Zollinger-Ellison Syndrome

Zollinger-Ellison syndrome (ZES) is an acid-hypersecretion disorder caused by one or more gastrinomas, which are gastrin-secreting neuroendocrine tumors. Most arise in the duodenum or pancreas. Excess gastrin continuously stimulates gastric parietal cells, so the clinical picture is not simply “another ulcer.” It is a pattern of unusually persistent acid injury: recurrent or multiple ulcers, ulcers in atypical sites, severe reflux disease, diarrhea, or malabsorption despite ordinary treatment. The nurse’s first clinical insight is to connect these findings rather than assess each one in isolation. The second is medication safety. Proton-pump inhibitors (PPIs) can elevate gastrin and chromogranin A, complicating testing, but abruptly stopping a PPI in a patient with true gastrinoma can unleash rebound acid hypersecretion and precipitate ulceration, bleeding, or perforation. Diagnostic planning must therefore protect acid control while specialists determine how testing can be interpreted safely.