Helicobacter pylori

1. GC 092 slide: Diagnosis of H. pylori — invasive (CLO test, culture for sensitivity, histology with special stains) and non-invasive (serology = antibody; UBT = urease activity; stool = antigen). UBT and stool antigen are marked as "useful for monitoring after treatment" while serology is NOT. ^[1] This is the single highest-yield slide for diagnosis questions.

2. Teaching clinic learning point: PPIs and antibiotics must be discontinued 2–4 weeks before UBT and CLO test to avoid false negatives. Serology remains useful when patients cannot stop these medications but cannot differentiate active from past infection. ^[8] This is a classic MCQ discriminator.

3. Teaching clinic learning point: In areas with high clarithromycin resistance, bismuth quadruple therapy (PPI + bismuth + tetracycline + metronidazole) is preferred. 14-day regimens now recommended over shorter courses. Sensitivity testing should be considered after treatment failure. ^[8]

4. Senior notes (GC block): CLO test gives false negative for TWO reasons — (1) recent PPI/antibiotics suppress bacterial load below diagnostic threshold; (2) blood interferes with test results (e.g. bleeding ulcer). ^[2]

5. Senior notes: H. pylori → chronic atrophic gastritis → intestinal metaplasia → body/distal gastric adenocarcinoma (intestinal type, Lauren classification). ^[6] This carcinogenesis cascade is a frequent SAQ/MCQ target.

6. Uninvestigated dyspepsia algorithm (GC lecture): Age ≥ 60 or red flags → endoscopy first; Age < 60 without red flags → test-and-treat H. pylori; if H. pylori −ve or no response → empiric antisecretory therapy. ^[7]

• UBT vs Serology for eradication confirmation: UBT (or stool antigen) is the correct answer for post-treatment testing. Serology is the classic wrong answer — antibodies persist for months.
• CLO test false negative in bleeding patients: If the stem describes an actively bleeding ulcer, CLO test sensitivity drops — examiners test whether you know to biopsy from body as well or repeat testing later.
• H. pylori vs Zollinger-Ellison: Recurrent/refractory ulcers at atypical locations (distal duodenum/jejunum) + H. pylori −ve + no NSAIDs → think gastrinoma, not treatment-resistant H. pylori.
• NSAIDs vs H. pylori as PUD cause: When asked for "most common cause of PUD apart from H. pylori," the answer is NSAIDs (including aspirin) ^[5][9].
• Functional dyspepsia coexistence: Finding H. pylori in a patient with functional dyspepsia does NOT change the FD diagnosis — they can coexist. Eradicate H. pylori anyway as it may help symptoms ^[7].

2022 Fourth Summative Minicase, Case 1, Section 1 Q1 ^[5]:

"A 65-year-old man was admitted for fresh haematemesis. He volunteered a history of Helicobacter pylori infection with triple therapy given 10 years ago. He had no known drug allergy. … What are the components of triple therapy (if no known penicillin allergy) and the optimal duration of the regimen? (8 marks)"

• Answer: PPI + amoxicillin + clarithromycin for 14 days. Key: if penicillin allergy, substitute amoxicillin with metronidazole.

2022 Fourth Summative Minicase, Case 1, Section 4 Q11 ^[9]:

"Name the MOST COMMON cause of peptic ulcer disease apart from Helicobacter pylori infection. (3 marks)"

• Answer: NSAIDs (including aspirin).

2022 Fourth Summative Minicase, Case 1, Section 4 Q10 ^[9]:

"What is Forrest class IIa ulcer? (2 marks)"

• Answer: Non-bleeding visible vessel (ulcer with a visible vessel without active bleeding). High rebleeding risk; requires endoscopic intervention.

2025 Fourth Summative SAQ Q10 ^[10]:

"A 62-year-old man without known drug allergy was admitted for fresh melena. He had a history of failed Helicobacter pylori eradication by clarithromycin-based triple therapy. … (a) What is the sign to look for on chest X-ray? (2 marks) (b) What is Forrest IIa ulcer? (2 marks) (c) Name two methods for endoscopic haemostasis of Forrest IIa ulcer? (4 marks) (d) Name the combination of drugs of bismuth quadruple therapy to eradicate Helicobacter pylori infection. (2 marks)"

• Answers: (a) Free gas under diaphragm (pneumoperitoneum) — to exclude perforation. (b) Non-bleeding visible vessel. (c) Adrenaline injection + thermal coagulation / haemoclip application / any two of: injection, thermal, mechanical methods. (d) PPI + bismuth subsalicylate + tetracycline + metronidazole — this is the rescue regimen after clarithromycin triple therapy failure.

2021 Fourth Summative MCQ Q71 ^[11]:

"A 55-year-old gentleman presented with a 4 cm ulcer in the posterior gastric antrum. … After 6 months of medical therapy, including a proton pump inhibitor, he continued to complain of intermittent epigastric pain. … Repeated endoscopy and biopsies showed that the ulcer was of the same size and was benign on histologic examination. What is the MOST APPROPRIATE management at this stage?"

• Answer: A. Distal gastrectomy. Rationale: refractory benign gastric ulcer despite 6 months of adequate medical therapy (including PPI) with ongoing symptoms and anaemia — surgical resection is indicated for non-healing gastric ulcers due to malignancy risk and complications.