H. pylori infection occurs when a bacterium called Helicobacter pylori (H. pylori) thrives in your stomach or the first part of your small intestine.
H. pylori infection may be present in about half the people in the world. In industrialized countries the infection rate is about 20 percent to 30 percent, but in developing countries the infection rate may exceed 70 percent. However, most people who carry the bacteria experience no signs or symptoms of infection.
H. pylori infection is the most common cause of stomach ulcers, and it also causes inflammation of the stomach lining. H. pylori infection may also contribute to stomach cancers and other digestive system cancers.
Antibiotics used to eradicate H. pylori bacteria are usually part of a multiple-drug strategy to treat disorders caused or worsened by H. pylori infection.
Although most cases of H. pylori infection produce no signs or symptoms, the toxic properties of the bacterium can lead to disorders of the stomach or the first part of your small intestine (duodenum). Signs and symptoms associated with H. pylori infection can vary in severity and duration depending on which disorder is present. If you have an H. pylori-related disease, you may experience the following signs and symptoms:
- An ache or burning pain in your abdomen
- A change in appetite with weight loss
- Nausea
- Vomiting
- Frequent burping
- Bloating
- Bloody vomit or vomit that looks like coffee grounds
- Bloody or black tarry stools
Disorders associated with H. pylori infection
It's not entirely clear why some people with H. pylori infection remain apparently healthy and some develop digestive system disorders. It's also unclear why some people exhibit milder disorders and others more severe disorders. Factors that may make a difference include varying degrees of virulence in different strains of H. pylori and genetic factors that may make some people more vulnerable to one of the following H. pylori-related disorders:
- Stomach and duodenal ulcers are open sores in the lining of your stomach or the first part of the small intestine (duodenum). H. pylori infection causes the majority of these ulcers. The most common sign of an ulcer is a frequent burning pain in your abdomen. The pain occurs most often when your stomach is empty and may last only a few minutes or several hours.
- Gastritis is inflammation of your stomach's lining. While signs and symptoms are often similar to those of ulcers, you may have gastritis with no apparent problems at first. H. pylori infection can cause a chronic inflammatory response that over time damages the lining of your stomach and results in the loss of acid-producing glands in your stomach. These changes can increase your risk of developing stomach cancer.
- Stomach cancer is a disease in which abnormal cells in your stomach divide without control. H. pylori infection is a strong risk factor for certain types of stomach cancer. Most signs and symptoms occur only after the cancer is fairly well advanced. Additional problems associated with cancer may include a bloated or full feeling after a very small meal, difficulty swallowing, breath odor, excessive gas or a general decline in health.
- Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the development of a cancerous tumor from white blood cells (lymphocytes) in the lining of your stomach. H. pylori infection greatly increases your risk of gastric MALT lymphoma, and nearly all people with the disease are infected with this bacterium.
- Nonulcer dyspepsia is stomach pain or discomfort not caused by an ulcer or another identifiable disorder that would result in the pain. The relationship between H. pylori infection and nonulcer dyspepsia isn't clear.
Causes
H. pylori bacteria enter your body through your mouth and pass into your digestive system. The stomach is generally a very hostile environment for many bacteria. But the H. pylori bacterium is especially well-adapted for survival in the stomach. It produces an enzyme that, through a series of biochemical processes, creates a low-acid buffer zone for itself.
Many people contract H. pylori infection as a child, and the infection persists into adulthood, but adults also can contract H. pylori.
The bacteria seem to be transmitted from one person to another through contact with saliva. You could, for example, contract an H. pylori infection by sharing an eating utensil with an infected person.
It could also be contracted from contact with fecal matter that harbors H. pylori. This can result from generally poor sanitary conditions or from poor hand-washing habits.
These types of transmission occur most often in circumstances with crowded living arrangements, inadequate sewage removal, poor personal hygiene or a lack of clean water.
Treatments and drugs
Treatment for H. pylori infection is always part of a multiple-treatment strategy to treat the disorder caused by the infection.
Antibiotics
Your doctor will most likely prescribe a 14-day regimen of two antibiotics to eradicate H. pylori bacteria. Common combinations are:
- Clarithromycin (Biaxin) and amoxicillin (Amoxil, Trimox)
- Metronidazole (Flagyl) and amoxicillin (Amoxil, Trimox)
- Metronidazole (Flagyl) and tetracycline (Sumycin)
It's important to complete the full course of prescribed antibiotics as directed by your physician, even when you're feeling better. Failure to follow the treatment guidelines may not completely eradicate the infection and increases your risk of antibiotic-resistant strains of H. pylori.
Your doctor may use either a breath test or stool antigen test to determine whether the antibiotic treatment has eliminated the H. pylori infection.
While the antibiotic treatment can completely eradicate H. pylori bacteria, an infection can recur later.
Other treatments
If you're taking a double-antibiotic course for an ulcer or gastritis, your doctor will also prescribe one or more medications to alleviate symptoms and promote healing. The most commonly prescribed drugs include:
- Proton pump inhibitors. These prescription medications suppress acids by shutting down "pumps" in acid-producing cells. Examples include omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex) and esomeprazole (Nexium).
- Histamine-2 (H-2) blockers. These reduce the amount of hydrochloric acid released into your digestive tract. Available by prescription or over-the-counter (OTC), H-2 blockers include ranitidine (Zantac), famotidine (Pepcid), cimetidine (Tagamet) and nizatidine (Axid).
- Bismuth subsalicylate (Pepto-Bismol). This protects the lining of your stomach and duodenum.
If you're diagnosed with stomach cancer or gastric MALT lymphoma, your doctor may prescribe a double-antibiotic treatment in addition to the options you may have for treating the cancer, such as surgery, radiation therapy or chemotherapy. Eradication of the H. pylori infection may improve cancer treatment outcomes and help prevent the recurrence of cancer.
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