Helicobacter pylori and luminal gastric pH. Relationships in nonulcer dyspepsia

Effects of Helicobacter pylori gastritis on gastric secretion in healthy human beings

Helicobacter pylori gastritis is common, but effects on gastric secretion are not well understood. We measured basal and pentagastrin-stimulated gastric acidity, pepsin activity, and fluid output, as well as serum gastrin concentrations and H. pylori antibody levels, before and after treatment of H. pylori gastritis in 28 men and women. Subjects were studied before and 1 and 3 mo after a course of bismuth, metronidazole, and tetracycline. Elimination of H. pylori gastritis, accomplished in 14 subjects, increased basal and pentagastrin-stimulated gastric acidity (by 15 meq/l) and basal acid output significantly (by 2.1 meq/h 1 mo after therapy). Elimination of H. pylori had an opposite effect on pepsin secretion, significantly decreasing pepsin output by 30%. Elimination of H. pylori significantly reduced nonparietal fluid output by 35%, without affecting fluid output from parietal cells. Serum gastrin and H. pylori antibody levels declined significantly after elimination of H. pylori. None of these changes was observed in 14 subjects whose H. pylori gastritis was resistant to antimicrobial therapy. In summary, eradication of H. pylori infection increases gastric acidity by reducing nonparietal gastric secretion from peptic and other cells.

Clinical economics review: functional (non-ulcer) dyspepsia

Dyspepsia is common within the general population and it imposes a significant burden on health-care resources. Calculation of the economic implications of functional dyspepsia is constrained by the fact that it is only possible to make this diagnosis in a minority of individuals with the disorder, because many do not seek medical attention and investigation is not appropriate for all who do. Studies which attempt to assess the effectiveness or cost-effectiveness of therapy may be further constrained by the fact that there is now good evidence that many patients with dyspepsia seek medical attention not so much because of the severity of symptoms, but because they fear that the symptoms signal the presence of some serious underlying disease. In this situation, effective well-founded reassurance that no serious disease is present is an important outcome of medical intervention and one which should be included in an economic appraisal of dyspepsia management. For obvious reasons, it is sensible to compare the cost-effectiveness of various clinical management strategies applicable in dyspepsia. Decision-tree analyses are currently fashionable but suffer from the major defect that there is no theoretical basis from which patient satisfaction with treatment options can be assessed. It is suggested that for disorders such as functional dyspepsia, which are non-lethal and non-progressive, recommendations about acceptable clinical management strategies require that account be taken of patient satisfaction with the strategies being reviewed. Cost-effectiveness calculations which take no account of this aspect of outcome are of limited relevance to clinical practice.

What role does Helicobacter pylori play in dyspepsia and nonulcer dyspepsia? Arguments for and against H. pylori being associated with dyspeptic symptoms

A major role for Helicobacter pylori gastritis in nonulcer dyspepsia (NUD) is controversial. Gastroduodenal dysfunction may be associated with H. pylori infection, but there is little evidence for a causal link with dyspepsia. Population-based studies with appropriate methodology have generally failed to confirm an association between H. pylori and NUD. Furthermore, no definite association between subgroups of NUD (ulcer-like, dysmotility-like, reflux-like, and nonspecific) and H. pylori has been identified however the subgroups have been defined, and no specific symptom pattern characterizes patients with H. pylori infection. Whether H. pylori-induced alterations of gastric physiology can explain NUD remains open to debate while we await the results of more specific experiments. Although acid secretion in response to gastrin-releasing peptide may be increased in a subset of NUD patients who are infected with H. pylori, uninfected patients with NUD have not been assessed and the results require confirmation. Most studies suggest no association between H. pylori and gastroduodenal motor or sensory dysfunction in NUD. Treatment trials have been unconvincing. The trials with bismuth therapy have not been adequately blinded. Furthermore, some studies suggest that H. pylori-negative patients with NUD may respond to bismuth treatment, although the results have not been uniform. Therapies aimed at curing H. pylori infection have produced mixed results, with small positive and negative trials. The trials that have used adequate outcome measures have more often than not been negative. Based on current evidence, H. pylori is not established to be of causal importance in NUD.

Helicobacter pylori and non-ulcer dyspepsia

The role of Helicobacter pylori in non-ulcer dyspepsia continues to be controversial. While there is general agreement that incident infection with H. pylori can induce self-limited symptoms, the evidence linking the infection to chronic upper abdominal pain or discomfort in the absence of peptic ulceration is equivocal. The prevalence of H. pylori is at most only slightly increased in non-ulcer dyspepsia over the background population taking into account age, socioeconomic status and past ulcer history. However, it is yet to be convincingly shown that H. pylori precedes the onset of non-ulcer dyspepsia. It is now accepted that H. pylori is not associated with a specific symptom profile. Recent evidence suggests that a subgroup with H. pylori and non-ulcer dyspepsia have increased acid secretion in response to gastrin-releasing peptide, but gastric motor and sensory function appears not to be affected by the infection. The most persuasive evidence for a causal relationship between the infection and non-ulcer dyspepsia will come from ongoing large multicentre randomized placebo controlled trials, as the relatively small therapeutic trials to date have been unconvincing.

Review article: functional dyspepsia--should treatment be targeted on disturbed physiology?

In patients who present with chronic unexplained upper abdominal pain or discomfort (functional dyspepsia), therapy should ideally be targeted on correcting the individual's disturbed pathophysiology. Here, putative mechanisms implicated in functional dyspepsia and potential approaches to therapy are critically reviewed in order to determine if targeting treatment is of value. Pharmacological therapies reviewed include those that aim to correct disordered gastric emptying (e.g. cisapride, dopaminergic receptor antagonists, macrolides), reduce visceral hypersensitivity (e.g. somatostatin analogues, cholecystokinin antagonists, opioid agonists, serotonin type 3 receptor antagonists), reduce gastric acid secretion (e.g. H2-blockers, acid pump inhibitors), cure Helicobacter pylori infection, enhance muscosal defence (e.g. sucralfate, bismuth) or modify central nervous system processes. It is concluded that the imperfectly understood pathophysiology of functional dyspepsia contributes to the paucity of established efficacious therapies.