Trial of a tricyclic antidepressant.

D. Increase laxative regimen to include a combination of oral laxatives and suppositories.

E. Pursue biofeedback therapy and pelvic floor therapy program.

Answer 3

• This patient clearly has evidence of slow transit constipation with prolonged retention of radio-opaque markers and confirmed by delayed whole gut transit. She has no features of secondary constipation, and there is no evidence of bowel dilation to suggest mechanical obstruction or colonic pseudo-obstruction. She has failed multiple laxative regimens, decreasing the likelihood of a response to a complex laxative/suppository regimen. On this basis, subtotal colectomy seems a reasonable consideration; however, before proceeding, it is noted that the patient reports symptoms of dyssynergic defecation (straining, incomplete evacuation) and additionally, her anorectal manometry study and balloon expulsion testing suggest an overlapping pelvic floor dyssynergia, with failure to expel the balloon and paradoxical contraction during bear down maneuver. In light of these data, a biofeedback and pelvic floor therapy program should be initiated prior to pursuing a subtotal colectomy for slow transit constipation.
• The patient does not have pain as a predominant symptom, making irritable bowel syndrome with constipation unlikely, and accordingly the use of a tricyclic antidepressant a less attractive option. A small anterior rectocele is more likely a consequence (rather than a cause) of the patient’s defecatory issues.

Question 4

A 70-year-old woman with ulcerative colitis was scheduled for a surveillance colonoscopy. The endoscopist used chromoendoscopy and found a 16-mm sessile serrated polyp in the transverse colon. The endoscopist removed the lesion by hybrid endoscopic submucosal dissection en bloc as seen in the figure. Endoscopically resectable visible nonpolypoid dysplastic lesion removed using hybrid endoscopic submucosal dissection. A, Nonpolypoid superficial elevated serrated appearing lesion. B, The periphery of the lesion is marked, and the lesion is injected using dynamic submucosal injection. C, Circumferential incision. D, Some submucosal dissection. E, The lesion is ultimately resected en bloc using a stiff snare. F, The specimen is pinned for orientation and histologic assessment. Pathology reports indicated that the polyp is a sessile serrated adenoma without cytologic dysplasia. Which of the following is the recommended next step?

A. Schedule a 6-month follow-up colonoscopy.

B. Refer to a surgeon for hemicolectomy due to a high risk of CRC.

C. Schedule a surveillance colonoscopy in 3 years due to a low risk of CRC.

D. Schedule a surveillance colonoscopy in 1 month due to incomplete resection.

Answer 4

SCENIC guidelines recommend surveillance colonoscopy rather than colectomy after complete removal of nonpolypoid dysplastic lesions. Therefore, patients with IBD and large sessile serrated lesions without cytologic high-grade dysplasia removed via EMR, ESD, or in piecemeal fashion should be assigned a 3-6 month interval.

Question 5

A 75-year-old man with a history of adenomatous polyps presented for a follow-up colonoscopy, 3 years after resection of 2 high-grade dysplastic adenomas. In the ascending colon, a 2-cm flat lateral-spreading tumor (LST), granular-type lesion was found [FIGURE A]. It was completely removed by en bloc endoscopic mucosal resection (EMR). There was prophylactic clipping of the EMR defect [FIGURE B]. No cancer was found in the resection specimen. Which of the following is true for this patient?

A. Prophylactic coagulation of the exposed superficial vessel in the EMR defect will decrease the incidence of delayed bleeding after EMR.

B. The patient should have annual stool-based surveillance by fecal immunochemical test (FIT).

C. The patient should have surveillance colonoscopy in 3 years.

D. The patient should have a right hemicolectomy.

Answer 5

• LSTs are superficial. More than 10 mm in diameter, lesions extend more laterally than vertically in the colonic wall. There are 2 sub-types: a) granular type and b) nongranular type. Granular type LSTs with big nodules or depressed areas have higher risk of submucosal invasion. Therefore, removal needs expertise and completeness.
• This patient who had a 2-cm LST without malignancy and had complete en-bloc endoscopic resection should undergo surveillance colonoscopy in 3 years.
• Recently, a study showed that prophylactic coagulation of the EMR defect did not impact delayed bleeding rates. No FIT is indicated. Surgery is an alternative in incomplete resection (appendix base invasion, nonlifting sign) or in lesions with submucosal invasive carcinoma

Question 6

A 68-year-old woman with a history of hypertension, diabetes, and chronic obstructive pulmonary disease presents with 24 hours of cramping abdominal pain and bloody diarrhea. She notes that the symptoms started with the sudden onset of abdominal pain and was followed by 4 episodes of bloody diarrhea. In the emergency department, she is found to have a heart rate of 96 beats per minute and a blood pressure of 95/60. She receives 1 liter of normal saline and her vital signs improve to a heart rate of 75 beats per minute and blood pressure of 120/85. The patient has had no recent changes to her medications, sick contacts, or recent travel. Her last colonoscopy was 4 years ago and was remarkable for the presence of 2 tubular adenomas. She has a CT scan showing a segmental colitis. One week later, she has a colonoscopy with the finding shown in the figure. What is the most common segmental distribution for this patient’s disease?

single stripe sign seen

A. Cecum

B. Ascending colon

C. Transverse colon

D. Descending colon

E. Rectosigmoid colon

Answer 6

The patient has “colon ischemia” or “ischemic colitis.” This is clear from the description of the presentation, which is classic for this disease state. The patient also has the most significant risk factor for colon ischemia, which is COPD. Finally, the image shows the “single stripe sign,” the colonoscopic finding most commonly associated with colon ischemia. The most common distribution of colon ischemia involves the left colon, specifically the rectosigmoid colon. The disease distribution is also importantly associated with severity of disease. Patients with isolated right colonic disease distribution are at the highest risk for poor outcome.

Question 7

A 62-year-old man on clopidogrel with a history of hypertension, chronic obstructive pulmonary disease, and coronary artery disease with stent placement 2 years ago presents to the emergency department with acute onset of abdominal pain. He rates his abdominal pain to be 9/10 on a pain scale and describes it as a sharp band throughout his abdomen. He undergoes an initial x-ray [FIGURE]. What is the best next step in the management of this patient?

A. Ultrasonography with dopplers of the abdomen

B. Emergency laparotomy

C. Admittance to general medicine and intravenous fluids

D. CT angiography of the abdomen and pelvis

Answer 7

• The x-ray shows pneumatosis linearis lining the right colon. In this circumstance, there is concern for isolated right colon ischemia with possible necrosis.
• The most important next test is an angiographic study to delineate how to best treat the patient.
• Ultrasound with dopplers, and even CT of the abdomen and pelvis alone, might miss a vascular obstruction that requires immediate interventional radiology or vascular surgical intervention.
• Calling surgery for an emergency laparotomy might be best if there was clear evidence of a perforated viscus, but in this case, the vascular imaging is most important because that will triage the best methods to reverse the process.
• Admitting to medicine and treating with conservative measures would be a dangerous choice for this patient.

Question 8

A 55-year-old woman, para 2, without any history of back trauma or injury presents with a 4-year history of progressively worsening fecal incontinence. She cannot sense stool coming out and wets her pants frequently, using 3 pads daily. She had a normal colonoscopy 1 year ago. She denies any bleeding. Her stools are mostly formed (Type 4 on a Bristol stool scale). The patient trialed on psyllium without any relief of her incontinence. To assess this patient further, an anal ultrasound study was performed [FIGURE]. Which of the following findings best describes the anal ultrasound image?

A. Decreased resting and squeeze anal sphincter tone

B. Large external anal sphincter defect but normal internal anal sphincter

C. Normal external anal sphincter but large internal anal sphincter defect

D. Decreased squeeze tone

E. Large external and internal anal sphincter defect

Answer 8

• The anal sphincter profile was obtained during rest with an anal ultrasound probe.
• Typically, one would observe an intact homogenous hypoechoic internal anal sphincter (IAS) ring and an intact hyperechoic external anal sphincter (EAS) ring. In a patient with anal sphincter trauma (often obstetrical), there is loss of continuity in one or more sphincters and sometimes presence of a dense scar, usually in the anterior sector.
• Responses B and C are incorrect, because the anal sphincter defect involves both the EAS and IAS. Responses A and D are incorrect because an anal ultrasound test does not provide manometric information but morphological information

Question 9

A 56-year-old woman presents for screening colonoscopy. She has had 2 previous attempts at colonoscopy that were unable to be completed due to tortuosity of the colon. Those procedures were terminated in the transverse colon. Today, with the help of pressure, the scope is passed with ease to the cecum. She has three 1-2-mm sessile polyps resected with a cold biopsy forceps. Following the procedure, the patient feels well and is discharged. She calls you about 2 hours later stating that she is having excruciating abdominal pains. You return her call and advise her to go to the emergency department. In the ED, the abdominal x-ray reveals the following [FIGURE]. What segment of the colon is most likely involved with this complication?

