Prevalência da infecção por Helicobacter pylori em pacientes portadores de fibrose cística e avaliação das alterações endoscópicas e histológicas da mucosa gastroduodenal

Abstract

Cystic fibrosis (CF) is the most common recessive genetic disorder in the white population. The disease is caused by a mutation in the gene that codifies the protein Cystic fibrosis transmembrane conductance regulator (CFTR), leading to its disfunction and consequently altering the ionic component of the secretions. In CF patients, both duodenal and pancreatic secretion of bicarbonate are diminished and the duodenal pH is inferior than in healthy subjects. Bicarbonate secretion is the most important defense mechanism of the duodenum. Few studies on the prevalence of peptic ulcerin this population show normalor even reduced prevalence, giving rise to the CF paradox. Helicobacter pylori (H. pylori) infection is the major etiologic factor for duodenal ulcer disease. There are few studies inthe literature about the prevalence of H. pyloriinfection in CF patients and the results are controversial. OBJECTIVES:To determine the prevalence of H. pyloriinfection in CF patients and to evaluate the endoscopic and histological findings in the gastroduodenal mucosa of these patients. PATIENTS AND METHODS:32 adult CF patients (53,1% female, meanage: 29 years) were included in the study. All the patients were submitted to the 13C-urea breath test and serologic test (after withdrawn of oral and/or parenteral antibiotics and proton pump inhibitor for, at least 30 and 10 days, respectively) for the detection of H. pyloriinfection. Twenty patients were submitted to upper endoscopy with measurement ofintragastric pH (nine refused to perform the exam and it was contraindicated in three due to pulmonaryinsufficiency). Gastric and duodenal biopsies were performed in 18 patients (two had coagulation disorder). RESULTS:The prevalence of H. pylori infection was of 67,8% based on the serologic test and the prevalence of active infection was of 21,9%, based on the 13C-urea breath test. Upper endoscopy showed erosive esophagitis in 20% of the patients, erosive duodenitis in 15% and duodenal ulcer scar in 10%. The mean intragastric pH was 1,89 (SD:0,51). On the histology, 12/18 patients (66,7%) showed normal gastric mucosa and the majority of the patients, 17/18 patients (94,5%), showed active duodenal inflammation, with duodenal gastric metaplasia evident in 12/18 (66,7%) of the biopsies. The patients with gastric metaplasia had a more acidic intragastric pH compared with the others (p=0,028). CONCLUSIONS:The prevalence of H. pyloriinfection in adult CF patients is the same as that of the Brazilian population. Lower prevalence of active infection, low density of infection in the infected patients and inexpressiveinflammatory alterations in gastric mucosa but expressive inflammatory alterations in the duodenal mucosa suggest that H. pyloriinfection, prolonged use of antibiotics and insufficient duodenal neutralization of gastric acid are responsible for the gastroduodenal findings observed in CF.