Overview of H. Pylori Infection

Bacteria linked to stomach ulcers and cancer

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Helicobacter pylori (H. pylori) is a corkscrew-shaped bacteria that was identified in 1982 as a principal cause of stomach ulcers and chronic gastritis, conditions which were formerly believed to be caused by stress and poor diet. Symptoms of H. pylori may include stomach pain, bloating, nausea, and tarry stools. Blood, stool, and breath tests can be used to confirm the infection and may be followed by an endoscopic exam to look directly inside the stomach.

H. pylori is believed to be present in the upper gastrointestinal tract of around 50 percent of the world’s population. Of these, over 80 percent of cases are entirely without symptoms. Of those who are symptomatic, an H. pylori infection is associated with an increased risk of stomach cancer.

While an H. pylori infection typically requires combination antibiotic therapy, growing rates of antibiotic resistance have made eradication of the bacteria all the more difficult.

Symptoms

The presence of H. pylori in the upper gastrointestinal tract is not inherently associated with disease. According to epidemiologic research from the University of Bologna, as many as 85 percent of affected individuals will never experience symptoms of any sort.

Those who do will typically develop acute gastritis, an inflammatory condition characterized by bouts of abdominal pain and nausea. Over time, this may progress into chronic gastritis in which the symptoms are persistent. Common signs and symptoms include:

  • Stomach pain
  • Nausea
  • Bloating
  • Belching
  • Loss of appetite
  • Vomiting

The pain is most often experienced when the stomach is empty, between meals, or the early morning hours. Many describe the pain as "gnawing" or "biting."

Stomach Ulcers

People with an H. pylori infection have between a 10 percent and 20 percent lifetime risk of a stomach ulcer. This most often occurs in the stomach itself, resulting in a gastric ulcer, or the pyloric antrum connecting the stomach to the duodenum, resulting in a duodenal ulcer.

You can often tell which ulcer is which by the timing of symptoms. A gastric ulcer (also known as a peptic ulcer) will usually cause pain shortly after eating, while the pain tends to develop two to three hours after eating if the ulcer is duodenal.

The severity of symptoms can vary and will typically overlap with those of gastritis. Severe ulcers may trigger a cascade of symptoms, some of which are directly related to gastric bleeding and the development of anemia. Common signs and symptoms include:

  • Black stool (a characteristic sign of bleeding)
  • Blood in stool (usually if the bleeding is profuse)
  • Fatigue
  • Shortness of breath
  • Difficulty breathing
  • Lightheadedness or fainting
  • Vomiting of blood

Emergency medical attention should be sought if symptoms like these develop.

How Does H. Pylori Cause Peptic Ulcers?

Stomach Cancer

The most common risk factor associated with stomach cancer is H. pylori infection, accounting for around 60 percent of cases. With that being said, the lifetime risk in those infected hovers only between 1 percent and 2 percent.

The main contributing factor is the persistent inflammation associated with chronic gastritis, which can trigger pre-cancerous changes in the lining of the stomach. An H. pylori infection will not generally be the sole cause but rather a contributing factor alongside family history, obesity, smoking, and a diet rich in salted, smoked, or pickled foods.

Stomach cancer is often entirely without symptoms in the early stages. Indigestion, heartburn, and a loss of appetite are not uncommon. As the malignancy progresses, symptoms may include:

  • Persistent weakness and fatigue
  • Bloating after meals
  • Nausea and vomiting
  • Difficulty swallowing
  • Diarrhea or constipation
  • Blood in stools or tarry stools
  • Unexplained weight loss
  • Vomiting of blood

It is important to recognize these symptoms so that you can seek treatment as soon as possible. Because 80 percent of these malignancies are symptom-free in the early stages, most cases are only discovered after the cancer has already spread (metastasized) to the lymph nodes or beyond.

Causes

H. pylori is a microaerophilic bacteria, meaning that it requires little oxygen to survive. While the bacteria is contagious, it is still not entirely clear how it is spread. Most evidence suggests that it is transmitted via an oral-oral route (through the direct or indirect exchange of saliva) or a fecal-oral route (through contact with unsanitized hands or surfaces, or the drinking of contaminated water).