A. Cecum

B. Ascending colon

C. Transverse colon

D. Descending colon

E. Sigmoid colon

Answer 9

The sigmoid colon has been shown to be the most common location for colonic perforation in multiple studies. The largest study that looked at this was a 16-year study with 30,366 colonoscopies. There were 35 perforations (0.12%) or 1 in 1,000. The most common location for perforation was the sigmoid colon with 26 perforations (74%).

Question 10

A 59-year-old woman presents with iron-deficiency anemia. You perform colonoscopy. On examination, a 25-mm malignant appearing mass was detected in the transverse colon. You request your pathologist perform immunohistochemistry (IHC) for expression of mismatch repair proteins on the biopsy specimens you obtain from the tumor. The IHC result is shown in FIGURES A and B. IHC of MSH2 is on the left [FIGURE A] and of MLH1 on the right [FIGURE B]. What is the best next step in the management of this patient?

A. Send patient for genetic counseling and testing for Lynch syndrome.

B. Perform microsatellite instability (MSI) testing on the tumor.

C. Test the tumor for a BRAF mutation.

D. Recommend prophylactic TAH/BSO at time of colon cancer surgery.

Answer 10

All colorectal cancers should undergo tumor testing for assessment of mismatch repair (MMR) deficiency (also known as microsatellite instability) by either MSI or IHC testing. In the figure, IHC of the tubulovillous adenoma from which the cancer arises demonstrates intact expression of the MSH2 protein and lack of expression of the MLH1 protein. Lack of expression is an abnormal result and confirms MSI and the specific MMR protein defect. The latter may be due to promoter methylation of MLH1 in the tumor which occurs in cancers arising from a sessile serrated polyp (SSP) or a germline mutation in the MLH1 gene which occurs in Lynch syndrome. The next step in determining the etiology of the cancer and optimal patient management is tumor BRAF mutation or MLH1 promoter methylation testing. If either are present, Lynch syndrome is excluded and suggests a sporadic cancer arising from an SSP.

Question 11

A 56-year-old man with no significant past medical history presented for screening colonoscopy. His examination was remarkable for a 1.8-cm laterally growing superficial area of irregular mucosa in the ascending colon that you suspect is a lateral spreading tumor (LST). What LST sub-classification [FIGURE] has the highest risk of submucosal invasive cancer?

A. Granular, homogenous

B. Granular, nonhomogenous

C. Nongranular, flat elevated

D. Nongranular, pseudodepressed

Answer 11

In one study of lateral spreading tumors (LSTs), submucosal invasion (SMI) was identified in 8.5% of cases and high-grade dysplasia in 36.7% of cases. Within this study, geographic region did not influence the SMI risk and nongranular LSTs were more frequently associated with SMI than granular LSTs: 11.7% vs. 5.9%. The prevalence of SMI in LSTs stratified by endoscopic LST subtype were: 31.6% in pseudodepressed nongranular LSTs, 10.5% in nodular mixed granular LSTs, 4.9% in flat elevated nongranular LSTs, and 0.5% in homogenous granular LSTs. Within that study, SMI was also more common in distal rather than proximal LSTs and the proportion of SMI increased with lesion size (10-19 mm, 4.6%; 20-29 mm, 9.2 %; ≥30 mm, 16.5%).

Question 12

A 65-year-old woman comes in for her first screening colonoscopy. She is asymptomatic and has no family history of colorectal cancer (CRC). The endoscopist found 4 polyps in the recto-sigmoid ranging from 2-4 mm as shown in the figure [hyperplastic polyps, NBI]. What would be the recommended next step?

A. Leave polyps in place

B. Cold large capacity forceps polypectomy

C. Cold snare polypectomy

D. Hot biopsy forceps

Answer 12

Using the NICE classification with narrow band imaging, these polyps can be diagnosed as hyperplastic with high confidence. It is recommended to leave hyperplastic diminutive polyps of the rectal and sigmoid colon in place. Using this classification, experienced endoscopists have achieved 93% concordance of surveillance intervals made by real-time optical diagnosis and pathology, and a >90% negative predictive value for rectosigmoid polyps when assessments were made with high confidence.

Question 13

Which of the following colorectal cancer screening test(s) has been proven (with randomized controlled trials) to reduce colorectal cancer mortality?

A. Fecal occult blood testing

B. Sigmoidoscopy

C. Colonoscopy

D. Fecal occult blood testing and colonoscopy

E. Fecal occult blood testing and sigmoidoscopy

Answer 13

• There have been several randomized controlled trials (RCTs) demonstrating that guaiac-based fecal occult blood tests (gFOBT) reduce colorectal cancer mortality by 33% with annual screening and 15-18% with biennial screening.
• Fecal immunochemical testing (FIT) identify intact human hemoglobin in stool and are more sensitive than gFOBT, but have not been proven in RCTs to reduce cancer mortality.
• There have been 4 RCTs of sigmoidoscopy use and colorectal cancer mortality, and these have demonstrated reduced cancer mortality compared to usual care (approximately 27% mortality reduction, by meta-analysis).
• While there are several RCT’s underway that compare colonoscopy to either usual care or to FIT, there is only indirect evidence of the mortality benefit of colonoscopy. This indirect evidence includes prospective cohort studies and case-control studies.

Question 14

A 60-year-old patient presented for a surveillance colonoscopy. He had a 35-mm flat granular type lesion removed by piecemeal resection. Coagulation forceps were used at the time of the EMR for bleeding hemostasis. Clips were placed to close the defect. The pathology showed tubular adenoma. Surveillance colonoscopy findings in 6 months show neoplastic recurrence at the site. What is the polyp feature most associated with higher risk of local recurrence?

A. Lesion size of 35 mm

B. Use of clips

C. Intraprocedure bleeding

D. Low-grade dysplasia

Answer 14

• Local neoplastic recurrence following endoscopic resection of large colorectal lesions has been reported in several longitudinal outcomes studies to be approximately 16%. It is typically unifocal and diminutive, and can be managed endoscopically.
• Risk factors associated with higher local recurrence rates include
  
  • lesion >40 mm
  • use of argon plasma coagulation to treat endoscopically visible residual lesion
  • intraprocedure bleeding
  • high-grade dysplasia
• A recursive partitioning analysis of patients who had endoscopic resection of advanced lesions and surveillance within 3 years showed the highest recurrence rate in those with a high-grade dysplastic lesion ≥15 mm.
• A recent recurrence prediction tool for lesions ≥20 mm was proposed to risk stratify patient surveillance intervals. Using a 4-point scale (size ≥40 mm = 2, intraprocedure bleeding = 1, high-grade dysplasia = 1), the cumulative incidence of recurrence in lesions with a score of 0 did not increase between 6 and 18 months (11.6%), where as the cumulative incidence of recurrence in lesions with a score of 1-4 increased from 23.0% at 6 months, 36.3% at 18 months, and 39.5% at 36 months.
• As such, low-risk lesions could potentially have first surveillance at 18 months, whereas high-risk lesions require intense early surveillance at 6, 18, and 36 months.

Question 15

A 35-year-old female ICU nurse presents in outpatient consultation for chronic diarrhea and abdominal pain. She reports 3-5 watery, nonbloody stools a day with associated abdominal cramping pain over the past several months, and she has presented to the emergency room on several occasions for pain control and concern that she may have acquired C. difficile at work. Her previous evaluation has included a normal complete blood count and metabolic panel, and negative stool testing for C. difficile toxin B by PCR on 2 separate occasions. Stool microbiologic testing for enteric pathogens and parasites is negative. Upper endoscopy, colonoscopy, biopsies of small bowel and colon, abdominal CT, and MR enterography are all normal. Stool electrolyte testing is ordered following the consultation, with the following results: Stool sodium 30 eEq/L, potassium 70 mEq/L, and stool osmolarity was 100 mEq/L. What is the most likely explanation for this patient’s test results?

A. Gastrinoma

B. Stool specimen contamination or dilution

C. Idiopathic secretory diarrhea

D. Small intestinal bacterial overgrowth (SIBO)

Answer 15

• The osmolarity of stool under normal circumstances is similar to plasma osmolarity (290 eEq/L). In this particular case, the low osmolarity suggests that the stool has been diluted, perhaps with hypotonic urine or water.
• This dilution may be accidental or volitional (factitious diarrhea). Stool urea can be measured to confirm contamination with urine.
• Factitious diarrhea is more common in women, especially those in health care professions.
• The calculated osmotic gap is 290 – 2x (30 +70) is 290-200 = 90, which is not the low gap (less than 50 mEq/L) that you would see with a secretory diarrhea, such as a gastrin producing tumor or idiopathic secretory diarrhea.
• SIBO more typically leads to a stool gap in osmotic range (>125 mEq/L) and would not be associated with a low stool osmolarity.

