This is the first study assessing clinical, endoscopic and histological characteristics of Hp + and Hp- Armenian children with recurrent abdominal pain and/or dyspepsia.
Prevalence of Hp in symptomatic children differs from country to country: 34.6% in Ethiopia (15), 25% in Hon Kong (14), 24.5% in Bulgaria (13), 64.6% in Egypt (16). The prevalence is mainly depending on socio-economic status and number of family members. There is only one study assessing seroprevalence of Hp infection in symptomatic adults with dyspeptic symptoms in Armenia showing of 49% being positive . In our cohort of patients with recurrent abdominal pain and/or dyspepsia Helicobacter pylori was diagnosed in 70.6%. This high prevalence might be explained by the fact of acquiring infection in the childhood, developing status of Armenia and intrafamilial distribution of infection (high number of family members with gastritis, PUD and dyspeptic symptoms).
There are different concepts on decision of making endoscopy in pediatric patients with repeated or chronic abdominal pain and dyspepsia. Hyams JS et al. found that duration of vomiting and other dyspeptic symptoms more than 1 year were risk factors for mucosal inflammation of upper GI tract . Other study suggested importance of EGD in patients with symptom duration more than 6 months, severe symptoms affecting sleep and family history of peptic ulcer disease or Hp infection .
Our patients were referred to medical attention with symptoms persisting median more than a year in both groups. According to the current literature data, there is no significant difference in symptoms of Hp positive vs Hp negative children shown in symptomatic pediatric population [13, 14, 15, 16]. In contrast to published studies from other countries our study showed that night time abdominal pain and regurgitaion were statistically more common in Hp + children with PUD and/or aphthous lesions in the upper GI tract.
Antral nodularity is one of the signs of Hp associated gastritis and maybe associated with higher grade of gastritis in children [ 23, 25, 26]. According to our data erosive lesions in the stomach and duodenum were statistically more common endoscopic findings in Hp + patients, gastric nodularity were exclusively found in Hp + group.
Low incidence of ulcers in Hp positive children was reported in Chinese  7.2% and European (6.8%) pediatric patients . In contrast to it, in developing countries PUD prevalence in Hp positive children reaches 33.2% [18, 19]. Our study showed low incidence of PUD in Hp + Armenian children, which might be explained by treatment received before admission. 2 Hp - patients had ulcers, probably due to GI bleeding or false negative Hp test.
Hp infection has been reported was significantly associated with chronic (88.5%) and active (63%) gastritis . Data obtained by Canan O. et al, showed that in two third of the patients with nonorganic dyspepsia had normal histological data, while one third had mild or chronic non-active inflammation of the mucosa . Similarly in our cohort of patients the main histological findings in Hp + patients were chronic active and non-active gastritis and duodenitis, while in Hp- patients mainly histologically normal mucosa was seen. Nevertheless more than half of Hp- negative patients had chronic non-active inflammation in the stomach.
Our study showed that serious histologic changes were exclusively seen Hp + children, and equally observed in both patients with ulcerative/aphthous and superficial changes. This is contrast with the review analyzing atrophy and intestinal metaplasia in children, where different rates are mentioned and this changes are not always connected with Hp infection .