Marked Hypergastrinemia and Extreme Erythrocyte Sedimentation Rate Elevation in Autoimmune Atrophic Gastritis with Severe Iron Deficiency Anemia: A Case Report

ABSTRACT

Autoimmune atrophic gastritis causes loss of oxyntic glands, reduced acid secretion, compensatory hypergastrinemia, and impaired iron and vitamin B12 absorption. A 46‐year‐old woman with minimal gastrointestinal symptoms had fasting serum gastrin > 1800 ng/L, an erythrocyte sedimentation rate of 109 mm/h, hemoglobin 8.2 g/dL, and microcytosis. Anti‐parietal cell and intrinsic factor antibodies were positive. Endoscopy and Sydney‐protocol biopsies showed oxyntic‐restricted atrophy, preserved antral mucosa, and linear‐to‐micronodular enterochromaffin‐like‐cell hyperplasia; C‐reactive protein was normal, and computed tomography showed no pancreatic or duodenal mass. After iron and vitamin B12 replacement, hemoglobin rose to 11.0 g/dL, and the erythrocyte sedimentation rate fell to 60 mm/h, whereas gastrin remained > 1800 ng/L at the measured 12‐week follow‐up. The findings support autoimmune atrophic gastritis as the explanation for the hypergastrinemia and an anemia‐associated contribution to the raised erythrocyte sedimentation rate. This case reinforces the need to interpret severe hypergastrinemia in relation to gastric acid status and extreme erythrocyte sedimentation rate values in relation to hematological factors.