Question 16

A 70 kg patient is admitted to the hospital with presumed immune checkpoint inhibitor-induced colitis. The patient is having profuse watery diarrhea. Once fluid resuscitation is accomplished and other causes of diarrhea (C. difficile, CMV, etc.) have been ruled out, initial therapy should include which of the following?

A. Oral budesonide

B. Oral prednisone

C. IV methylprednisolone

D. IV Infliximab

Answer 16

Budesonide and oral prednisone are not consistently effective in patients ill enough to require hospitalization. While there are no large trials demonstrating the utility of IV steroids (typically 1-2 mg/kg dosing) for steroid refractory diarrhea, clinical experience to date supports a stepwise approach of oral steroid, IV steroid, and then anti-TNF therapy with uniformly good outcomes. For this inpatient, starting with intravenous steroid therapy would be most appropriate.

Question 17

A 53-year-old woman with no co-morbidities undergoes screening colonoscopy. The Boston Bowel Preparation Score is 9 and the cecum is intubated and documented with a photograph of the appendiceal orifice. In the left colon, a 25-mm pedunculated polyp is removed and the area tattooed. The pathology demonstrates cancer within the head of the polyp. Which of the following pathologic findings would prompt you to refer this patient for surgical resection?

A. There is tumor at the resected margin.

B. No lymphatic or vascular invasion is observed.

C. The tumor is well differentiated.

D. The tumor involves 35% of the head of the polyp

Answer 17

When cancer is found within a resected polyp, several features (primarily histologic) may be used to predict the risk for locally advanced disease involving lymph nodes. Unfavorable features which would prompt surgical resection include tumor at the resected margin or extending into the stalk, lymphatic or vascular invasion, poor differentiation, and extension into the submucosa. When carcinoma is confined to the head in a pedunculated polyp, and no unfavorable features are present, the risk for metastatic disease is very small and treatment with polypectomy alone is adequate

Question 18

What is the minimum performance target for overall ADR?

Answer 18

25%

Because some endoscopists perform colonoscopy for primarily male or female patients (e.g., endoscopists in Veterans Affairs hospitals or female endoscopists with largely female patient populations), an ADR target of 30% is recommended for men and 20% for women.

Question 19

A 58-year-old woman is found to have adenocarcinoma of the ascending colon during routine screening colonoscopy. She is asymptomatic and otherwise in good health. There is no family history of colorectal cancer or polyps. She undergoes right hemicolectomy, and immunohistochemistry of the surgical specimen shows lack of expression of MLH1 protein. Subsequent testing reveals a BRAF mutation. Which of the following is appropriate?

A. No further testing

B. Referral for genetic counseling

C. Surgical referral for completion colectomy

D. Tumor testing for microsatellite instability

Answer 19

Universal testing of CRC for Lynch syndrome (LS) is strongly advocated by several professional organizations. Immunohistochemistry of CRCs utilizing antibodies to the Mutation Mismatch Repair (MMR) gene proteins MLH1, MSH2, MSH6, and PMS2 evaluates for the loss of MMR protein expression. This loss can be due to germline mutation (as in Lynch syndrome), or somatic due to epigenetic silencing of the MLH1 gene by methylation. To distinguish these 2 mechanisms, testing can be done for mutations in the BRAF oncogene. Mutations in BRAF are usually seen in sporadic (non-LS) CRC, and associated with the CpG island methylator phenotype (CIMP) and microsatellite instability (MSI). Given that the patient described has no concerning family history and the molecular features of the CRC are that of sporadic cancer, then referral for genetic counseling and additional surgery are not indicated. Testing for MSI when IHC has already been performed is not necessary, but is a reasonable alternative option to IHC if this was not done or is not available

Question 20

An 18-year-old woman presents with 2 weeks of post-prandial epigastric pain and a 6-lb weight loss. The patient has no past medical problems or surgeries, and takes no medication. She is a senior in high school, does not use drugs or alcohol, and denies a history of abuse or an eating disorder. She is a thin, fit-appearing woman who is comfortable. She is 5’2”, 95 lb, BMI 17.4, P 72, RR 12, BP 96/67.

The following laboratory test results are within normal limits - CBC, TSH, metabolic panel, celiac panel, and lipase. An EGD is normal, and a gastric emptying scan with a semisolid meal has a gastric emptying time of 73 minutes (normal: 50-70 minutes). A CT scan of the abdomen with oral and IV contrast is performed and demonstrates narrowing of the aorta mesenteric angle measuring approximately 20 degrees. Further, these CT findings result in compression of the third portion of the duodenum between the SMA and aorta. The patient also undergoes an UGI series which demonstrates delayed passage of contrast past the duodenal bulb. The history and imaging support a diagnosis of SMA syndrome and you plan on treating the patient for this disorder. What do you recommend at this time?

A. Start low-dose metoclopramide after discussing the risks and benefits.

B. Start low-dose amitriptyline at bedtime after discussing the risks and benefits.

C. Refer the patient for surgery.

D. Start total parenteral nutrition.

E. Start nasojejunal tube feeds.

Answer 20

• While SMA syndrome is a controversial diagnosis, it is reasonable to consider in this patient. Consistent with this diagnosis are the radiologic findings of an aorta mesenteric artery angle of <25 degrees, compression of the duodenum, and delayed passage of contrast on an UGI series.
• First line therapy is conservative with nutritional support, and enteral is favored over parenteral when possible. Often, until patients are able to take enough calories orally, a nasojejunal feeding tube is utilized. Another option is a small bowel feeding tube distal to the duodenal obstruction. Once weight gain is achieved, patients become more reliant on oral intake. If enteral feeding fails or is not possible, then total parenteral nutrition can be tried.
• Finally, if several months of nutritional support is unsuccessful, then surgery should be considered and several surgical approaches to relieve the SMA obstruction have been described. However, most literature reporting the outcome of such surgery is limited to single institution retrospective studies and variable success is described.
• If there is concern for an eating disorder, a psychiatric consult should be recommended. Finally, there is no role for metoclopramide or amitriptyline in the treatment of SMA syndrome.

Question 21

A 70-year-old man had one 35-mm tubular adenoma in the ascending colon discovered on a recent colonoscopy. The physician performed piecemeal endoscopic mucosal resection (EMR) and clipped the polypectomy site with 4 hemoclips. No other polyps were found in the colon. Which surveillance interval should be assigned to this patient?

A. 3 months

B. 1 year

C. 2 years

D. 3 years

Answer 21

It is recommended to repeat colonoscopy in 3-6 months to assess for local recurrence after piecemeal EMR.

Question 22

A 45-year-old man has had watery diarrhea for many years. He typically has 5-6 stools daily, mostly in the mornings, but sometimes after lunch and dinner. He does not wake at night with diarrhea and has not lost weight. He saw a gastroenterologist before moving to your city 3 years ago and had a full work-up including stool studies, blood work, colonoscopy with biopsies, and upper endoscopy; all were normal, including CT of the abdomen and pelvis. You have him collect a 24-hour stool on 100 gram fat diet. It shows 560 grams of stool, 5 grams of fat. What is the best treatment option?

A. Subcutaneous octreotide weekly

B. Cholestyramine powder

C. Pancreatic enzymes

D. Gluten-free diet

Answer 22

• This is most likely functional diarrhea but may be due to primary bile acid diarrhea (BAD) and thus could respond to cholestyramine. BAD may account for up to 40% of diarrhea-predominant IBS or functional diarrhea and in some cases, is related to a genetic mutation in the normal regulation of bile acids, so that more bile acids reach the colon causing watery diarrhea.
• The volume of stool is not consistent with a secretory diarrhea so octreotide should not be given. The fat content is normal so treatment of pancreatic insufficiency or celiac disease is not indicated.

Question 23

A 55-year-old woman is hospitalized with prerenal azotemia that responds to volume repletion. You are asked to see her in consultation. She tells you that she has been having voluminous diarrhea for months, following a trip to Crater Lake in Oregon. She traveled with several family members, and none of them are sick. She has 6-7 watery, nonbloody stools every day, and 1-2 times a night her diarrhea awakens her from sleep. She has been drinking ample water and sports drink, but still has a hard time staying hydrated and has now has lost 20 lb of weight. She does not have any abdominal pain. Stool cultures have been negative. CT imaging, colonoscopy, and upper endoscopy are all normal. You order a 24-hour stool collection and it shows 1,800 grams of stool, 12 grams of fat/24 hours, Na=119 eEq/L, and K=17 mEq/L, magnesium 17 mEq/L, osmolarity 285 mEq/L, and laxative screen is negative. Which of the following is the most likely diagnosis?

