NYACP Board Review Question of the Week
Every other Tuesday, NYACP members are sent a Board Review Question from ACP's MKSAP 18 to test professional knowledge and help prepare for the exam. Participant totals and answer percentages are distributed on the first Thursday of the month in IM Connected, the Chapter's eNewsletter, and are also published on this page.
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April 22, 2025
MKSAP 19 Gastroenterology & Hepatology, Question 19
A 68-year-old woman is evaluated in the emergency department for sudden-onset, crampy, left- lower-quadrant abdominal pain followed several hours later by passage of bright red blood per rectum. She has hypertension and hyperlipidemia. Current medications are lisinopril and simvastatin.
On physical examination, vital signs are normal. Abdomen is soft and nondistended, with left-lower- quadrant tenderness and no rebound or guarding. Anorectal examination shows scant bright red blood in the rectal vault.
Laboratory testing shows a leukocyte count of 12,000/μL (12 × 109/L) and a blood urea nitrogen level of 24 mg/dL (8.5 mmol/L); other routine laboratory results are normal.
Abdominal and pelvic CT scan shows only segmental thickening of the descending and sigmoid colon.
Which of the following is the most likely diagnosis?
A. Acute diverticulitis
B. Clostridioides difficile infection
C. Colonic ischemia
D. Ulcerative colitis
Responses Received from Members (767 Responses):
The Correct Answer is: C. Colonic ischemia
Educational Objective:
Diagnose colonic ischemia.
The most likely diagnosis is colonic ischemia (Option C). This form of ischemic bowel disease is the most common and usually results from a nonocclusive low-flow state in microvessels. The
term colonic ischemia is preferred to ischemic colitis because some patients do not have a documented inflammatory phase of disease. Risk factors for colonic ischemia include age (>60 years), female sex, vasoconstrictive and antihypertension medications, constipation, and thrombophilia.
Colonic ischemia presents with abrupt onset of lower abdominal discomfort that is mild to moderate and cramping, followed within 24 hours by hematochezia (passage of fresh blood or clots from the colon). Physical examination usually reveals lower abdominal tenderness over the involved colonic segment without peritoneal signs. Leukocyte count and blood urea nitrogen may be mildly elevated. Abdominal CT is indicated to assess the severity, phase, and distribution of colonic ischemia. CT findings are nonspecific, including segmental bowel wall thickening and pericolonic fat stranding, often in the distribution of the “watershed” areas of the colon (splenic flexure and rectosigmoid junction). Colonoscopy is the primary method to diagnose colonic ischemia, usually after CT has shown a thickened segment of colon.
Acute diverticulitis (Option A) often presents with colicky lower abdominal pain and left-lower- quadrant abdominal tenderness on physical examination. However, acute diverticulitis does not present with rectal bleeding, making this diagnosis unlikely. In addition, CT scans in acute diverticulitis typically show pericolonic fat stranding of the sigmoid colon with associated diverticulosis, which is not seen on this patient's CT scan.
Clostridioides difficile infection (Option B) can mimic the presentation of colonic ischemia and must be excluded by stool tests. However, bloody diarrhea is uncommon in C. difficile colitis, and the infection often involves the colon in a diffuse fashion rather than the segmental pattern seen on this patient's CT scan.
Ulcerative colitis (Option D) can present with abdominal pain and bloody stools. However, it usually involves the rectum and extends proximally in a continuous and symmetric pattern. This patient's CT scan, showing segmental thickening of the descending and sigmoid colon with sparing of the rectum, makes ulcerative colitis unlikely, as do the abrupt symptom onset and older patient age.
Key Point
Colonic ischemia is the most common form of ischemic bowel disease and usually results from a nonocclusive low-flow state in microvessels.
Colonic ischemia presents with abrupt-onset lower abdominal discomfort and cramping, followed within 24 hours by hematochezia.
Bibliography
Brandt LJ, Feuerstadt P, Longstreth GF, et al; American College of Gastroenterology. ACG clinical guideline: epidemiology, risk factors, patterns of presentation, diagnosis, and management of colon ischemia (CI). Am J Gastroenterol. 2015;110:18-44; quiz 45. PMID:
25559486 doi:10.1038/ajg.2014.395
Copyright 2019, American College of Physicians.
April 8, 2025
MKSAP 18 Gastroenterology & Hepatology, Question 19
A 60-year-old woman is evaluated 1 month after completing a 14-day course of Helicobacter pylori eradication therapy consisting of amoxicillin, clarithromycin, and omeprazole. Initial upper endoscopy before treatment showed patchy gastric erythema with no ulcers or erosions, and biopsies revealed H. pylori gastritis. Currently, she reports alleviated symptoms. She is otherwise healthy and takes no medication.
Which of the following is the most appropriate test to perform next?
A. Serologic antibody testing for H. pylori
B. Upper endoscopy with gastric biopsy
C. Urea breath test
D. No further testing
Responses Received from Members (813 Responses):
The Correct Answer is: C. Urea breath test
Educational Objective:
Evaluate for Helicobacter pylori eradication following treatment.
A urea breath test is the most appropriate next test for this patient. Testing to confirm eradication should be pursued in all cases of identified and treated Helicobacter pylori infection because of the established risks for peptic ulcer disease and gastric malignancy in patients with chronic H.pylori infection. To maximize the accuracy of testing to confirm eradication, testing should be performed a minimum of 4 weeks after completion of H. pylori eradication therapy and after proton pump inhibitor therapy has been discontinued for 1 to 2 weeks and H2-blockers for 1 to 2 days. The test chosen should be highly accurate in identifying active infection; appropriate tests include the urea breath test, fecal antigen test, or biopsy-based testing. The urea breath test is limited by need for specialized equipment and personnel and by its cost. The fecal antigen test is limited by the collection of stool but is less expensive than the urea breath test. Biopsy-based testing is expensive and invasive.
Unless upper endoscopy is indicated for other reasons, noninvasive testing modalities (the urea breath test or the fecal antigen test) are more appropriate for confirmation of eradication or assessment for reinfection. Both testing modalities are equivalent with regard to accuracy; therefore, the specific test chosen should be based on patient preference and/or test availability.
Serologic antibody testing is an inaccurate means of testing to confirm eradication because antibodies can remain present despite successful eradication of active infection; therefore, serologic testing cannot distinguish between past and current H. pylori infection.
Invasive (endoscopic) tests for H. pylori include the rapid urease test, histology, and culture; all invasive testing modalities identify active infection. Due to its expense and invasive nature, biopsy- based testing should be reserved for patients requiring a repeat upper endoscopy for other reasons (for example, follow-up endoscopy for high-risk gastric ulcer). In this patient with no indications for repeat upper endoscopy, one of the two noninvasive tests, either the urea breath test or fecal antigen test, is preferable.
Key Point
After eradication therapy for Helicobacter pylori infection, eradication should be confirmed using the urea breath test or fecal antigen test.
Bibliography
Lopes AI, Vale FF, Oleastro M. Helicobacter pylori infection—recent developments in diagnosis. World J Gastroenterol. 2014;20:9299-313. PMID: 25071324 doi:10.3748/wjg.v20.i28.9299
Copyright 2018, American College of Physicians.