The rates of infection are far lower in North America and western Europe, where around a third of the population is believed to be affected. By contrast, the prevalence in eastern Europe, South America, and Asia is well in excess of 50 percent.

The age at which someone is infected appears to influence the risk of disease. People infected at a younger age are at a greater risk of atrophic gastritis in which the lining of the stomach develops scarring (fibrosis). This, in turn, increases the risk of gastric ulcers and cancer. By contrast, H. pylori infections acquired at an older age will more likely lead to a duodenal ulcer.

In the U.S. and other developed countries, H. pylori infection tends to occur at an older age. Due to strict public sanitary measures, only around 10 percent of infections in the U.S. occur in people under 30. The remainder is seen in older people, particularly those over 60, who account for around half of all infections.

Diagnosis

Having H. pylori is not a disease unto itself and, as such, routine screening is not recommended. It is only when symptoms develop that your doctor will want to confirm the presence of the bacteria and investigate any abnormal changes in the stomach.

H. pylori can usually be diagnosed with one of three minimally invasive tests:

  • Blood antibody tests can detect whether specific defensive proteins, known as antibodies, have been produced by the immune system in response to the bacteria.
  • Stool antigen tests look for direct evidence of the infection in a stool sample by detecting a specific protein, known as an antigen, on the surface of the bacteria.
  • Carbon urea breath tests are performed by breathing into a prepared packet 10 to 30 minutes after swallowing a tablet containing urea (a chemical comprised of nitrogen and a minimally radioactive carbon). H. pylori produces an enzyme that breaks down urea into ammonia and carbon dioxide (CO2). Excessive levels of CO2 will trigger a positive reaction, confirming the presence of the bacteria.

If these tests are inconclusive and your symptoms persist, your doctor may order an endoscopy to view your stomach and obtain tissue samples. Endoscopy is an outpatient procedure performed under sedation in which a flexible, lighted scope is inserted down the throat and into your stomach.

Once there, a tiny fibreoptic camera can capture digital images of the gastric lining. A special attachment at the end of the scope can pinch off tissue samples (known as a pinch biopsy) for analysis in the lab.

Common side effects of endoscopy include sore throat, upset stomach, heartburn, and prolonged drowsiness. In rare cases, gastric perforation, bleeding, and infection may occur. Call your doctor or seek emergency care if you experience fever, shortness of breath, tarry stools, vomiting, or severe or persistent abdominal pain following the procedure.

Follow-Up

Stomach ulcers can be positively diagnosed by direct visualizing the ulcerated tissue. If cancer is suspected, the tissue sample will be sent to a pathologist to either confirm or rule out the presence of cancer cells. If cancer is found, other blood tests (referred to as tumor markers) and imaging tests (such as a PET/CT scan) will be ordered to stage the disease and direct the course of treatment.

Differential Diagnoses

Low-level H. pylori infections are often missed by current diagnostic tools. To this end, efforts will often be made to exclude other possible causes if H. pylori cannot be confirmed. These may include:

Treatment

Typically speaking, H. pylori is not treated if it does not cause symptoms. In fact, research suggests that H. pylori may be beneficial to some people by suppressing the "hunger hormone" ghrelin and normalizing the excessive secretion of stomach acids.

According to a 2014 study from the University of Queensland, the eradication of H. pylori was associated with an increased risk of obesity. Other studies have suggested an inverse relationship between H. pylori and GERD in which the bacterial infection may very well reduce the severity of acid reflux.

If an H. pylori infection causes symptomatic disease, the treatment would be focused, firstly, on the eradication of the infection and, secondly, on the repair of any injury to the stomach.

Antibiotics

Eradication of H. pylori has proven difficult as increasing rates of antibiotic resistance have rendered many traditional therapies useless. Because of this, doctors today will take a more aggressive approach by combining two or more antibiotics with an acid-reducing drug known as a proton pump inhibitor (PPI). If a first-line therapy fails, additional combinations will be tried until all signs of the infection have been erased.

