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Helicobacter%20pylori%20infection Diagnosis
Evaluation
- Thorough history and physical exam should be done to rule out other causes for dyspeptic symptoms [eg cardiac, hepatobiliary, medication induced eg nonsteroidal anti-inflammatory drugs (NSAIDs), dietary indiscretion, lifestyle, etc]
- Patients with dominant symptoms of heartburn or acid regurgitation without a history of peptic ulcer disease (PUD) need not be tested for H pylori infection but should be treated for gastroesophageal reflux disease (GERD)
- Please see Gastroesophageal Reflux Disease disease management chart for further information
- In H pylori-infected patients, the risk of ulcer disease is increased with NSAID and aspirin use
- Eradication of H pylori in patients on long-term NSAID use does not enhance the healing of gastric or duodenal ulcers and these patients should be treated appropriately for NSAID-induced ulcer
- Please see Peptic Ulcer Disease disease management chart for further information
Assessment
Patients with alarm symptoms require prompt endoscopic investigation
- Unexplained weight loss or anorexia
- Recurrent vomiting
- >50 years old (cut-off age will depend on national cancer incidence rates)
- Evidence of gastrointestinal bleeding, iron-deficiency anemia, idiopathic thrombocytopenic purpura, vitamin B12 deficiency, or positive occult blood test
- Dysphagia or odynophagia
- Failure of multiple treatments
- Jaundice
- Presence of abdominal mass
Screening
“Test and Treat” for Helicobacter pylori in Primary Care
- Routine testing is not recommended, performed only in patients who will require therapy if results are positive
- Two positive tests are required for H pylori diagnosis
- Urea breath test (UBT) and stool antigen test are the preferred methods of diagnosis in the primary care setting
- If UBT and stool antigen test are not available, serological test (mainly IgG) is a satisfactory alternative
- A delayed test (either a UBT or histology) should be done within 4-8 weeks of an acute upper gastrointestinal bleed following a negative endoscopy
- In cases where an endoscopy is indicated and biopsy is not contraindicated, a rapid urease test is recommended as primary diagnostic test
- Pepsinogen serology may be considered in patients with antrum-restricted atrophy to evaluate the status of the gastric mucosa & as a marker for atrophic gastritis
| METHODS OF H PYLORI TESTING | ||
| MODALITY | ADVANTAGES | DISADVANTAGES |
| Noninvasive | ||
| Urea breath test (UBT) | Highly specific & sensitive Reliable, inexpensive, rapid, quantitative Gold standard test for asymptomatic patients Most valuable for assessing response to therapy after 4-8 weeks Useful for eradication confirmation Allows detection of bleeding |
Rarely w/ false-positive results due to urease-positive organisms Provides no information about antibiotic resistance |
| Stool antigen test | Highly specific & sensitive Rapid, simple & can be modified Enzyme-linked immunosorbent assay (ELISA) is the most accurate |
Requires withholding of some medications prior to testing |
| Serology | Rapid, quantitative, inexpensive Recommended for initial screening Not affected by gastric bleeding |
Low sensitivity specificity Not for eradication confirmation Does not distinguish between active & past infection |
| Invasive | ||
| Endoscopy with biopsy and rapid urease test (RUT) | Endoscopy: Permits inspection of pathology Allows detection of ulcers, neoplasm RUT: Highly sensitive and specific Rapid Inexpensive Most handful test in a clinical setting |
Endoscopy: Invasive, expensive Unable to visualize H pylori RUT: Requires withholding of some medications prior to testing |
| Culture | Highly specific Permits determination of antimicrobial susceptibility |
Low sensitivity Expensive Time-consuming Expert personnel & care during transport required PPI and antibiotic use increase chances of false-negative result |
| Histology | Highly specific, simple and inexpensive More sensitive than culture Allows direct visualization of organism extent |
Several days for result Nature of tissue involvement With high rate of false-negative results |
| Polymerase chain reaction (PCR) | Very good specificity sensitivity - Liquid phase (DNA-enzyme immunoassay) and reverse dot blot probe assay (LiPA) increase PCR's specificity and sensitivity Rapid and accurate results Permits determination of antimicrobial susceptibility and virulence typing |
Expensive Expert personnel and longer time to process required Not widely available |
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