17 | A case of autoimmune thyrogastric syndrome with pernicious anemia

C. Clementi¹, E. Caturelli², A. Domenicucci³, M. Martuscelli⁴, D. Ronconi⁵, G. Gimignani⁶ | ¹Casa di Cura "Santo Volto" Santa Marinella-Roma; ²Medicina Interna, ASL RM/4 Osp.San Paolo, Civitavecchia, Roma; ³Medicina Interna, ASLRM/4 Osp.San Paolo, Civitavecchia, Roma; ⁴Medicina Interna, ASL RM/4 Osp.Padre Pio, Bracciano; ⁵Medicina Interna, ASLRM/4 Osp.Padre Pio, Bracciano; ⁶Medicina Interna, ASLRM/4 Osp San Paolo, Civitavecchia, Roma.

Thyrogastric syndrome is the association between autoimmune atrophic gastritis and autoimmune thyroid disease, and they appear to share a complex pathogenetic mechanism involving genetic predisposition, embryological origin, and environmental factors.

We describe a case of autoimmune thyrogastric syndrome in an adult man aged approximately 50 years. The most significant clinical factors are impaired iron and thyroxine absorption, attributable to changes in gastric acidity and changes in the gastric microbiota, followed by the intestinal microbiota. Autoimmune atrophic gastritis is a disease characterized by loss of gastric glands with or without metaplasia, often resulting from Helicobacter pylori infection, but less frequently from autoimmune changes with the presence of antiparietal and anti-intrinsic factor antibodies; the diagnosis is histological. As in our case, there is an association of vitamin B12 deficiency with macrocytic anemia, iron deficiency with increased liver deposits (secondary hemosiderosis), and the presence of antithyroid peroxidase antibodies. Gastric atrophy is considered the first of a multi-stage precancerous cascade and ultimately the progression to gastric adenosine carcinoma. Indeed, patients with chronic atrophic gastritis develop low gastric acid production and hypergastrinemia, which over time leads to enterochromaffin-like cell hyperplasia and neuroendocrine tumors (carcinoid tumors). Thus, geriatrics can also be the cause of potentially serious consequences, such as anemia, micronutrient deficiencies, drug malabsorption, neurological disorders, and an increased risk of cancer. Therefore, management requires vigilance (follow-up) with periodic prevention, through endoscopic, histological, and imaging examinations, for gastric cancer and neuroendocrine tumors.