While drug selection can vary based on known patterns of drug resistance in a region, the therapeutic approach in the U.S. is typically described as follows:

  • First-line therapy involves a 14-day course of the antibiotics clarithromycin and amoxicillin used in combination with an oral PPI.
  • Second-line therapy would involve a 14-day course of the antibiotics tetracycline and metronidazole, an oral PPI, and bismuth subsalicylate tablets (such as chewable Pepto-Bismol) which help protect the stomach lining. Tinidazole is sometimes substituted for metronidazole.
  • Sequential therapy involves two separate courses of therapy. The first is conducted over five days with amoxicillin and an oral PPI. This is followed by a second five-day course comprised of clarithromycin, amoxicillin, and an oral PPI. Outside of the U.S. where the drug is approved, the antibiotic nitroimidazole is often added.

A number of other combinations may be explored involving different classes of antibiotics and durations of treatment. Some doctors will also incorporate oral probiotics, such as Lactobacillus- and Bifidobacterium-containing yogurt, into therapy, which may help suppress bacterial activity.

Ultimately, the success of any treatment depends on strict adherence to the prescribed therapy. Stopping short "when you feel better" only allows drug-resistant bacteria to escape and re-establish an even harder-to-treat infection. It is only by completely eradicating all traces of H. pylori that a sustained cure can be achieved.

Common and Serious Antibiotic Side Effects

Ulcer Treatments

Ulcers can often be treated at the time of the endoscopic diagnosis. When spotted, various instruments can be fed through the endoscope to either seal off a blood vessel with a laser or electrocautery (in which tissue is burned with an electrical current), or to inject epinephrine into the vessel to stop bleeding. A clamp attachment can also be used to hold the wound shut until the bleeding stops.

If these procedures are unable to stop the bleeding, surgery may be required. This is generally only pursued if there is a high risk of a gastric perforation. An active perforation is considered a medical emergency requiring immediate surgery. 

Surgery may include a partial gastrectomy in which part of the stomach is removed, often through laparoscopic (keyhole) surgery. Fortunately, advances in pharmaceutical and endoscopic treatments have made ulcer surgery an increasingly rare procedure in the U.S.

Coping

Even after H. pylori has been positively identified, it may take time—and several trial-and-error attempts—the cure you of the infection. During this time, you will want to take steps to avoid anything that can cause stomach upset or trigger the excessive production of acid.

Among some of the tips to consider:

  • Avoid aspirin and other NSAIDs that can cause stomach irritation and promote gastric bleeding.
  • Speak with your doctor if you are taking a blood thinner like warfarin. If appropriate, the drug may need to be stopped until the treatment has been successfully completed.
  • Do not overdose on iron supplements. While they can help treat anemia caused by gastric bleeding, overconsumption may trigger stomach upset.
  • Avoid caffeine, acidic foods, spicy foods, and carbonated beverages. Instead, focus on high-fiber fruits and vegetables, plain chicken and fish, and probiotic foods like yogurt and kombucha.
  • Explore stress reduction techniques that may help temper the production of stomach acid. These include mindfulness meditation, guided imagery, Tai chi, and progressive muscle relaxation (PMR).
  • Stay well hydrated, drinking around eight 8-ounce glasses of water per day. This may help dilute stomach acid.
  • Exercise can improve your energy levels and sense of well-being. But avoid overexerting yourself or performing exercises that either jostle or compress the stomach. Moderation is key.

    A Word From Verywell

    It is often difficult to avoid H. pylori given that the bacteria is so widespread and our understanding about the routes of infection remains limited. As a general rule, it is always wise to wash your hands regularly, to eat food that has been properly prepared, and to drink water from a safe, clean source. Beyond that, there are no official recommendations on how to avoid H. pylori infection.

    If you're experiencing symptoms of gastritis that either recur or fail to go away, ask your doctor to investigate H. pylori as a possible cause. The tests are quick and minimally invasive and may help direct you to effective and lasting treatment.

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