A. Pancreatic insufficiency

B. Factitious diarrhea

C. Idiopathic secretory diarrhea

D. Irritable bowel syndrome

Answer 23

This is a secretory diarrhea with large volume and the low osmotic gap is established by the equation 290 – 2x (Na + K) in stool. In this case, the stool osmotic gap is 290- 2x (119+17) = 3. The increased fat likely reflects the large volume of stool output, rather than maldigestion, as in pancreatic insufficiency or malabsorption, as in mucosal disease. The volume of stool collected is higher than typically seen with IBS, and weight loss and lack of abdominal pain are against IBS. Also, IBS is not typically associated with a sectretory pattern. Factitious diarrhea is less likely given the normal stool osmolarity and magnesium, as well as a negative laxative screen.

Question 24

A 54-year-old man with a history of hypertension, diabetes, coronary artery disease, and recent myocardial infarction about 2 months prior to presentation with resultant left ventricular ejection fraction of 15% presents with the acute onset of severe abdominal pains. He rates the pain 8/10 and diffuse throughout his abdomen. His abdominal exam shows a soft abdomen with some mild tenderness, but no rebound or guarding. The patient undergoes a CT scan that shows mesenteric fat stranding with some ascites. What should be done next to help diagnose this patient?

A. Magnetic resonance angiography

B. Emergent exploratory laparotomy

C. Selective mesenteric angiography

D. Re-review of the portal venous imaging by radiology

Answer 24

This patient has a classic history and imaging of acute mesenteric ischemia (AMI). Given the recent myocardial infarction with reduced ejection fraction, he most likely has a nonocclusive mesenteric ischemia, but this is not completely clear from the history. The patient’s CT scan showed general findings consistent with mesenteric ischemia and his pain is “out of proportion on exam.” In patients who have signs of AMI and there is a CT scan with portal venous contrast already performed, there is evidence to show that calling the radiologist for further review of the original imaging can avoid delay in diagnosis and identify similar information compared to performing a CT angiogram. An MR angiogram is an accurate study, but the time required for this study is extensive and would delay diagnosis, increasing the likelihood of necrosis and a poor outcome. Calling a surgical consult could be helpful, but this patient does not have evidence of necrosis and therefore a surgical intervention is not indicated at this time. Selective mesenteric angiography also could be helpful in diagnosing the etiology of the AMI, but similar to the CT angiogram, a call to the radiologist to re-review the imaging to assess the SMA for patency would the most appropriate next assessment.

Question 25

A 65-year-old woman with a history of metastatic breast cancer on chemotherapy presents with 4 days of worsening abdominal pain, nausea, and vomiting. There is no history of diarrhea or blood in her stool. The patient is febrile (39.1°C), but her blood pressure and heart rate are normal. Physical exam is remarkable for mild tenderness of her abdomen, but no rebound or guarding. The serologic assessment is normal. Portal venous phase CT scan is consistent with thickening of the jejunum with haziness of the mesentery with small ascites and enlargement of the superior mesenteric vein. What is the best initial treatment option for this patient? A. Heparin infusion B. Tissue plasminogen activator C. Surgical embolectomy D. Endovascular thrombolysis E. Papaverine infusion

Answer 25

This patient has the classic presentation of mesenteric venous thrombosis (MVT). Her main risk factor is the active breast cancer and her symptoms are the most commonly seen for MVT. The patient’s imaging also is consistent with MVT, with the dilated superior mesenteric vein being the factor that favors MVT over other forms of mesenteric ischemia. When a patient presents with MVT without peritoneal signs, the first treatment that is most efficacious is a heparin infusion followed by 3-6 months of oral anticoagulation therapy. Tissue plasminogen activator is never indicated in the treatment of MVT. A surgical embolectomy is reserved for patients with peritoneal signs or if the patient has clear signs of necrosis on cross sectional imaging. Endovascular intervention for MVT is reserved for those patients who do not improve with systemic anticoagulation, but do not have peritoneal signs. Papaverine, a vasodilator, is reserved for patients with other forms of mesenteric ischemia.

Question 26

A 62-year-old man underwent screening colonoscopy with resection of a 1.5-cm sessile tubulovillous adenoma from the ascending colon. Three years later, he had a colonoscopy with resection of 2 adenomas (4 and 5 mm in size) from the transverse colon. Five years later, his colonoscopy was normal. When should the next colonoscopy be performed? A. 3 years B. 5 years C. 7 years D. 10 years E. No further colonoscopy is recommended.

Answer 26

According to the 2012 U.S. Multi-Society Task Force recommendations, patients who have advanced findings (adenoma ≥1 cm, adenoma with villous elements or high-grade dysplasia, or 3 or more adenomas) should have a colonoscopy in 3 years. Those with 1 or 2 tubular adenomas with low-grade dysplasia (low-risk findings) should have a repeat colonoscopy in 5-10 years. Those with advanced findings who reach 5 years should stay at 5-year intervals, even when colonoscopy is normal. Those with low-risk adenomas (and no prior high-risk findings) who have normal colonoscopic follow-up at 5 years could return to a 10-year screening interval.

Question 27

The local community health center asked for help in boosting their colorectal cancer screening adherence among average-risk adults. Which of the following approaches would be most likely to result in increased screening participation? A. Placing pamphlets about screening colonoscopy throughout the clinic area. B. Mailing information about screening colonoscopy to average-risk adults. C. Offering screening colonoscopy to average-risk adults at the time of clinic visits. D. Employing electronic health record-linked reminders, mail fecal occult blood testing kits to average-risk adults and follow-up with screening navigation. E. Offering to pay average-risk adults $10 to complete a fecal immunochemical test.

Answer 27

Colorectal cancer screening adherence in the United States is currently well below the 80% target for 2018 (62.4% in 2015). Numerous studies have investigated interventions to improve screening adherence. These interventions range from the patient-level to the provider-level to the system-level. Small-media educational efforts (e.g., pamphlets) have been shown to have limited benefit, though intensive one-on-one education does significantly improve adherence. Studies of financial incentives have had some mixed results, though payments in the range of $10 have been ineffective. There are concerns about the downstream impact of paying individuals to undergone recommended health behaviors, such as screening (e.g., loss of the intrinsic value of screening may lead to a decline in the adoption of future health behaviors). Opportunistic screening approaches have generally been associated with lower colorectal cancer screening adherence than programmatic screening approaches, including electronic health record-linked clinical reminders, mailing of fecal occult blood testing kits and screening navigation. Organizations that employ programmatic screening (e.g., Kaiser Permanente and the Veterans Health Administration) have been able to surpass the 80% screening adherence target through the use of these tools.

Question 28

Which of the following are typical endoscopic features of a sessile serrated polyp? A. Thick vessels surrounding pits B. Tubular and branching pits C. Pedunculated shape **D. Large round dark type “O” pits** E. Predominantly red color when viewed in white light

Answer 28

The Narrow Band Imaging International Colorectal Endoscopic Classification (NICE) and the Workgroup on serrAted polypS and Polyposis (WASP) classifications provide an excellent guide to endoscopic prediction of colon polyp histology. The NICE classification describes criteria to differentiate conventional adenomas from serrated class lesions (sessile serrated polyps and hyperplastic polyps). Large open pits, irregular shape, indistinct edges, and a “cloud-like” appearance to the polyp surface are the WASP criteria that distinguish sessile serrated polyps from hyperplastic polyps.

Question 29

A 42-year-old man is diagnosed with stage II adenocarcinoma of the **upper rectum**. He is seeing a multidisciplinary team to discuss treatment options. Which of the following is associated with the lowest risk of local recurrence of cancer? A. Transanal endoscopic microsurgery B. Neoadjuvant chemoradiation followed by surgery with total mesorectal excision C. Transanal excision D. Abdominoperineal resection

Answer 29

* Rectal cancer poses a distinct clinical challenge, due to its _higher propensity for local recurrence than colon cancer._ Despite advances in technique and interest in less invasive treatment options than radical surgery, local excision options such as _transanal endoscopic microsurgery or transanal excision are associated with increased risk of local recurrence_. * **Neoadjuvant chemoradiation followed by surgery with total mesorectal excision is associated with recurrence rates of about 2%.** * Abdominoperineal resection (APR) is usually considered in cases where the cancer is very low in the rectum (typically within 3 cm of the anal verge) and is not anal-sparing; given the location of the cancer in this case, APR is not indicated.

Question 30

A 57-year-old man presents with a history of a prior C. difficile infection. At the time of diagnosis, he was treated with a 10-day course of vancomycin. While on therapy, his diarrhea resolved. The patient now presents to your office with 3 days of diarrhea. When considering the differential diagnosis for his clinical presentation, you recall that the most recent American College of Gastroenterology Guideline defines a recurrence of Clostridium difficile infection by symptoms and a positive test after a successfully treated initial infection within what time frame? A. 1 day B. 8 weeks C. 26 weeks D. 52 weeks

Answer 30

Recurrence is defined as the recurrence of symptoms after a successful initial treatment course for C. difficile. This can occur days after completing the antibiotic course or weeks later. Eight weeks is the window of recurrence. If there is no recurrence of symptoms by 8 weeks after completing therapy, the patient has successfully cleared this infection. Episodes that occur several months or years later are not recurrent infection, but rather new initial infections.

