What is the appropriate diagnostic and treatment approach for a patient presenting with recurrent abdominal pain and a history of peptic ulcers suggestive of Helicobacter pylori (H. pylori) infection?

USMLE Step 3 CCS Case: H. pylori-Associated Peptic Ulcer Disease

Case Presentation

Initial Screen: A 42-year-old man presents to the outpatient clinic with a 3-month history of recurrent epigastric pain. The pain is gnawing in character, occurs 2-3 hours after meals, and occasionally wakes him at night. He reports partial relief with over-the-counter antacids. He denies weight loss, dysphagia, vomiting, or melena. No family history of gastric cancer. He takes ibuprofen occasionally for headaches but is not a regular NSAID user.

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Step 1: Initial Assessment and History (Outpatient Clinic - Time 0)

Orders to place immediately:

• Detailed history focusing on:

  • Duration and character of pain (epigastric, postprandial timing suggests peptic ulcer) 1
  • Alarm symptoms: weight loss, progressive dysphagia, recurrent vomiting, evidence of GI bleeding, family history of gastric cancer 1
  • NSAID/aspirin use (synergistically increases bleeding risk with H. pylori) 2
  • Previous ulcer history
  • Smoking status (increases peptic ulcer risk) 3

• Physical examination:

  • Vital signs
  • Abdominal examination (epigastric tenderness expected)
  • Check for pallor, lymphadenopathy, palpable masses 1

Key Decision Point: This patient is under 55 years old with NO alarm symptoms, so he does NOT require immediate endoscopy 1.

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Step 2: Diagnostic Testing Strategy (Outpatient Clinic - Time 0-15 minutes)

Critical medication review BEFORE ordering H. pylori testing:

• Ask specifically about PPI use - if patient is currently taking PPIs, they must be stopped for at least 2 weeks before testing to avoid false-negative results 1, 4
• If patient cannot stop PPIs: Order validated IgG serology instead (unaffected by PPIs) 4
• If patient is NOT on PPIs: Proceed with preferred non-invasive testing 1

Orders for H. pylori testing (choose ONE):

1. Urea breath test (13C-UBT) - PREFERRED first-line test 1
2. Stool antigen test - Alternative if UBT unavailable 1
3. Validated laboratory serology (only if above unavailable or patient cannot stop PPIs) - must have >90% sensitivity/specificity 1

DO NOT order:

• Whole blood rapid office tests (inadequate sensitivity/specificity) 1
• Endoscopy (not indicated in young patient without alarm symptoms) 1

Laboratory orders:

• Complete blood count (to assess for anemia from occult bleeding) 1
• Advance clock and await results

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Step 3: Results and Treatment Initiation (Outpatient Clinic - Day 3-5)

Scenario: H. pylori test returns POSITIVE

Immediate treatment orders (choose ONE regimen):

Option 1: Bismuth Quadruple Therapy (PREFERRED due to clarithromycin resistance) 2

• Bismuth subsalicylate 525 mg PO four times daily
• Metronidazole 250 mg PO four times daily
• Tetracycline 500 mg PO four times daily
• Omeprazole 20 mg PO twice daily
• Duration: 14 days 2

Option 2: Concomitant Therapy (Non-bismuth Quadruple Therapy) 2

• Omeprazole 20 mg PO twice daily 5
• Clarithromycin 500 mg PO twice daily
• Amoxicillin 1000 mg PO twice daily 6
• Metronidazole 500 mg PO twice daily
• Duration: 14 days 2

Option 3: Triple Therapy (if local clarithromycin resistance <15%) 6, 5

• Omeprazole 20 mg PO twice daily 5
• Clarithromycin 500 mg PO twice daily
• Amoxicillin 1000 mg PO twice daily 6
• Duration: 14 days 6, 5

Patient education orders:

• Take medications at start of meals to minimize GI intolerance 6
• Complete full 14-day course
• Avoid NSAIDs/aspirin during treatment 2
• Schedule follow-up in 6-8 weeks for test of cure

Advance clock to 6-8 weeks

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Step 4: Test of Cure (Outpatient Clinic - Week 6-8 Post-Treatment)

Critical timing requirement:

• Patient must be OFF all PPIs, antibiotics, and bismuth for at least 2 weeks before testing 1, 4
• If patient needs acid suppression: Switch to H2-receptor antagonist temporarily (does not affect bacterial load as severely) 1

Orders for confirmation of eradication:

• Urea breath test (13C-UBT) - PREFERRED 1
• OR Stool antigen test - Alternative 1

DO NOT use serology for test of cure (antibodies persist for months after eradication) 1

Advance clock and await results

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Step 5: Management Based on Test of Cure Results

Scenario A: Eradication SUCCESSFUL (Negative test)

Orders:

• Reassure patient
• Educate about 64% reduction in ulcer recurrence with successful eradication 7, 3
• Advise avoidance of NSAIDs; if needed, co-prescribe PPI 2
• No further H. pylori testing needed unless symptoms recur
• Discharge from care for this issue

Scenario B: Eradication FAILED (Positive test)

Critical consideration: Confirm result is not false-positive before retreating 1

Orders:

• If UBT was positive: Confirm with stool antigen test OR endoscopy before giving another course 1
• Once confirmed positive: Order second-line eradication therapy with DIFFERENT antibiotic regimen 2
• Consider endoscopy with culture and sensitivity testing to guide antibiotic selection 1
• Refer to gastroenterology if second treatment fails

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Step 6: Alternative Scenario - If H. pylori Test Initially NEGATIVE

Orders:

• Empirical PPI trial: Omeprazole 20 mg PO once daily for 4-6 weeks 1
• Reassess symptoms at 4 weeks
• If symptoms persist after PPI trial: Consider endoscopy to evaluate for H. pylori-negative ulcer (20% of ulcers), NSAID-induced ulcer, or other pathology 8, 7

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Key Pitfalls to Avoid in CCS

1. Ordering endoscopy in young patient without alarm symptoms - wastes time and resources 1
2. Testing for H. pylori while patient is on PPIs - produces false-negative in 10-40% of cases 4
3. Using serology for test of cure - antibodies persist regardless of eradication 1
4. Choosing triple therapy in areas with high clarithromycin resistance - leads to treatment failure 2
5. Testing for cure before 2 weeks off PPIs/antibiotics - false-negative result 1, 4
6. Not advancing clock appropriately - test of cure requires 6-8 weeks post-treatment
7. Ordering immediate endoscopy for age >55 - correct threshold is age >55 with NEW symptoms 1

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Critical Time Management for CCS

• Initial visit: 15 minutes (history, exam, order H. pylori test)
• Advance to Day 3-5: Review results, prescribe eradication therapy
• Advance to Week 6-8: Test of cure (after 2 weeks off all interfering medications)
• Final disposition: Based on eradication success

This stepwise approach prioritizes mortality reduction through gastric cancer prevention (H. pylori eradication halts progression to atrophic gastritis and reduces cancer risk) 1 and morbidity reduction through ulcer recurrence prevention (eradication reduces duodenal ulcer recurrence to nearly 0% and gastric ulcer recurrence by 69%) 7, 3.