The Cause of gastritis and peptic ulcer disease

THIS YEAR’S Nobel Laureates in Physiology or Medicine challenged prevailing dogmas and made the remarkable and unexpected discovery that inflammation in the stomach (gastritis) as well as ulceration of the stomach or duodenum (peptic ulcer disease) are the result of an infection of the stomach caused by the bacterium Helicobacter pylori.


When conventional belief was challenged

Stress and lifestyle were considered the major causes of peptic ulcer disease until the discovery by the Nobel Laureates

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– Signs of inflammation were always present in the gastric mucosa close to the bacteria
– Helicobacter pylori causes more than 90 per cent of duodenal ulcers and up to 80 per cent of gastric ulcers
– Inflammation predisposes not only to ulcer in the corpus region, but also to stomach cancer
– Antibiotics cure but can lead to resistance

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THIS YEAR’S Nobel Laureates in Physiology or Medicine challenged prevailing dogmas and made the remarkable and unexpected discovery that inflammation in the stomach (gastritis) as well as ulceration of the stomach or duodenum (peptic ulcer disease) are the result of an infection of the stomach caused by the bacterium Helicobacter pylori.

In 1982, when this bacterium was discovered by Barry J. Marshall (born 1951) who now runs a laboratory at the University of Western Australia and J. Robin Warren (born 1937), a pathologist from Perth, Australia, stress and lifestyle were considered the major causes of peptic ulcer disease.

Crucial observation

But things changed when Warren observed small curved bacteria colonising the lower part of the stomach (antrum) in about 50 per cent of patients from whom biopsies had been taken.

He made the crucial observation that signs of inflammation were always present in the gastric mucosa close to where the bacteria were seen.

The duo initiated a study of biopsies from 100 patients to conclusively prove that the bacterium was indeed the culprit. The first success came when Marshall succeeded in cultivating a hitherto unknown bacterial species (later denoted Helicobacter pylori) from several of these biopsies.

The crucial observation that the organism was present in almost all patients with gastric inflammation, duodenal ulcer or gastric ulcer helped them propose that Helicobacter pylori was involved in the aetiology of these diseases. It is now firmly established that Helicobacter pylori causes more than 90 per cent of duodenal ulcers and up to 80 per cent of gastric ulcers. Another confirmation that it is indeed the bacterium that caused inflammation and peptic ulcer, came from the way ulcers frequently relapsed after being healed by inhibiting gastric acid production.

The reason was simple; relapse was inevitable in most cases, as the bacteria and the resultant chronic inflammation of the stomach remained and the bacteria were not eradicated.

The link between Helicobacter pylori infection and subsequent gastritis and peptic ulcer disease has been established through studies of human volunteers, antibiotic treatment studies and epidemiological studies.

In treatment studies, Marshall and Warren as well as others showed that patients could be cured from their peptic ulcer disease only when the bacteria were eradicated from the stomach.

Thanks to the pioneering discovery by Marshall and Warren, peptic ulcer disease is no longer a chronic, frequently disabling condition, but a disease that can be cured by a short regimen of antibiotics and acid secretion inhibitors.

Life-long infection

Helicobacter pylori is a spiral-shaped Gram-negative bacterium that colonises the stomach in about 50 per cent of all humans. In developing countries virtually everyone may be infected.

Infection is typically contracted in early childhood, frequently by transmission from mother to child, and the bacteria may remain in the stomach for the rest of the person’s life.

The severity of this inflammation and its location in the stomach is of crucial importance for the diseases that can result from Helicobacter pylori infection. In most individuals Helicobacter pylori infection is asymptomatic.

However, about 10-15 per cent of infected individuals will sometimes experience peptic ulcer disease. Such ulcers are more common in the duodenum than in the stomach itself.

Associated malignancies

In some individuals Helicobacter pylori also infects the corpus region of the stomach. This results in a more widespread inflammation that predisposes not only to ulcer in the corpus region, but also to stomach cancer.

This cancer has decreased in incidence in many countries during the last half-century but still ranks as number two in the world in terms of cancer deaths.

The bacterium itself is extremely variable, and strains differ markedly in many aspects. Even in a single infected individual all bacteria are not identical, and during the course of chronic infection bacteria adapt to the changing conditions in the stomach with time.

Drug resistance

Likewise, genetic variations among humans may affect their susceptibility to Helicobacter pylori. Antibiotics treatment can get rid of the bacteria.

But an indiscriminate use of antibiotics to eradicate the bacteria from healthy carriers would lead to drug resistance.

Therefore, treatment against Helicobacter pylori should be used restrictively in patients without documented gastric or duodenal ulcer disease. — Our Bureau

Courtesy: The Hindu

One Response

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