Question 31

How do you measure adenoma detection rate (ADR)? A. The proportion of screening colonoscopies performed by a physician that detect at least 1 histologically confirmed colorectal polyp. **B. The proportion of screening colonoscopies performed by a physician that detect at least 1 histologically confirmed colorectal adenoma or adenocarcinoma.** C. The proportion of all colonoscopies performed by a physician that detect at least 1 histologically confirmed colorectal polyp. D. The proportion of all colonoscopies performed by a physician that detect at least 1 histologically confirmed colorectal adenoma or adenocarcinoma.

Answer 31

Adenoma detection rate is measured as the proportion of screening colonoscopies performed by a physician that detect at least 1 histologically **confirmed colorectal adenoma or adenocarcinoma**. The polyp detection rate (PDR) is the number of patients with ≥1 polyp removed during screening colonoscopy in patients aged ≥50 years.

Question 32

A 32-year-old man is seen in your clinic to discuss colon cancer screening. He is very concerned because his 63-year-old father was just diagnosed with colon cancer and he was told he needed a colonoscopy "early." Which of the following is the correct age to initiate screening? A. Now B. 40 C. 45 D. 53 E. 55

Answer 32

Patients are often concerned about family members with colon cancer and how it may affect their own screening. Outside of a family history suggestive of polyp syndromes (e.g., Lynch, FAP, serrated polyposis syndrome, etc), the U.S. Multi-Society Task Force on Colorectal Cancer recently released updated guidelines on screening patients with a family history of a first-degree relative of colorectal cancer OR a documented advanced adenoma (**lesion ≥10 mm or having high-grade dysplasia or villous elements)**, stratifying patients based on what age the relative was diagnosed. If one first-degree family member was \< age 60 at diagnosis OR there are 2 first-degree family members at any age, the patient should start screening at age 40 or 10 years earlier than the youngest family member’s age of diagnosis, whichever comes first, and continue screening at least every 5 years. However, if the first-degree family member was \> age 60, screening should start at age 40, but then intervals can be the same as average-risk individuals. Hy-Vee 10

Question 33

A 65-year-old man with Crohn’s colitis was seen for a surveillance colonoscopy. The patient was asymptomatic on maintenance infliximab. The endoscopist used standard-definition white light colonoscopy and took 30 random biopsies throughout the colon. Submission to pathology showed that 1 of the samples from the left colon at 50 cm had low-grade dysplasia, and was confirmed by a second GI pathologist. What should the endoscopist do? A. Colonoscopy with narrow banding imaging B. Colonoscopy with chromoendoscopy C. Hemicolectomy D. Colonoscopy with high-definition white light rather than standard-definition white light

Answer 33

The initial management step in patients with invisible low-grade or high-grade dysplasia would be to refer the patient to an experienced endoscopist with chromoendoscopy expertise. Careful chromoendoscopy to identify suspected dysplastic lesions may help in deciding whether to perform localized endoscopic resection or refer for colectomy. Further confirmation by an expert GI pathologist in IBD and a second pathologist is recommended before making a management decision.

Question 34

Which of the following has been shown to have the greatest specificity for colorectal cancer or advanced adenomas with one-time screening? A. CT colonography B. Fecal immunochemical test C. Methylated septin 9 plasma testing D. Multitarget stool DNA testing E. Capsule colonoscopy

Answer 34

Fecal immunochemical testing has the highest specificity of any of the listed screening tests, at approximately 95%. This results in fewer false-positive results on one-time testing compared to the other tests. However, as FIT is recommended annually, the programmatic specificity (e.g., over 3, 5, or 10 years) is expected to fall compared to the specificity of one-time application of the test. CT colonography has a reported specificity of 67-98%, while methylated septin 9 has a specificity of 80%, multitarget stool DNA testing has a specificity of 86.6%, and capsule colonoscopy has a specificity of 82%.

Question 35

A 42-year-old woman presents to the emergency department with 5 hours of worsening diffuse abdominal tenderness. Her history is remarkable for 4-months of intermittent abdominal pain, intermittent hematochezia, and a 20-lb weight loss. On physical examination, the abdomen is distended and markedly tender with guarding. Her laboratory examination reveals WBC 14.5 x 109/L and normal electrolytes and coagulation panel. CT scan reveals dilated loops of bowel (10 cm at the cecum) proximal to a locally infiltrating mass in the ascending colon with nonspecific lymphadenopathy in the vicinity of the mass. What is the most appropriate next step in this patient's management? A. Emergency colonoscopic decompression B. Rectal tube placement C. Colonoscopy with a self-expanding metal stent placement (SEMS) D. Surgery consultation

Answer 35

If there is no contraindication to surgery, surgical management should be sought because technical and clinical success rates associated with proximal colonic obstruction are higher with surgery as compared with SEMS. In the setting of an obstructing colonic mass, it remains controversial whether a preoperative SEMS can reduce mortality, complication rate, or stoma requirement. A systemic review and meta-analysis showed SEMS as a bridge to surgery for obstructed left-sided colon cancer decreased the incidence of primary stoma rates and anastomotic leakage, but it failed to show benefits on mortality. It is also important to consider that SEMS can result in overt and/or silent perforation.

Question 36

A 38-year-old man met with a geneticist to discuss a recent diagnosis of Lynch syndrome after finding a mismatch repair deficiency on a large polyp during colonoscopy. For which of the following extra-colonic cancers associated with Lynch syndrome is he most at risk? A. Brain B. Urinary tract C. Hepatobiliary D. Pancreas

Answer 36

* Lynch syndrome carries a high risk of developing extra-colonic cancers and patients should undergo surveillance studies. In women, **endometrial cancer is the most common extrra-colonic malignancy,** which should be screened on an **annual basis with transvaginal ultrasound and pelvic exam with endometrial sampling**. * In men, **prostate and urinary tract are the highest extra-colonic malignancies**. Patients with Lynch syndrome have up to a **25% increase in the risk of developing urinary tract malignancy**. * There is also an increased risk of developing brain, hepatobiliary, and pancreatic cancer which can be seen in up to 4% of Lynch syndrome patients. Women with Lynch syndrome with MLH1 or MSH2 mutation have a 54% risk of developing endometrial cancer, and endometrial sampling is recommended annually starting at age 30-35. Elective hysterectomy could be considered when childbearing has been completed, if desired.

Question 37

A 78-year-old man with a history of leukemia on chemotherapy, presents with right-sided abdominal pains and nonbloody diarrhea. The pains are 6/10 and nonradiating and he is having 4-6 Bristol 7 (watery) stools daily with progressively worsening pain and diarrhea over the last week. He has not had any recent sick contacts or overseas travel. Upon presentation to the ER, the patient is noted to be hypotensive (85/60) and tachycardic (105 beats/min). His exam is remarkable for significant RLQ tenderness without rebound or guarding. He undergoes a CT scan showing cecal inflammation but a normal appearing appendix. His serologic assessment shows a WBC of 2.0x103/mL with 50% PMN. The patient is given IVF and started on broad-spectrum antibiotics. What is the most likely diagnosis? A. Colonic ischemia B. Tuberculosis C. Crohn’s disease D. Neutropenic enterocolitis E. CMV colitis

Answer 37

* The patient's presentation is classic for neutropenic enterocolitis including the underlying diagnosis of **leukemia, being actively on chemotherapy, and presenting with abdominal pain.** * The most common location for colitis in a patient with neutropenic enterocolitis is the **right colon and these patients frequently present with signs of sepsis.** * Colonic ischemia is less likely, as colonic ischemia of the right colon usually involves the cecum and ascending colon. * Tuberculosis presents with abdominal pain and watery diarrhea but is _not typically associated with sepsis at presentation and usually occurs in the setting of other risk factors such as international travel_. * Crohn’s disease does not usually present with an acute onset like this presentation and the WBC is not usually low in patients with Crohn’s disease. * CMV colitis is possible in this patient, but the presentation is most consistent with neutropenic enterocolitis.

Question 38

A 73-year-old woman presented for screening colonoscopy and was found to have a T1 rectal cancer. When given the choice between a low-anterior resection and a transanal endoscopic microsurgery, she elected for the transanal approach. Following the resection, the histology confirmed T1 disease. What is the next recommended surveillance technique and time point given this patients resection? A. Flexible sigmoidoscopy or EUS in 6 months B. Flexible sigmoidoscopy or EUS in 1 year C. Colonoscopy in 3 years D. Colonoscopy in 5 years

Answer 38

The risk of rectal cancer recurrence is significantly reduced via surgical procedures such as a low anterior resection of the rectum and mesorectum fascia. Newer surgical techniques such as transanal endoscopic surgery and transanal excision offer local excision with lower morbidity, mortality and better quality of life, however there is a higher risk of local recurrence. Therefore, USMSTF guidelines recommend flexible sigmoidoscopy or EUS every 3-6 months for 2-3 years in addition to colonoscopy 1 year, 4 years, and 9 years after surgery or perioperative clearance colonoscopy.

