Collagenous Gastritis: A Rare Cause of Hemorrhagic Shock.

Collagenous gastritis (CG) is a rare condition comprised 2 phenotypes-pediatric and adult onset. While adult CG often presents with diarrhea, pediatric CG more often manifests with iron deficiency anemia and abdominal pain. Of the relatively few cases described since discovery, treatment has involved oral iron, proton-pump inhibitors, and close follow-up. While 22.5% of pediatric CG involves some form of gastrointestinal bleeding, massive hemorrhage resulting from CG has not previously been described. We present a case of refractory CG diagnosed on endoscopy after hemorrhagic shock due to an acute gastrointestinal bleed requiring both initial and off-label step-up therapy.