Pernicious anemia is still a neglected disorder in many medical contexts and is underdiagnosed in many patients. Pernicious anemia is linked to but different from autoimmune gastritis. Pernicious anemia occurs in a later stage of autoimmune atrophic gastritis when gastric intrinsic factor deficiency and consequent vitamin B12 deficiency may occur. The multifaceted nature of pernicious anemia is related to the important role of cobalamin, which, when deficient, may lead to several dysfunctions, and thus, the proteiform clinical presentations of pernicious anemia. Indeed, pernicious anemia may lead to potentially serious long-term complications related to micronutrient deficiencies and their consequences and the development of gastric cancer and type 1 gastric neuroendocrine tumors. When not recognized in a timely manner or when pernicious anemia is diagnosed with delay, these complications may be potentially life-threatening and sometimes irreversible. The current review aimed to focus on epidemiology, pathogenesis, and clinical presentations of pernicious anemia in an attempt to look beyond borders of medical specialties. It aimed to focus on micronutrient deficiencies besides the well-known vitamin B12 deficiency, the diagnostic approach for pernicious anemia, its long-term complications and optimal clinical management, and endoscopic surveillance of patients with pernicious anemia.

Objectives The management of individuals with gastric intestinal metaplasia (GIM) includes biopsies for its staging and to diagnose Helicobacter pylori (Hp). Advanced-stage GIM can be estimated by endoscopy through EGGIM, and a new device permits the real-time assessment of ammonia for the identification of Hp infection. The aim of this study was to assess the simultaneous use of EGGIM and real-time assessment of ammonia to avoid biopsies and reduce the burden of care in clinical practice. Methods A multicentre study involving 101 consecutively enrolled patients [52% male; 65(18–85) years]. During endoscopy, gastric juice was aspirated and analysed; EGGIM was determined in real-time. Targeted biopsies were performed and histopathological assessment was used as gold standard. Results Advanced-stage GIM were detected in 14.9% of patients and Hp infection in 18.8%. EGGIM showed for advanced-stage GIM a sensitivity, specificity and NPV of 86.7%, 84.9% and 97.3%, whilst real-time assessment of ammonia, 83.3%, 78.2% and 95.4%, respectively. Gastric juice was insufficient in 5 (5.0%). Overall, 64 (67%) patients were correctly diagnosed by EGGIM and real-time assessment of ammonia. If the 47 (49%) patients negative to both assessments would have avoided biopsies, only 4 (4.2%) would have been missed: two with advanced-stage GIM and two with Hp infection. Conclusion The combination of endoscopic assessment and real-time analysis of Hp allows the exclusion of advanced-stage GIM or Hp infection without the need of biopsies in a significant proportion of individuals. This may allow in specific situations to abstain from biopsies reducing the burden of care.

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Gender differences and microbiota are gaining increasing attention. This study aimed to assess gender differences in gastric bacterial microbiota between subjects with healthy stomachs and those with autoimmune atrophic gastritis. This was a post hoc analysis of 52 subjects undergoing gastroscopy for dyspepsia (57.7% healthy stomach, 42.3% autoimmune atrophic gastritis). Gastric biopsies were obtained for histopathology and genomic DNA extraction. Gastric microbiota were assessed by sequencing the hypervariable regions of the 16SrRNA gene. The bacterial profile at the phylum level was reported as being in relative abundance expressed as 16SrRNA OTUs (>0.5%) and biodiversity calculated as Shannon-diversity index-H. All data were stratified for the female and male gender. Results showed that women with healthy stomachs had a higher gastric bacterial abundance and less microbial diversity compared to men. Likely due to hypochlorhydria and the non-acid intragastric environment, autoimmune atrophic gastritis seems to reset gender differences in gastric bacterial abundance and reduce biodiversity in males, showing a greater extent of dysbiosis in terms of reduced biodiversity in men. Differences between gender on taxa frequency at the phylum and genus level in healthy subjects and autoimmune atrophic gastritis were observed. The impact of these findings on the gender-specific natural history of autoimmune atrophic gastritis remains to be elucidated; in any case, gender differences should deserve attention in gastric microbiota studies.