Question 39

A 52-year-old average-risk woman was seen for colonoscopy and was diagnosed with stage III adenocarcinoma of the descending colon. She underwent segmental colectomy, and molecular testing revealed that the tumor was microsatellite stable (MSS) and without BRAF mutations. Which of the following outcomes would you predict regarding this patient’s prognosis and response to treatment? A. Worse prognosis than a patient with MSS colon cancer with mutant BRAF B. Good response to anti-EGFR therapy using cetuximab C. Worse prognosis than stage-adjusted microsatellite instability (MSI) colon cancer D. Increased risk of endometrial cancer

Answer 39

The molecular features of colorectal cancer (CRC) are strongly associated with several prognostic and predictive features. In general, MSI CRC has a more favorable prognosis than MSS CRC, regardless of whether the implicated pathway is the Lynch (mutator) or CIMP (serrated) pathway. BRAF mutation is associated with worse prognosis in MSS CRC, particularly advanced stage (III or IV) cancer, and these CRCs (MSS/mutant BRAF) do not respond to anti-epidermal growth factor receptor therapy such as cetuximab. Endometrial cancer is one of the Lynch syndrome (LS)-associated malignancies, but LS is characterized by MSI, which is not a feature of this CRC.

Question 40

A 65-year-old average-risk man undergoes colonoscopy for evaluation of constipation, intermittent hematochezia, and abdominal pain. He has an obstructive mass in the proximal sigmoid colon which cannot be traversed. Biopsies reveal adenocarcinoma. Metastatic work-up is negative. He undergoes urgent partial colectomy and recovers uneventfully. Which of the following do you recommend for follow-up? A. Colonoscopy in 3 years B. Colonoscopy in 1 year C. Colonoscopy in 3-6 months D. EUS every 6 months for 2 years

Answer 40

Complete high-quality colonoscopy is critical to exclude synchronous cancer and find and resect polyps in patients with CRC. The prevalence of synchronous tumors ranges from 0.7% to about 7%. Clearing colonoscopy is generally performed preoperatively; however, in some cases, malignant obstruction precludes safe completion of the procedure. In such cases, the procedure can be deferred for 3 to 6 months postoperatively. CT colonography is the best alternative to colonoscopy to exclude synchronous neoplasia, and can also be considered in this situation.

Question 41

A 63-year-old woman is diagnosed with localized rectal cancer and undergoes a transanal resection. What next type of surveillance listed below is most appropriate? A. Colonoscopy in 1 year B. Colonoscopy in 3 years C. CT colonography in 3-6 months **D. Flexible sigmoidoscopy in 3-6 months** E. Endoscopic ultrasound (EUS) in 1 year

Answer 41

Surveillance differs between colon and rectal cancer because of the latter’s higher rate of local recurrence. More than 80% of anastomotic recurrences involve rectal or distal colon cancer. Recurrence rate depends on accurate preoperative staging, neoadjuvant chemoradiation for locally advanced disease, and surgical technique and is decreased with total mesorectal excision in which the rectum and mesorectal fascia are resected en bloc by sharp dissection. Transanal excision or transanal endoscopic microsurgery are associated with higher local recurrence rate than radical surgery. The recent USMSTF Guidelines on surveillance after colorectal cancer recommend that localized rectal cancer treated with transanal local excision or endoscopic submucosal dissection be subjected to surveillance with local surveillance of the anastomotic site with flexible sigmoidoscopy or EUS every 3-6 months for the first 2-3 years after surgery. There are insufficient data to determine which modality is superior. Patients should also undergo recommended colonoscopic surveillance for metachronous neoplasia at 1, 3, and 5 years.

Question 42

The most recent U.S. Preventive Services Task Force guidelines on screening for colorectal cancer recommend against routine screening for colorectal cancer starting after which age? A. 70 years B. 75 years C. 80 years D. 85 years

Answer 42

The USPSTF recommends screening for colorectal cancer using fecal occult blood testing, sigmoidoscopy, or colonoscopy in adults, **beginning at age 50 years and continuing until age 75 years.** The risks and benefits of these screening methods vary. The USPSTF recommends against routine screening for colorectal cancer in adults 76 to 85 years of age. There may be considerations that support colorectal cancer screening in an individual patient.

Question 43

An obese 70-year-old man was seen for colonoscopy after a positive fecal immunochemical test. His colon proved redundant and the ileocecal valve was never visualized. A CT colonography revealed a 2-cm sessile polyp in the mid-ascending colon. When the repeat colonoscopy was attempted, what would be the most important technical change to make in order to achieve cecal intubation? A. Use of an overtube B. Having the patient lose weight C. Use of a pediatric colonoscope D. Having 2 assistants apply abdominal pressure E. Filling the colon with water, rather than gas, during insertion

Answer 43

Standard instruments are stiffer than pediatric colonoscopes. Thus, standard instruments are the better choice in redundant colons. Pediatric colonoscopes are preferred when angulated and narrowed sigmoid colons are the cause of failed colonoscopy. Filling the colon with water, rather than gas, keeps the colon shorter and narrower. Further, gas causes the sigmoid to move into the midabdomen and the sigmoid turns to become more acute. Water filling causes the sigmoid to lie in a straight line in the left lower quadrant. Water filling was found to be the single most useful technical step to change when a redundant colon has previously prevented cecal intubation.

Question 44

A 42-year-old man has had refractory constipation for 5 years. He was found to have a redundant sigmoid colon and underwent a sigmoidectomy. This did not improve his symptoms. A radiopaque marker study showed retention of markers in the colon after 5 days and he underwent total abdominal colectomy with ileorectal anastomosis. This did not relieve his symptoms either. What is the most likely explanation for his ongoing constipation symptoms? A. Unappreciated chronic intestinal pseudo-obstruction B. Dysautonomia C. Rectal cancer D. Functional rectal outlet disorder E. Depression

Answer 44

At one time, colon resection was looked at as a cure-all for refractory constipation. Unfortunately, up to one-third of patients with constipation have functional rectal outlet issues and these patients do not respond to surgery and other treatments as well as patients without rectal outlet problems. These problems include dyssynergic defecation and transient anatomic problems, such as perineal descent, rectocele, pelvic organ prolapse, and anterior wall rectal ulcer syndrome. These alternate diagnoses must be considered in patients with abnormal digital rectal examinations, in those who do not respond to empiric therapy, and in anyone being considered for colectomy for constipation before the surgery is done. The other problems listed may also produce suboptimal results after colectomy, but are less likely to occur.

Question 45

A 58-year-old man who had a normal colonoscopy 8 years prior to presentation is seen in your office with 6 months of constipation. His baseline bowel habits included 1 formed stool daily, but 6 months ago, he started to have the sensation of incomplete evacuation and increased straining to move his bowels. He denies anal pain or rectal bleeding. Over the prior 8 weeks, he has had on average 4 bowel movements per week. He takes no prescription medications. The patient initially tried fiber supplements, bisacodyl, and a polyethylene glycol laxative, but has only had temporary relief with each treatment. What is the next most appropriate step in his evaluation? A. Digital rectal examination B. Anoscopy and colonoscopy C. Anorectal manometry with assessment of recto-anal inhibitory reflex

Answer 45

* A thoughtful digital rectal examination is the first step in assessing a patient with chronic constipation. The physician should comprehensively assess the perianal skin for evidence of dermatitis or stool residue that might suggest fecal incontinence. * By spreading the buttocks apart, anal fissures may also be visualized. * Next, the physician should place the gloved examining finger into the anal canal and note any tenderness, assess the muscle bulk, and after a moment to allow baseline conditions to resume, assess anal sphincter tone. * The examiner should then ask the subject to squeeze the sphincter shut as if trying to prevent a bowel movement in order to assess sphincter squeeze strength. * Following this, attention should shift to the rectal contents with consideration for the presence of stool in the rectal vault. If stool is present, what is its consistency and bulk? Is a fecal impaction present? The examiner should then sweep their finger around the surface of the rectum to assess for a rectocele or impingement of the rectum by the uterus or cervix. * A high quality rectal exam should then palpate the pelvic floor through the wall of the rectum, paying attention to the puborectalis muscle located transversely posterior and trailing off laterally. The provider should assess for tenderness of this muscle. Next, the examiner should ask the patient to bear down as if having a bowel movement. This should be accompanied by relaxation of the puborectalis muscle and the anal sphincter muscle. If these muscles contract instead, the provider should consider dyssynergic defecation that might be contributing to the constipation. * Pelvic descent also may be appreciated during this maneuver. Digital rectal examination thus provides a good assessment regarding some common pathophysiological mechanisms for constipation. The other tests listed may be important following a high-quality rectal examination.

