H. Pylori Infection

A large number of reports have been produced on HP and its pathogenetic potential. In fact, although peptic ulcer disease is the most studied disease related to HP infection, this bacterium is seemingly involved in the pathogenesis of several extragastric diseases, such as mucosa-associated lymphoid tissue lymphomas (MALTomas), coronaritis, gastroesophageal reflux disease, iron deficiency anemia, skin disease, and rheumatological conditions.

A strong association has been reported between HP infection and gastric lymphoma and adenocarcinoma of the body and antrum of the stomach. Currently, whether HP eradication can decrease the risk of cancer remains unknown.

Mortality/Morbidity

The mortality rate related to HP infection is not precisely known, but it seems to be minimal (i.e.: approximately 2- 4% of all infected people). Mortality is due to the complications of the infection, such as gastric ulcer perforation or MALTomas of the GI tract. Otherwise, the morbidity of HP infection can be very high.

Age

HP infection may be acquired at any age. According to some epidemiologic studies, this infection is acquired most frequently during childhood. Children and females have a higher incidence of reinfection (5-8%) than adult males.

History/Physical

No significant differences in the presence and frequency of symptoms, such as nausea, vomiting, pain, heartburn, or diarrhea, occur in patients who are infected with HP and patients who are not. No specific clinical signs have been described in patients with HP infection.

Lab Studies

HP fecal antigen test: It has been reported to be very specific (98%) and sensitive (94%). The results are positive in the initial stages of infection and can be used to detect eradication after treatment.

Carbon 13 urea breath test: The carbon 13 urea breath test (UBT) is based on the detection of the products created when urea is split by the organism. Problems include false-negative results due to intake of antibiotics, bismuth, histamine 2 (H2) blockers, or proton pump inhibitors.

HP serology: The serology test has a high (>90%) specificity and sensitivity. It is useful for detecting a newly infected patient, but it is not a good test for follow-up.

Imaging Studies

Imaging studies are not helpful in the diagnosis of HP infection. Otherwise, they may be useful in patients with complicated disease (e.g.: ulcer disease, gastric cancer, MALToma).

Other Tests

An esophagogastroduodenoscopy (EGD) is often necessary in patients with symptoms of peptic ulcer disease in order to view the condition of the mucosal lining of the stomach and duodenum and to obtain biopsy specimens from the gastric antrum. An echography associated with an EGD is mandatory in patients with biopsy results that are positive for gastric MALTomas in order to allow a more precise staging of the disease. Peptic ulcer disease and gastric cancer may manifest with the same symptoms, and the only way to differentiate them is to view the lesion and perform a histologic examination on biopsy specimens.

Staging

Although a staging system for the HP infection does not exist, some steps of the disease are well described. The first step is chronic gastritis, followed after a time by the second step, atrophic gastritis. The third step is intestinal metaplasia, which may evolve into dysplasia. The last step in this process is gastric adenocarcinoma. As reported above, ultrasound and EGD should be considered in patients with gastric MALTomas in order to allow a more precise staging of the disease.

Treatment

Only treat patients who have a test result positive for HP infection. Carefully educate patients regarding the importance of completing the prescription and about the potential adverse effects of the medication. Importantly, consider possible antibiotic resistance when selecting the treatment regimen.

Administer triple therapies for 10-14 days. The treatment regimens are omeprazole, amoxicillin, and clarithromycin (OAC) for 10 days; bismuth subsalicylate, metronidazole, and tetracycline (BMT) for 14 days; and lansoprazole, amoxicillin, and clarithromycin (LAC), which has been approved for either 10 or 14 days of treatment. Macrolide resistance in patients with HP infection is an important problem. An emerging and increasing problem in many Western countries is the fact that some HP strains in children are resistant to the antibiotic clarithromycin. The causes are not known.

Deterrence/Prevention

Risk is increased for patients who have an HP infection and whose first-degree relatives have a history of gastric cancer, even if they are asymptomatic. Also, persons emigrating from geographic areas with a high incidence of gastric cancer have an increased risk. Consider any patient with precancerous lesions of the stomach (i.e.: intestinal metaplasia) for treatment of HP.

Complications

Gastric adenocarcinoma is the most severe consequence of an HP infection. Gastric MALToma may be treated with HP eradication therapy and has a better prognosis than gastric adenocarcinoma. HP infection is associated with squamous cell esophageal cancer. HP may play an important role in idiopathic thrombocytopenic purpura.

Prognosis

Prognosis is usually excellent, even in patients with complications such as gastric MALToma. However, the prognosis becomes poor for patients who develop squamous cell esophageal cancer or gastric carcinoma.

Medical-Legal Concerns

Consider performing an EGD before prescribing a treatment for peptic ulcer disease. Peptic ulcer disease and gastric cancer may manifest with the same symptoms, and a correct diagnosis is mandatory to avoid legal claims. Also consider that in a small number of cases (2%), peptic ulcer disease and gastric carcinoma, even ulcerated, may coexist.

Another problematic area is when HP infection occurs during pregnancy. In this case delay the treatment until after delivery because of the adverse teratogenous effects of some drugs used in the therapeutic protocols for HP eradication. In addition, delaying a new pregnancy for at least 1 month after the end of treatment may be advisable.