H Pylori Infection and Stomach Ulcer
The stomach ulcers, or peptic ulcers, can be defined as a painful disruption of the stomach lining. This lesion occurs when the thick external layer of the mucous membrane of the stomach is reduced by different harmful agents, so the pepsin and digestive acids can reach the underlaying tissues of the stomach and proximal intestine (duodenum), thus destroying them.
Any external factor able to cause an imbalance between the protective mechanisms of the stomach mucous membrane and the digestive acids can produce an injury which eventually will grow up into an ulcer.
However, the most common cause of stomach ulcers is H. pylori bacteria, which has different properties that allow it to damage the membrane lining the stomach and colonize it. Therefore, many authors refer to H. pylori peptic ulcer as "endemic ulcer".
However, there are other factors that can increase the stomach mucous membrane damage, for example, taking NSAIDs (nonsteroidal anti-inflammatory drugs like ibuprofen and aspirin) constantly during a long time, stomach hyperacidity (like in Zollinger-Ellison syndrome), a lifestyle with a lot of stress, smoking, alcoholism, eating a lot of spicy foods, frequent use of steroids, excessive amounts of calcium in the blood (hypercalcemia), family background of peptic ulcers, among others.
In most patients, a peptic ulcer can be treated successfully. However, when it is not diagnosed or treated on time, it can be complicated with the development of stomach and duodenum cancer or stomach and duodenum perforation (which is a surgical emergency).
One property that makes H. pylori so infectious is its preference for the gastric epithelium (tropism). Likewise, H. pylori can survive in low pH conditions and can increase the
digestive acid production to achieve a low pH in parts of the body where it is usually higher (like the duodenum) due to the inhibition of bicarbonate secretion.
Although this bacterium can survive in acid media, it starts colonizing the stomach antrum, where the mucosal surface has a higher pH and then it spreads progressively to the rest of the stomach. During the initial stages of H. pylori infection, the transition zone can be defined as the space between normal and atrophic epithelium. As the infection progresses, the atrophic area can present abnormal parietal cells, which is called metaplasia, whereby it is considered that the degree of atrophy can indicate the severity of the infection.
When the infection spreads to all the layers of the stomach and affects different parts of it, (body, antrum, and fundus) it is denominated pangastritis, which is closely related to an increase in the risk of having gastric cancer, so treating the H. pylori infection can stop the spreading of infection along the entire stomach and duodenum and, in consequence, the development of cancer.
Finally, when H. pylori infection affects all the stomach layers, any minimal harmful agent can produce the stomach or duodenal perforation, which produces the exit of the stool to the abdomen and, consequently, an important abdominal infection (peritonitis) which must be treated immediately with surgery and profuse abdominal lavage.