Question 46

A 65-year-old man with a **history of head and neck cancer** is referred to you after a surveillance PET scan demonstrates **incidental update in the right colon.** negative screening colonoscopy 4 years ago. Reviewing the procedure note, the appendiceal orifice was photographed and the Boston Bowel Preparation Score was 8. Which of the following statements is accurate? A. The PET scan finding is an indication for colonoscopy at this time. B. A BBPS of 8 essentially excludes that a lesion was missed during the colonoscopy 4 years ago. C. Increased PET scan activity in the right colon is common and does not warrant further evaluation. D. A colonoscopy should be performed if there is additional support for such an intervention such as a positive FIT test or positive stool DNA test.

Answer 46

* **A PET scan that is positive for the colon is highly sensitive for a pre-malignant or malignant lesion and should be followed up with a colonoscopy.** * In one large retrospective study of patients undergoing PET scan who were found to have incidental colonic update, _38% had pre-malignant lesions (many of which were advanced) and 14% had colorectal cancer_. All those found to have colon cancer had a focal pattern of [18 F]FDG uptake. * remains the risk of missing a colon lesion with colonoscopy. A systematic analysis reviewed back to back colonoscopy studies and found colonoscopy miss rates of 2.1% for adenomas \>10 mm, 13% for adenomas 5-10 mm, and 26% for adenomas 1-5 mm. * **Regardless of the preparation adequacy, a positive colonic finding on PET scan warrants repeating the colonoscopy.**

Question 47

Tier 1 colorectal cancer screening tests? B. Colonoscopy every 10 years or annual FIT

Answer 47

The U.S. Multi-Society Task Force ranked the current colorectal cancer screening tests as shown below: ***Tier 1 Colonoscopy every 10 years Annual fecal immunochemical test*** Tier 2 CT colonography every 5 years FIT-fecal DNA every 3 years Flexible sigmoidoscopy every 10 years (or every 5 years) Tier 3 Capsule colonoscopy every 5 years Available tests not currently recommendedSeptin 9 The tier 1 tests represent the cornerstone of CRC screening today. In organized screening programs, such as health maintenance organizations, offering programmatic screening with FIT is often offered as the primary screening modality. However, colonoscopy can be offered as an alternative for patients and providers who prefer this option. In the opportunistic screening environment, which is common in the United States, colonoscopy is often preferred as the infrastructure to help ensure annual performance if FIT is not available. The U.S. Multi-Society Task Force recommends focusing on these 2 test options based upon their performance features, costs and practical considerations. Offering patients a choice has been shown to be associated with increased adherence with screening, though longitudinal adherence with FOBT declines in the absence of navigation. The tier 2 tests are also appropriate for colorectal cancer screening, but they each have disadvantages relative to the tier 1 tests. Capsule colonoscopy was categorized as a tier 3 test due to limited evidence and current obstacles to its use, including the need for a more extensive bowel preparation than for colonoscopy. In addition, it is logistically very difficult to perform a same-day colonoscopy after a capsule colonoscopy.

Question 48

A 32-year-old man with human immunodeficiency virus (HIV) diagnosed a year ago presented with generalized weakness, fever, and chills for 1 week. He was not taking antiretroviral therapy. Physical exam was significant for **multiple nonpruritic purplish to red skin lesions on the trunk and upper and lower extremities**.Hemoglobin level was 8.2 gm/dL (normal: 14-17 gm/dL) and stool guaiac was positive. **CD4 count was \<20** cells/mm3 (normal: 500-1,200 cells/mm3). Endoscopy showed **multiple gastric and duodenal lesions** [FIGURES A and B]. What is the appropriate next step in the management? A. Systemic chemotherapy B. Antiretroviral therapy C. Observation D. Combined antiretroviral and systemic chemotherapy

Answer 48

* Kaposi sarcoma - HIV+low CD4+skin lesions * gastric and duodenal involvement, **extent of the tumor (T).** * T0 -limited to skin or minimal oral cavity lesions * T1 -poor prognosis,patients with lymphedema, more extensive oral cavity involvement, or other visceral disease as in this patient * Patients who are immunocompromised and who have severe systemic disease are also considered to have a poor prognosis. These patients are better treated with combined **antiretroviral and systemic chemotherapy.** * ART alone ok with limited Kaposi sarcoma, nonimmunocompromised and no systemic symptoms like weight loss or fever and chills. * **Observation alone not appropriate in any case of Kaposi/HIV**

Question 49

45M first screening colonoscopy. +FH CRC. The endoscopist identifies a **5-mm sessile lesion in the sigmoid colon** with endoscopic features highly suggestive of adenoma, including irregular surface pattern, variable blood vessels surrounding pits, and a **valley sign using narrow band imaging** [FIGURE]. Which polypectomy technique is recommended? A. Hot large capacity forceps polypectomy B. Hot snare polypectomy C. Cold large capacity forceps polypectomy D. Cold snare polypectomy

Answer 49

* The **valley sign is insensitive but highly specific for conventional adenoma in diminutive polyps.** Cold snare polypectomy is recommended for diminutive colorectal polyps ≤5 mm in size. * Hot forceps for diminutive small polyp resection can affect pathological interpretation and can cause deeper tissue injury, resulting in postpolypectomy bleeding, coagulation syndrome or perforation. * Cold forceps have shown high rates of incomplete resection (9-61%). Risk of incomplete resection can be reduced with cold snare (79%) or large capacity forceps (52%).

Question 50

Ergonomics in endoscopy

Answer 50

* The optimal bed height will allow for neutral spine and shoulder/arm posture, as in FIGURE C. If the bed is too low, as in FIGURE A, the trunk is flexed, unnecessarily loading the spine and potentially resulting in back strain. If the bed is too high, as in FIGURE B, the shoulders are abducted resulting in increased deltoid and trapezius muscle activity, potentially leading to shoulder and neck strain. To achieve a neutral posture for the range of endoscopists, the endoscopy gurney should be adjustable to allow holding of the endoscope between elbow height and 10 cm below elbow height to **minimize forward flexion of the back and shoulder abduction**. To accommodate the elbow height of the 5th percentile female to the 95th percentile male, the examination bed should be adjustable between **85 and 120 cm.** * The monitor is too high, requiring cervical neck extension to view the monitor screen, and is the most likely etiology of the endoscopist’s neck pain. To attain neutral neck posture, the monitor should be placed directly in front of the endoscopist while in the position of work, to avoid lateral rotation of the neck. The monitor height should be adjustable to accommodate a neutral neck posture for the range of heights of endoscopists, from the 5’ female endoscopist to the over 6’ male endoscopist, taking into account that at rest, the **eyes naturally assume a straightforward and downward cast line of sight**. To accommodate the 5th percentile female to the 95th percentile male eye height, the monitor should be adjustable such that the center of the monitor can be adjusted between **93 to 162 cm above the floor.**

Question 51

A 55-year-old woman surveillance colonoscopy. She recently relocated from out of state and was unable to provide her outside records but stated that she had a colonoscopy with removal of a **“large benign polyp” 6 months prior**. She was recommended to have a repeat colonoscopy within **6 months to reassess the polypectomy site**. You perform the colonoscopy and the polypectomy site was identified and appeared as follows [FIGURE A and B]. What is the next step for the tissue seen at the scar site? A. No intervention B. Cold snare C. Cold forceps D. Endoscopic mucosal resection

Answer 51

* This "polyp" is a clip artifact, not a recurrence. Clip artifact is characterized by a **nodular elevation of the mucosa with a normal pit pattern** and can occur **with or without residual clips.** * Prophylactic clip closure and the presence of residual clips are associated with clip artifact.

Question 52

A 68-year-old man presents with a history of recurrent bleeding of unknown etiology. Small bowel bleeding is suspected to be the source after a negative second-look endoscopy. Capsule endoscopy reveals multiple small bowel angioectasia as seen in the figure. Which of the following is the correct statement regarding evaluation of the small bowel? A. MR imaging is preferred over CT imaging in the majority of cases. B. If capsule endoscopy is negative, there is no indication to proceed with deep enteroscopy or cross-sectional imaging. C. Small bowel barium studies should not be performed for evaluating a patient with suspected acute small bowel bleeding.

Answer 52

* Multiple studies have shown that the diagnostic yield of small bowel barium studies is low compared to capsule endoscopy, cross-sectional imaging, and deep enteroscopy. * If capsule endoscopy is negative but there is still a high index of suspicion, then complementary testing with cross-sectional imaging and/or deep enteroscopy should be strongly considered. * This is partly due to the **potential miss rate of single mass lesions with capsule endoscopy**. * **CT imaging is preferred over MR imaging** for suspected small bowel bleeding. MR can be considered in patients with contraindications for CT or to avoid radiation exposure.

