Infectious diseases

Helicobacter pylori

Helicobacter pylori is a gram-negative, curved bacillus and microaerophilic found in the gastric mucosa of the human stomach associated with various digestive diseases. Infection by H. pylori is one of the most common in humans and although it occurs worldwide, it is more common in developing countries and the prevalence decreases when socioeconomic level increases.

Clinical features: It is a well-established cause of gastric and duodenal ulcer and persistent infection is a risk factor for carcinoma and gastric lymphoma. The majority of infected people have no symptoms and only a small percentage come to develop the disease.

Diagnosis: There are different methods to diagnose an infection of H. pylori that can be invasive, if they require endoscopy for taking a gastric biopsy, or non-invasive. None of the methods are infallible and for choosing the most appropriate several factors should be considered: the aim of the diagnosis, the laboratory resources and the characteristics of the patient.

H. pylori causes an immune response, both local and systemic. The immune system responds with a transitory increase of IgM antibodies, followed by an increase of IgG and IgA levels, persisting during infection.
Since IgM antibodies are detected only temporarily, they have little diagnostic value. The main systemic response is IgG type so its detection is the most widely used diagnosis. However, in many countries the prevalence is high and therefore, complementary techniques are needed to reach a correct diagnosis. Regarding the diagnostic value of IgA immunoglobulins, there are discrepant opinions and does not seem to add more efficiency to the determination of IgG antibodies. An important advantage of serological methods is that are not affected by recent treatment with antibiotics or Proton pump inhibitors, which can induce false negative results with other methods.

The European Helicobacter Study Group recommends serological techniques in the primary health care field, in patients younger than 45 years old with symptoms of dyspepsia and no alarm signs such as anemia, weight loss, etc.

Treatment: Removal of the bacteria in the gastric mucosa by means of combined antibiotic treatment is associated with the resolution of histological lesions and clinical symptoms improvement, both in type B gastritis and peptic ulcerous disease.

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