A 34-year-old man comes to the office due to upper abdominal pain. The patient has vague discomfort that happens mostly in the afternoon and at night and is partially relieved by food. He sometimes feels nauseated. He has had no vomiting, black or bloody stools, or weight loss. The patient takes no prescription or over-the-counter medications. Family history is negative for cancer. Upper gastrointestinal endoscopy reveals a small ulcer with a clean base in the duodenal bulb. Biopsy of which of the following sites is most likely to demonstrate the infectious agent responsible for this patient's current condition?

Question

A 34-year-old man comes to the office due to upper abdominal pain.  The patient has vague discomfort that happens mostly in the afternoon and at night and is partially relieved by food.  He sometimes feels nauseated.  He has had no vomiting, black or bloody stools, or weight loss.  The patient takes no prescription or over-the-counter medications.  Family history is negative for cancer.  Upper gastrointestinal endoscopy reveals a small ulcer with a clean base in the duodenal bulb.  Biopsy of which of the following sites is most likely to demonstrate the infectious agent responsible for this patient's current condition?

Quizplus · Accepted Answer

11ec160b_395b_5188_9249_89847fb946dd_MD0001_00 Peptic (eg, duodenal, gastric, gastroesophageal) ulcers are most commonly due to Helicobacter pylori infection or use of nonsteroidal anti-inflammatory drugs. Because this patient takes no medications, his ulcer is likely due to H pylori infection. The site of ulcer formation is dependent on relative bacterial colonization density within the stomach. H pylori preferentially colonizes the gastric antrum, particularly early in the disease, although it may occur in other areas of the stomach or spread with time. Colonization of H pylori in the gastric antrum is associated with decreased somatostatin formation and increased gastrin secretion, which stimulate the parietal cells to produce excess acid. This results in an increased acid load emptying into the proximal duodenum, leading to duodenal ulcer (DU) formation. Biopsy of the antrum can confirm H pylori infection in patients with a DU, which characteristically presents with upper abdominal pain that improves with eating. In contrast, gastric ulcers (GUs) are associated with colonization in the gastric corpus (body). The etiology of GUs is not acid related, as these patients typically have normal or reduced acid levels, but is thought to be due to direct mucosal damage and chronic inflammation. Unlike DU pain, GU pain often worsens with eating. (Choices B and C) Patients with DUs who are infected with H pylori may test positive for the organism at multiple locations within the stomach. However, colonization density is highest within the antrum, not the gastric body or the gastric fundus; therefore, the antrum is the optimal site for biopsy. (Choices D and E) Although the ulcer occurs in the duodenum, high concentrations of H pylori are not typically found in the duodenal regions, as H pylori can colonize only gastric tissue or areas of gastric metaplasia. Educational objective: Helicobacter pylori is a common cause of peptic ulcers. Duodenal ulcers are associated with heavy colonization in the gastric antrum, whereas colonization in the gastric corpus is associated with gastric ulcers.

A 34-Year-Old Man Comes to the Office Due to Upper