Question 53

BPPS score

Answer 53

Rate the colon bowel preparation quality on withdrawal after washing is performed. A priori, the developers recommended that a score of less than 5 corresponds to an inadequate bowel preparation.

Question 54

A 65-year-old man is referred for surveillance colonoscopy. He had a **12-mm adenomatous polyp in the sigmoid colon 3 years ago**. The patient has a history of coronary artery disease and underwent cardiac catheterization with coronary stent placement 7 years ago, and again 13 months ago. During the last intervention drug-eluting stents were placed. He completed 1 year of dual antiplatelet medications last month. Per his cardiologist, he is supposed to continue on clopidogrel indefinitely. What is the recommended approach to handling periprocedural antithrombotic agents? B. Hold clopidogrel for 5-7 days prior to the colonoscopy and restart the medication following the procedure. D. Hold clopidogrel and change to aspirin 5 to 7 days prior to the planned procedure. Remove any polyps that you may find. Change back to clopidogrel after the procedure.

Answer 54

* This patient has an increased risk of coronary stent occlusion and per his cardiologist should be continued on antiplatelet agents. Clopidogrel increases bleeding risk. In contrast, **aspirin does not increase the risk of severe bleeding complications.** For patients who need to continue on an antiplatelet agent, it is therefore recommended to **switch from clopidogrel to aspirin during the periprocedural period.** * high risk for polyps again- **colonoscopy w polyp resection is high-risk procedure w/ inc risk of postprocedure bleeding**

Question 55

Which of the following situations would necessitate antibiotic prophylaxis? A. EUS-FNA of a solid 3-cm submucosal lesion in the gastric cardia B. EGD and colonoscopy with likely polypectomy in a patient with a history of ascending aortic aneurysm repair with synthetic vascular graft 3 years ago C. Percutaneous feeding tube placement D. EGD in a patient with history of mitral valve prolapse E. ERCP with stenting and complete drainage in a patient with malignant biliary obstruction without evidence of cholangitis

Answer 55

* high risk for bacteremia or local infection: 1. esophageal dilation 2. sclerotherapy of varices 3. instrumentation of obstructed bile ducts 4. EUS-FNA of **cystic lesions** 5. PEG * Patient factors need for prophylactic antibiotics: * neutropenic patients (ANC \<500 cells/mm3) * those with advanced hematologic malignancies * cirrhosis with concurrent GI bleeding, or * synthetic vascular grafts within 6 months of placement. * Currently, there are **no cardiac conditions that warrant prophylaxis** unless the patient has a documented infection at time of procedure.

Question 56

66M BRBPR. PMH OA, CAD w/ **drug-eluting coronary stent 2 months prior.** He denies abdominal pain, nausea, vomiting, or chest pain. His medication regimen includes **naproxen 3 times per week**, **clopidogrel 75 mg daily, aspirin 81 mg daily,** hydrochlorothiazide 25 mg daily, metformin 500 mg twice daily, and simvastatin 40 mg daily. Laboratory studies reveal: Hemoglobin 10.5 g/dL (normal: 14-17 g/dL) Blood urea nitrogen 32 mg/dL (normal: 8-20 mg/dL) Alanine aminotransferase (ALT) 34 U/L (normal: 0-35 U/L) INR 1.2 (normal: \<1.5) An upper endoscopy was performed without significant findings. Following rapid colon preparation via nasogastric tube, colonoscopy is notable for an actively bleeding sigmoid diverticulum. Two clips were optimally placed at the base of the bleeding diverticulum, with complete hemostasis. Which of the following is the most appropriate management of this patient's antiplatelet therapy? _{A. Aspirin and clopidogrel should be resumed in 2 weeks.} **B. Aspirin and clopidogrel should be resumed immediately.** C. Aspirin should be resumed, but clopidogrel should be held for 2 weeks. D. Clopidogrel should be resumed, but aspirin should be held for 2 weeks.

Answer 56

* In this specific case, the endoscopist is confident that the endoscopic bleeding control measures were optimal and, therefore, DAPT **should be resumed immediately.** In patients with **established high-risk cardiovascular disease and a history of lower gastrointestinal hemorrhage, aspirin used for secondary prevention should not be discontinued**. In patients on non-aspirin antiplatelet therapy, **treatment should be resumed as soon as possible and at least within 7 days** based on multidisciplinary assessment of cardiovascular and GI risk and the adequacy of endoscopic therapy.

Question 57

You are performing a detailed withdrawal on a patient for surveillance colonoscopy and are in the sigmoid colon. The **insertion was very difficult and required multiple position changes and manual pressure to reach the cecum.** There was already a **2-cm flat polyp removed from the ascending colon with a hot snare**. Given the length of the procedure, the patient has developed some spasm requiring extra insufflation of air. Your nurse tells you the patient is becoming **bradycardic with HR 30-35 beats/min and hypotensive with a blood pressure of 75/40 mmHg**. What is the best immediate next step? A. Stop the procedure immediately and withdraw the scope; a perforation has likely occurred at a tight flexure. B. Stop the procedure immediately and withdraw the scope; a perforation has likely occurred at the polypectomy site. C. Reinsert the scope to the cecum and quickly examine for a possible site of perforation. D. Place patient into the Trendelenburg position, while reinserting the scope to the transverse colon and removing as much air as possible, while reassessing the patient’s clinical status. E. Call a code.

Answer 57

* difficult and prolonged colonoscopy, multiple complications * **Trendelenburg position will help increase venous return to the heart**, **increasing cardiac output, and vital organ perfusion.** * The prolonged case and spasm requiring excessive use of air insufflation with associated bradycardia should prompt consideration of a **vasovagal reaction, risk factors- higher doses of sedation and presence of moderate-severe diverticulosis** * Additionally, the **use of air insufflation over CO2 or water infusion has been associated with higher rates of pain and vagal reactions**. * By immediately decompressing the colon with air removal, it may be possible to help stabilize the patient and avoid a true emergency.

Question 58

A 45-year-old man is referred to you from his primary care provider for consideration of upper endoscopy evaluation. He has a prior history of significant alcohol use but reports quitting alcohol completely about 8 months ago. He denies any history of vomiting blood or blood in his stool, and has never had complications such as ascites, hepatic encephalopathy, or jaundice. On exam, there is no scleral icterus or jaundice and abdominal exam reveals a flat abdomen with normal liver and spleen size on palpation. Approximately 1 year ago, his laboratory test results were notable for: AST 55 U/L (normal: 0-35 U/L) ALT 26 U/L (normal: 0-35 U/L) Platelets **150,000 x 10(9)/L (normal: 151-355 x 10(9)/L)** Bilirubin - normal Albumin - normal Today, his test results are: AST 40 U/L ALT 35 U/L Platelets **175,000 x 10(9)/L** Bilirubin - normal Albumin - normal Abdominal ultrasound demonstrates mildly enlarged liver, with smooth liver edge, and parenchymal echogenicity suggestive of hepatic steatosis. Transient elastography examination today demonstrates liver stiffness measurement of **15kPa.** He has never undergone an EGD or colonoscopy. What would you do next? A. Start propranolol. B. Schedule an EGD. C. Start carvedilol. D. No intervention needed.

Answer 58

* AASLD- patients with chronic liver disease * liver stiffness measurement of **\<20 kPA on transient elastography and** * **platelet count of \>150,000 x 10 (9)/L have very low probability (\<5%) of high risk varices, and thus EGD variceal screening can be circumvented**

Question 59

A woman who was 14 weeks pregnant presented for lower GI bleeding. An urgent colonoscopy was needed and she had elected to have conscious sedation. Which drug is preferred for providing moderate sedation? A. Fentanyl - cat C, not teratogenic but harmful to fetus in animal models **B. MePeridine - cat B, safe, no teratogenicity,** may cause problems with fetal cardiac function, it does not lead to fetal distress "Me**PREG**nidine C. Morphine - crosses BB barrier much quicker, not preferred D. Diazepam - cat D, Chronic diazepam intake during pregnancy can be associated with cleft palate and neuropsychiatric disorders. Midazolam has not been associated with congenital abnormalities and is the benzodiazepine of choice with meperidine but should be avoided in the first trimester, if possible.

Answer 59

Much of the important information and guidance for sedation in pregnancy can be gleaned from the ASGE’s “Guidelines for endoscopy in pregnant and lactating women.”

Question 60

Which one of the following patient factors is an established predictor of a poor bowel preparation? A. English-speaking B. Lower socioeconomic status C. Younger age D. Female sex

Answer 60

* **male sex** * **older age** * **lower socioeconomic status** * **non-native English speakers**

Question 61

Which of the following has been shown to reduce the risk of interval colorectal cancer? A. Adenoma detection rate (ADR) alone B. Withdrawal time alone C. Both adenoma detection rate and withdrawal time D. Use of narrow-band imaging

Answer 61

* Both higher ADR and longer withdrawal time - dec int cA * Not NBI