Residency · Residency · Gastroenterology

Peptic Ulcer Disease and Helicobacter pylori

Epidemiology and Etiology

Changing Epidemiology

The epidemiologic landscape of peptic ulcer disease has undergone significant transformation over recent decades. The global prevalence of Helicobacter pylori is declining in developed nations, where it currently ranges from 30 to 40%, though it remains above 70% in developing countries. The overall incidence of peptic ulcer disease has declined due to the widespread use of proton pump inhibitors and successful H. pylori eradication campaigns. In developed countries, NSAID- and aspirin-related ulcers have now surpassed H. pylori as the most common etiology, although H. pylori remains the predominant cause on a global scale.

Etiologic Classification

Peptic ulcer disease is attributable to several distinct etiologies. H. pylori infection accounts for 60 to 70% of duodenal ulcers and 30 to 50% of gastric ulcers. NSAIDs and aspirin are responsible for 15 to 30% of cases, with risk being dose-dependent and mediated through COX-1 inhibition, which reduces prostaglandin-mediated mucosal protection. Idiopathic ulcers, defined as those that are both H. pylori-negative and NSAID-negative, constitute 10 to 20% of cases and represent an increasing proportion of peptic ulcer disease with notably worse clinical outcomes. Stress ulcers occur in the ICU setting and include Curling ulcers associated with severe burns and Cushing ulcers associated with central nervous system injury, the latter characterized by acid hypersecretion. Zollinger-Ellison syndrome, caused by a gastrinoma producing massive acid hypersecretion, accounts for less than 1% of peptic ulcer disease. Other rare causes include cytomegalovirus, herpes simplex virus, Crohn disease, crack cocaine use, bisphosphonates, radiation, and ischemia.

Helicobacter pylori

Microbiology and Virulence

Helicobacter pylori is a gram-negative, microaerophilic, spiral or helical rod equipped with flagella that enable motility within the gastric mucus layer. The organism produces urease, an enzyme that converts urea to ammonia and carbon dioxide, creating an alkaline microenvironment that protects the bacterium from gastric acid. This enzymatic activity forms the basis for several diagnostic tests, including the urea breath test, the rapid urease test, and the stool antigen test.

Among the virulence factors, CagA (cytotoxin-associated gene A) is of particular clinical significance. The CagA protein is injected into epithelial cells via a type IV secretion system, where it activates the SHP-2 oncogenic signaling pathway. CagA-positive strains are associated with an increased risk of peptic ulcer disease, gastric adenocarcinoma, and MALT lymphoma. VacA (vacuolating cytotoxin A) induces epithelial vacuolation and apoptosis, with the s1/m1 genotype being the most virulent. BabA and SabA are outer membrane adhesins that mediate epithelial attachment, while DupA is associated with an increased risk of duodenal ulceration.

Gastric Pathology Patterns

The pattern of gastritis produced by H. pylori infection has important implications for disease phenotype. Antral-predominant gastritis leads to increased acid secretion through loss of somatostatin-mediated negative feedback, predisposing to a duodenal ulcer phenotype. In contrast, corpus-predominant or pangastritis results in decreased acid secretion due to gland atrophy and destruction, predisposing to gastric ulcers, atrophic gastritis, intestinal metaplasia, and ultimately gastric cancer. The Correa cascade describes the sequential progression from H. pylori-associated chronic gastritis to chronic atrophic gastritis, intestinal metaplasia, dysplasia, and finally intestinal-type gastric adenocarcinoma.

Diagnostic Testing

Diagnostic testing for H. pylori is divided into non-invasive and invasive modalities. Among non-invasive tests, the urea breath test offers a sensitivity and specificity of approximately 95% each and is preferred for the test-and-treat strategy. The monoclonal stool antigen test achieves a sensitivity of 92 to 95% and specificity of 93 to 95%. Both tests require that proton pump inhibitors be held for at least 2 weeks and antibiotics or bismuth compounds for at least 4 weeks before testing to avoid false-negative results. Serology measuring IgG antibodies has a sensitivity of 85 to 95% but does not confirm active infection, as antibodies remain positive for years after eradication. Serology should only be used when urea breath testing or stool antigen testing is unavailable and the patient has not previously been treated.

