## Diagnosis: Helicobacter pylori Chronic Gastritis ### Clinical & Histological Features **Key Point:** Chronic epigastric pain with early satiety and bloating in a 42-year-old, combined with histological chronic active gastritis and intestinal metaplasia, is classic for H. pylori–induced chronic gastritis. **High-Yield:** The **rapid urease test (RUT)** is positive — H. pylori produces urease, which cleaves urea to ammonia and CO₂, raising local pH and allowing bacterial survival in the acidic stomach. ### Resistance Patterns in India | Antibiotic | Resistance Rate in India | Clinical Impact | |---|---|---| | **Metronidazole** | >40% | High resistance; avoid in empiric regimens | | **Clarithromycin** | 20–30% | Moderate resistance; still used but declining efficacy | | **Amoxicillin** | <5% | Very low resistance; preferred | | **Tetracycline** | <5% | Very low resistance; used in quadruple therapy | **Clinical Pearl:** Metronidazole resistance in India is driven by prior use in anaerobic infections and giardiasis. Current Indian guidelines recommend **avoiding metronidazole** in first-line H. pylori eradication regimens. ### Recommended Regimens (India) 1. **Bismuth-based quadruple therapy** (preferred in high-resistance areas): - PPI (Omeprazole 20 mg BD) + Bismuth subsalicylate + Tetracycline + Metronidazole (10–14 days) - OR: PPI + Bismuth + Tetracycline + Clarithromycin 2. **Alternative triple therapy** (if bismuth unavailable): - PPI + Amoxicillin + Clarithromycin (10–14 days) - Success rate ~85–90% if clarithromycin-susceptible **Warning:** Do NOT use metronidazole as first-line due to high resistance. Amoxicillin should be retained because of its excellent susceptibility. ### Why Rapid Urease Test is Diagnostic - H. pylori produces urease constitutively - RUT turns colour within 15–60 minutes if H. pylori is present - Sensitivity ~95%, Specificity ~98% [cite:Park 26e Ch 19; Harrison 21e Ch 155]
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