172.1 🎓 醫孞生版

172.1.0.1 📌 䞀頁重點

  • 菌: Helicobacter pylori — Gram - curved/spiral rod, urease + (very strong), oxidase +, microaerophilic, motile (multiple polar flagella)
  • Habitat: 胃黏膜 mucus å±€, urease 將 urea → NH3 äž­å’Œ stomach acid → 掻
  • 流行病孞: ~ 50%+ 党球; 高所埗 declining, low-income still high
  • Diseases:
    • Asymptomatic colonization (倧倚)
    • Chronic gastritis (universal in carriers)
    • Peptic ulcer disease (PUD) — duodenal (90% link H. pylori) and gastric ulcer (80%)
    • Gastric adenocarcinoma (Class I carcinogen per IARC)
    • MALT lymphoma (eradication can cure early stage)
    • ITP — eradication helps some
    • Iron deficiency anemia — refractory cases
  • Diagnosis:
    • Non-invasive: urea breath test (UBT), stool antigen (high sens/spec); serology limited (not differentiate active vs past)
    • Invasive (EGD biopsy): rapid urease test (CLO), histology, culture (for AST)
    • Hold PPI ≥ 2 wk before UBT/stool (PPI ↓ urease activity → false neg)
  • Treatment (2024 ACG / Maastricht VI):
    • First-line: Bismuth quadruple (PPI + bismuth + tetracycline + metronidazole) × 14d → 90%+ cure
    • OR Concomitant quadruple (PPI + amox + clari + metro × 14d) — 若 clarithromycin R < 15%
    • OR PCAB-based (vonoprazan + amox + clari, or P-CAB + amox dual)
    • Clarithromycin triple 䞍再 preferred (R 高 globally)
  • Test of cure: UBT or stool antigen ≥ 4 wk after; off PPI ≥ 2 wk

172.1.0.2 1⃣ 现菌孞 + 臎病

  • Spiral / curved gram - rod
  • Urease極匷 — converts urea → NH3 + CO2 → buffer acid 呚圍 → 存掻 stomach
  • Motile (flagella) — 進 mucus å±€ (近 epithelium, pH ~ 7)
  • Adheres to gastric epithelium via BabA (Lewis b binding)
  • Virulence factors:
    • CagA (cytotoxin-associated gene A) — type IV secretion → inflammation, carcinogenesis
    • VacA (vacuolating cytotoxin) — induces vacuole + apoptosis
    • OipA, BabA adhesins
    • CagA + + VacA s1m1 = highest disease risk strain
172.1.0.2.1 Pathogenesis
  • 慢性 inflammation → atrophic gastritis → intestinal metaplasia → dysplasia → adenocarcinoma
  • Duodenal ulcer pathway: 倚 antrum colonization → 增 gastrin → 增 acid → duodenal damage
  • Gastric ulcer: 倚 corpus colonization → atrophic gastritis → æž› acid → epithelial damage

172.1.0.3 2⃣ 臚床衚珟

172.1.0.3.1 A. Asymptomatic (倧倚)
  • 倚敞 carriers no obvious sx
  • 仍 chronic gastritis histology
172.1.0.3.2 B. Peptic Ulcer Disease
  • Duodenal ulcer: 痛 epigastric, hunger/night pain, relief with food, H. pylori 90%+ when 䞍 NSAID
  • Gastric ulcer: 痛 worse with food, weight loss, H. pylori ~ 80%
  • Complications: bleed, perforation, obstruction
172.1.0.3.3 C. Gastric Adenocarcinoma
  • Class I carcinogen (IARC)
  • Distal (non-cardia) adenocarcinoma mostly
  • Long latency (decades)
  • Endemic regions: Japan, Korea, China, Taiwan
  • Eradication 降 incidence by ~ 50% in trials
172.1.0.3.4 D. MALT Lymphoma
  • Gastric MALT (mucosa-associated lymphoid tissue) lymphoma
  • ~ 90% H. pylori-driven
  • Early-stage (stage IE) eradication → 70-80% complete regression
  • Advanced + t(11;18) → eradication less effective; chemotherapy
172.1.0.3.5 E. Functional Dyspepsia
  • Test-and-treat strategy in non-investigated dyspepsia (< 60 yo, no red flags)
  • ~ 5-10% benefit from eradication
172.1.0.3.6 F. Extraintestinal
  • ITP — eradication helps some refractory adults
  • Iron deficiency anemia — refractory, eradication helps
  • Vitamin B12 deficiency — possible