Invasive tests performed during upper endoscopy include the rapid urease test (CLOtest), which has a sensitivity of 90 to 95% and requires 2 biopsies from the antrum and corpus. False negatives may occur in the setting of PPI use, recent antibiotics, or acute bleeding. Histology remains the gold standard, with the Sydney protocol recommending 5 biopsies (2 from the antrum, 2 from the corpus, and 1 from the incisura) with Giemsa or immunohistochemistry staining. Culture, while having lower sensitivity, allows for antibiotic susceptibility testing and is increasingly important given rising resistance rates. PCR-based molecular testing can simultaneously detect H. pylori and resistance mutations, including clarithromycin 23S rRNA and fluoroquinolone gyrA mutations, and is available as commercial assays.

<image>A diagnostic algorithm for H. pylori testing displayed as a flowchart. Start with "Suspected H. pylori infection" at top, branching to "EGD indicated?" Yes branch leads to invasive testing panel: rapid urease test (2 biopsies: antrum + corpus), histology (Sydney protocol: 5 biopsies), culture with susceptibility testing, and molecular/PCR testing. No branch leads to non-invasive testing: urea breath test (preferred) or monoclonal stool antigen test. Below both branches, show "Important pre-test requirements" box: PPI held >= 14 days, antibiotics/bismuth held >= 28 days, H2RA held >= 1-2 days. Arrow from positive result to "Treat" and from treatment to "Confirm eradication >= 4 weeks after completion of therapy (UBT or stool antigen preferred)" with note "Do NOT use serology for eradication confirmation." Use blue boxes for tests, green for positive management steps, and include sensitivity/specificity percentages for each test modality.</image>

Treatment — Current ACG/AGA Guidelines

First-Line Regimens (14 days preferred over 7-10 days)

Current guidelines recommend 14-day treatment courses over shorter durations for all first-line regimens. Bismuth quadruple therapy consists of a PPI twice daily, bismuth subsalicylate 524 mg four times daily, metronidazole 500 mg three to four times daily, and tetracycline 500 mg four times daily for 14 days. This regimen is the preferred first-line choice in areas of high clarithromycin resistance (exceeding 15%) or in patients with prior macrolide exposure. Concomitant therapy combines a PPI twice daily with amoxicillin 1 g twice daily, clarithromycin 500 mg twice daily, and metronidazole 500 mg twice daily for 14 days, and its advantage lies in its ability to overcome single-agent resistance. Clarithromycin triple therapy (PPI twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily for 14 days) should only be used when the local clarithromycin resistance rate is below 15% and the patient has no prior macrolide exposure; this regimen has been largely abandoned in North America. Rifabutin triple therapy (PPI twice daily, amoxicillin 1 g twice daily, and rifabutin 150 mg twice daily for 14 days), available as the FDA-approved combination product Talicia (omeprazole/amoxicillin/rifabutin), should be reserved for refractory cases due to the risk of myelotoxicity.

Penicillin-Allergic Patients

For patients with reported penicillin allergy, bismuth quadruple therapy using metronidazole and tetracycline is the recommended first-line regimen. However, it is important to note that more than 90% of reported penicillin allergies are not true allergies, and formal penicillin allergy testing should be considered to expand treatment options.

Susceptibility-Guided Therapy

Susceptibility-guided therapy is strongly recommended after the first treatment failure. Molecular testing for clarithromycin and levofloxacin resistance is preferred over traditional culture-based susceptibility testing. When susceptibility testing is unavailable following failure of first-line bismuth quadruple therapy, levofloxacin triple therapy (PPI, amoxicillin 1 g twice daily, and levofloxacin 500 mg daily for 14 days) or rifabutin triple therapy may be used.

Resistance Patterns

Understanding current resistance patterns is essential for rational antibiotic selection. Clarithromycin resistance ranges from 20 to 30% in North America and exceeds 40% in parts of Asia and Southern Europe. Metronidazole resistance is 20 to 40% globally but can be partially overcome by dose escalation and extended treatment duration. Levofloxacin resistance is 15 to 30% and increasing. Amoxicillin resistance remains below 2% globally, tetracycline resistance is below 5%, and rifabutin resistance is below 1%.

