Colonisation of the stomach with Helicobacter pylori is seen in virtually all patients with duodenal ulcer and 70-80% of those with gastric ulcers;2 this close association is not seen in ulcers complicating NSAID therapy. In patients with duodenal ulcer there is an associated antral gastritis whereas with gastric ulcer, gastritis is more diffuse throughout the stomach. It is not known how Helicobacter pylori predisposes to peptic ulceration, but chronic infection with the organism, which establishes itself within and below the mucus layer, is associated with hypergastrinaemia and hyperacidity. The hypergastrinaemia may result from reduced antral production of somatostatin, which inhibits gastrin formation. Production of ammonia by urease by Helicobacter pylori may also play a role. With more extensive gastritis there is a reduction in parietal cell mass and decreased acid secretion. Although all patients colonised with Helicobacter pylori develop gastritis, only about 20% have ulcers or other lesions, and host factors are likely to be important.
Other possible effects of long-term infection with Helicobacter pylori include gastric carcinoma and lymphoma, particularly of the MALT (Mucosa Associated Lymphoid Tissue) type. Eradication of the organism may lead to resolution of the latter tumour.
Helicobacter pylori can be detected histologically from antral biopsies obtained at gastroscopy, or biochemically. In the CLO test an endoscopic biopsy specimen is incubated in a medium containing urea and an indicator which chages colour if ammonia is produced. Proton pump inhibitors and bismuth compounds suppress but do not eradicate Helicobacter pylori, and results may be falsely negative if any of these tests is carried out within a month of taking these drugs.
1 Gonzales C H et al 1998 Lancet 351:1624-1627.
2 First reported by B Marshall and R Warren (Lancet 19831: 1273 and 1273-1274). The association was initially greeted with widespread disbelief and sometimes hostility. Warren reports: "I was just doing my day-to-day pathology. I like looking for funny things and this day, I saw a funny thing and started wondering." In a gastric biopsy he saw "numerous bacteria in close contact with the surface epithelium ... They appeared to be actively growing and not a contaminant." The story of Helicobacter pylori had begun. (Lancet 2001 345: 694.)
Was this article helpful?
Do You Suffer From High Blood Pressure? Do You Feel Like This Silent Killer Might Be Stalking You? Have you been diagnosed or pre-hypertension and hypertension? Then JOIN THE CROWD Nearly 1 in 3 adults in the United States suffer from High Blood Pressure and only 1 in 3 adults are actually aware that they have it.