Gastroenterology · Peptic Ulcer Disease
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Helicobacter pylori is the most common cause of duodenal ulcers and is strongly associated with gastric adenocarcinoma and MALT lymphoma.
The urea breath test and stool antigen test are the preferred non-invasive diagnostic modalities for active infection.
Patients must discontinue proton pump inhibitors (PPIs) for two weeks and bismuth/antibiotics for four weeks prior to testing to avoid false-negative results.
Endoscopic biopsy is the preferred diagnostic route in patients already undergoing EGD for alarm symptoms; both rapid urease testing and histology are used, and recent PPI, bismuth, or antibiotic exposure reduces the sensitivity of either.
First-line treatment is quadruple therapy consisting of a PPI, bismuth subsalicylate, metronidazole, and tetracycline for 14 days.
PPI-clarithromycin triple therapy is no longer a first-line option because of resistance; clarithromycin regimens should be avoided unless susceptibility is demonstrated, though PCAB (vonoprazan)-clarithromycin triple therapy remains a conditionally suggested first-line alternative.
Confirmation of eradication via repeat urea breath test or stool antigen test is required at least four weeks after completing therapy.
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A 45-year-old male presents with a three-month history of epigastric pain that improves with meals but worsens 2-3 hours later. He reports occasional melena and has lost 5 pounds due to fear of eating. He has been taking omeprazole daily for the past month to manage his symptoms. Physical examination reveals mild epigastric tenderness without guarding or rebound. An endoscopy is performed, revealing a 1 cm duodenal ulcer.
Which diagnostic test is most appropriate to confirm the presence of H. pylori in this patient?
Rapid urease test (CLO test) via endoscopic biopsy
Because the patient is already undergoing endoscopy for alarm symptoms (weight loss, melena), endoscopic biopsy is the most efficient route to diagnosis. Note that PPIs reduce the sensitivity of biopsy-based tests as well, so gastric histology (which is less affected than the rapid urease test) should accompany the urease test in a patient taking omeprazole.
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Etiology / Epidemiology
Gram-negative, spiral-shaped rod transmitted via fecal-oral or oral-oral routes. Primary risk factor is low socioeconomic status and crowded living conditions.
Clinical Manifestations
Often asymptomatic; presents as dyspepsia, epigastric pain, or peptic ulcer disease. Hematemesis or melena suggests active ulceration.
Diagnosis
Urea breath test or stool antigen test are the non-invasive gold standards. Must hold PPIs for 2 weeks prior to testing.
Treatment
First-line is quadruple therapy: Bismuth subsalicylate, Metronidazole, Tetracycline, and a PPI for 14 days.
Prognosis
Strong association with gastric adenocarcinoma and MALT lymphoma. Eradication reduces risk of recurrent ulcers.
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Epidemiology & Etiology
Infection is highly prevalent globally, often acquired in childhood. Transmission is facilitated by poor sanitation and close contact. It is the leading cause of chronic gastritis worldwide.
Pertinent Anatomy
Colonizes the gastric antrum primarily, where it survives the acidic environment. It utilizes urease to create a protective alkaline microenvironment, allowing survival beneath the gastric mucus layer.
Pathophysiology
The organism produces urease, which converts urea to ammonia, neutralizing gastric acid. This leads to mucosal inflammation, epithelial cell damage, and increased gastrin release. Chronic inflammation results in atrophic gastritis and loss of somatostatin-producing D-cells.
Clinical Manifestations
Patients typically report gnawing epigastric pain that may improve or worsen with food. Red flag symptoms include unintentional weight loss, dysphagia, and iron deficiency anemia. Chronic infection is the primary driver of peptic ulcer disease.
Diagnosis
The urea breath test and fecal antigen test are both highly accurate non-invasive tests for active infection. Endoscopy with biopsy is reserved for patients with alarm symptoms or new-onset dyspepsia at age >60 (some guidelines use a ≥55-60 threshold). False negatives occur if the patient has taken PPIs or antibiotics within 2-4 weeks of testing.
Treatment
Standard quadruple therapy is required due to rising resistance. Patients on metronidazole should avoid alcohol during therapy and for at least 3 days afterward because of a labeled disulfiram-like reaction. Tetracycline is teratogenic and contraindicated in children and pregnancy.
Prognosis
Successful eradication is confirmed via urea breath test or stool antigen 4 weeks post-treatment. Failure to treat increases the risk of gastric adenocarcinoma and MALT lymphoma. Long-term monitoring is required for patients with pre-malignant changes.
Differential Diagnosis
NSAID-induced gastritis: history of chronic analgesic use
Zollinger-Ellison syndrome: refractory ulcers with high gastrin levels
Gastric cancer: weight loss and early satiety
GERD: retrosternal burning rather than epigastric pain
Functional dyspepsia: diagnosis of exclusion with normal endoscopy