172.1.0.4 3⃣ 蚺斷

172.1.0.4.1 Non-invasive Tests
Test Sensitivity Specificity Notes
Urea breath test (UBT) 95%+ 95%+ First-line; hold PPI 2 wk
Stool antigen (monoclonal) 95%+ 95%+ Equivalent to UBT; hold PPI 2 wk
Serology 85-90% 85% Past vs active 䞍分; older test 挞 retire
Salivary Variable Research / public health
172.1.0.4.2 Invasive (EGD Biopsy)
Test Notes
Rapid urease test (CLO test) Quick, antrum + corpus biopsy; PPI false neg
Histology (Giemsa, IHC) Gold standard; also see gastritis severity, dysplasia
Culture Slow, but allows AST (susceptibility testing) for refractory cases
PCR Detect organism + R mutations
172.1.0.4.3 䜕時 test (Indications — ACG 2017 + Maastricht VI 2022)
  • Active or past PUD
  • Gastric MALT lymphoma
  • Early gastric CA after resection
  • 䞍查 dyspepsia < 60 yo + no alarm features → test-and-treat
  • 䞍查 GERD-only (not increased H. pylori risk)
  • 䞍查 NSAID users routinely (controversial; testing if high-risk for ulcer)

172.1.0.5 4⃣ 治療 (2024 Updates)

172.1.0.5.1 First-Line Choices
172.1.0.5.2 A. Bismuth Quadruple × 14d (BQT)
  • PPI bid + Bismuth subsalicylate 524 mg qid + Tetracycline 500 mg qid + Metronidazole 250-500 mg qid
  • 90%+ cure rate
  • Best for areas with clarithromycin R > 15% (most of globe)
  • 副䜜甚: nausea, dark stool, metallic taste
172.1.0.5.3 B. Concomitant Quadruple × 14d (CQT)
  • PPI + Amoxicillin 1 g bid + Clarithromycin 500 bid + Metronidazole 500 bid
  • 90%+ cure if clari R < 15%
  • 4 drugs daily for 14d — adherence issue
172.1.0.5.4 C. Vonoprazan-based (PCAB) Triple/Dual
  • Vonoprazan 20 mg bid + Amox 1 g tid ± Clarithromycin 500 bid × 14d
  • FDA 2022 (Voquezna Triple); PCAB more potent acid suppression
  • Cure ~ 85% (triple), ~ 80% (dual without clari) in resistant strains
  • No clari needed in dual — alternative for high R area
172.1.0.5.5 Not Preferred (Due Rising Resistance)
  • Clarithromycin triple (PPI + amox + clari × 7-14d) — cure 70% only when R > 15%
  • Sequential 10d (PPI + amox 5d → PPI + clari + metro 5d)
172.1.0.5.6 Second-Line (Failed First-Line)
  • If had clari → bismuth quadruple
  • If had bismuth quadruple → levofloxacin triple (levo + amox + PPI × 10-14d)
  • Rifabutin triple (rare; rifabutin + amox + PPI) — third-line
172.1.0.5.7 Allergy
  • PCN allergy → bismuth quadruple (no amox)
  • Tetracycline avoided 兒童 < 8 yr + pregnancy
172.1.0.5.8 Test of Cure
  • ≥ 4 wk after treatment, off PPI ≥ 2 wk
  • UBT or stool antigen
  • Refractory → culture + AST 蚭蚈 individual regimen

172.1.0.6 5⃣ Prevention + Future

  • 衛生 + 食氎
  • Vaccine in development (multiple candidates, Phase 2 — challenges with mucosal immunity)
  • Mass screening + treatment in high-CA-incidence countries (Japan, Korea Taiwan ongoing)
  • Family screening if proband + gastric CA (1st-degree)