Confirmation of Eradication

Confirmation of H. pylori eradication is mandatory in all treated patients, as recommended by the ACG as a strong recommendation. Testing should be performed at least 4 weeks after completion of antibiotic therapy and at least 2 weeks after discontinuation of PPI therapy. The urea breath test or stool antigen test is preferred for eradication confirmation; serology should never be used for this purpose, as antibodies persist long after successful eradication. If eradication fails after two treatment courses, susceptibility-guided therapy becomes essential.

NSAID-Related Ulcer Disease

Risk Stratification

Risk stratification for NSAID-related ulcer disease is central to prevention strategies. High-risk patients are those with a prior complicated ulcer (bleeding or perforation) or multiple NSAID risk factors. Moderate-risk patients have 1 to 2 risk factors, which include age greater than 65, high-dose NSAID use, concurrent use of aspirin, corticosteroids, or anticoagulants, and a history of prior uncomplicated ulcer. Low-risk patients have no identifiable risk factors.

Prevention Strategies

Prevention strategies are tailored to the risk category. Low-risk patients may take NSAIDs without gastroprophylaxis. Moderate-risk patients should receive either a COX-2 selective inhibitor such as celecoxib or a traditional NSAID with concurrent PPI therapy. High-risk patients should avoid NSAIDs if possible; when NSAID use is unavoidable, a COX-2 selective inhibitor combined with a PPI provides the greatest protection.

Cardiovascular Considerations

The cardiovascular safety profile of NSAIDs requires careful consideration. COX-2 inhibitors carry an increased cardiovascular risk as demonstrated by the VIGOR and APPROVe trials, although the PRECISION trial showed that celecoxib at moderate doses carries cardiovascular risk equivalent to naproxen and ibuprofen. Among traditional NSAIDs, naproxen has the least cardiovascular risk due to its antiplatelet effect. Ibuprofen can interfere with aspirin's antiplatelet effect when taken concurrently, and patients on aspirin should be counseled to take aspirin at least 30 minutes before ibuprofen.

Peptic Ulcer Complications

Bleeding (most common complication)

Bleeding is the most common complication of peptic ulcer disease and is covered in detail in the Upper GI Bleeding lecture. The Forrest classification system is used to characterize endoscopic stigmata of hemorrhage and guide management decisions. H. pylori testing is mandatory in all patients presenting with a bleeding ulcer, with the important caveat that testing may yield false-negative results during acute bleeding, necessitating repeat testing in initially negative patients.

Perforation

Perforation occurs in 2 to 10% of patients with peptic ulcer disease and most commonly involves the anterior wall of the duodenal bulb. The diagnosis is suggested by the presence of pneumoperitoneum, which may be visualized as free air under the diaphragm on upright chest radiography or identified on CT imaging. Management requires emergent surgical repair, most commonly with a Graham patch omentoplasty, with a laparoscopic approach preferred when feasible. Post-operative management includes testing and treating for H. pylori, discontinuation of NSAIDs, and PPI therapy.

Gastric Outlet Obstruction

Gastric outlet obstruction results from chronic duodenal or pyloric channel ulceration leading to edema, fibrosis, and stenosis. Patients present with early satiety, nausea, vomiting, weight loss, and a succussion splash on physical examination. The diagnosis is established by upper endoscopy with biopsies to rule out malignancy, supplemented by an upper GI series. Management includes endoscopic balloon dilation to 15 to 18 mm in diameter, antisecretory therapy, and surgical intervention for refractory cases.

Penetration

Ulcer penetration occurs when an ulcer erodes into an adjacent organ, with the pancreas being the most common site for posterior duodenal ulcers. Patients typically report a change in their pain pattern with new radiation to the back, and lipase levels may be elevated. CT with contrast is the preferred diagnostic modality.

Gastric Ulcer Considerations

All gastric ulcers must be biopsied, with 4 to 6 biopsies obtained from the ulcer margin, to rule out underlying malignancy. A follow-up upper endoscopy should be performed in 8 to 12 weeks to document healing, and any unhealed ulcer should be rebiopsied. Giant gastric ulcers exceeding 3 cm in diameter carry a higher risk of malignancy and a higher rate of complications.

<image>An anatomical diagram of the stomach and duodenum showing common ulcer locations and their clinical significance. Show a labeled anterior view with the stomach (fundus, body, antrum, pylorus) and duodenal bulb. Mark four ulcer locations with colored circles: (1) Duodenal bulb anterior wall (red) - labeled "Most common site; perforation risk into peritoneum"; (2) Duodenal bulb posterior wall (blue) - labeled "Bleeding risk from gastroduodenal artery; penetration into pancreas"; (3) Gastric body lesser curvature (green) - labeled "Must biopsy to rule out malignancy; left gastric artery hemorrhage risk"; (4) Prepyloric/pyloric channel (yellow) - labeled "Gastric outlet obstruction risk." Include inset showing the relationship of the posterior duodenal ulcer to the gastroduodenal artery and pancreas. Label the relevant arterial supply: left gastric artery, right gastric artery, gastroduodenal artery, and pancreaticoduodenal arteries.</image>

Zollinger-Ellison Syndrome

Clinical Features

Zollinger-Ellison syndrome should be suspected in patients with multiple or refractory ulcers, particularly those in post-bulbar locations, as well as in patients with severe gastroesophageal reflux disease or diarrhea resulting from acid-mediated malabsorption and secretory mechanisms. Approximately 25% of gastrinomas are associated with multiple endocrine neoplasia type 1 (MEN1), a syndrome characterized by parathyroid hyperplasia, pituitary adenoma, and pancreatic neuroendocrine tumors.

Diagnosis

The diagnostic evaluation begins with measurement of fasting serum gastrin. A gastrin level exceeding 10 times the upper limit of normal with a gastric pH below 2 is virtually diagnostic. When gastrin is elevated between 2 and 10 times the upper limit of normal, a secretin stimulation test is performed by administering 2 IU/kg of secretin intravenously; a gastrin rise exceeding 120 pg/mL from baseline is considered positive. PPIs must be held for at least 7 days before gastrin measurement, with symptom control maintained using an H2 receptor antagonist or octreotide during this interval. Tumor localization is performed using CT or MRI, endoscopic ultrasound, and somatostatin receptor scintigraphy (Octreoscan) or, preferably, Ga-68 DOTATATE PET/CT.

Management

Acid control is achieved with high-dose PPI therapy, often requiring omeprazole at 60 to 120 mg per day in divided doses. Surgical resection of the gastrinoma is pursued when the tumor is localized and not associated with MEN1, with curative resection achievable in 30 to 40% of cases. In MEN1-associated gastrinomas, tumors are generally multifocal, and the role of surgery is controversial unless individual tumors exceed 2 cm in size.

Key Clinical Pearls

• Always test AND confirm eradication of H. pylori — do not assume treatment success
• PPI must be held >= 2 weeks before H. pylori testing (UBT, stool antigen, rapid urease test) to avoid false negatives
• Clarithromycin triple therapy should be abandoned in most of North America due to >20% resistance rates
• Bismuth quadruple therapy is the preferred empiric first-line regimen in regions with high clarithromycin resistance
• All gastric ulcers require biopsy and follow-up endoscopy to confirm healing and exclude malignancy
• NSAID + aspirin + anticoagulant = highest GI bleeding risk — minimize duration, add PPI, test/treat H. pylori
• Posterior duodenal ulcers bleed (gastroduodenal artery); anterior ulcers perforate
• Idiopathic ulcers (H. pylori-negative, NSAID-negative) are increasing in prevalence and have worse outcomes

References

1. Chey WD, et al. ACG Clinical Guideline: Treatment of Helicobacter pylori Infection. Am J Gastroenterol. 2017;112(2):212-239. (Update 2024 in press)
2. Fallone CA, et al. The Toronto Consensus for the Treatment of Helicobacter pylori Infection in Adults. Gastroenterology. 2016;151(1):51-69.
3. Laine L, et al. ACG Clinical Guideline: Upper Gastrointestinal and Ulcer Bleeding. Am J Gastroenterol. 2021;116(5):899-917.
4. Lanas A, Chan FKL. Peptic ulcer disease. Lancet. 2017;390(10094):613-624.
5. Shah SC, et al. AGA Clinical Practice Update on the Management of Refractory Helicobacter pylori Infection. Gastroenterology. 2021;160(5):1831-1841.

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