PMON40 A Rare Etiology of Chronic Diarrhea: Zollinger-Ellison Syndrome

INTRODUCTION: Zollinger-Ellison Syndrome (ZES) is a rare etiology of chronic diarrhea caused by a gastrin-secreting neuroendocrine tumor. Early suspicion can prevent multiple readmissions for recurrent diarrhea thus improving clinical outcomes through prompt diagnosis and treatment, as the following case highlights. CASE PRESENTATION: A 74-year-old African-American female with hypertension and chronic atrial fibrillation presented to the ED complaining of watery, non-bloody diarrhea for the past 3 weeks. She reports her symptoms worsened after completing a course of amoxicillin for pharyngitis one week prior. On further questioning, she reported intermittent diarrhea for over 20 years lasting approximately two days per episode. She denied recent travel, sick contacts, pet reptiles, and recent ingestion of undercooked meat. On arrival, she was afebrile and hemodynamically stable. She was admitted for an acute kidney injury with an elevated creatinine of 3.23 mg/dL (N: 0.6-1.1 mg/dL) due to dehydration. Her renal function improved with fluids, but she developed bloody diarrhea for which gastroenterology was consulted. Stool studies were negative for Shiga-toxin, C. difficile, lactoferrin, and parasites. Computed Tomography of the abdomen showed enteritis with fluid noted throughout the colon consistent with colitis. Unprepped colonoscopy revealed blood throughout the length of the colon, suggestive of an upper gastrointestinal bleed. Esophagogastroduodenoscopy (EGD) revealed multiple bleeding duodenal ulcers controlled with hemostasis. Her symptoms improved and she was discharged home on oral pantoprazole, and told to follow up outpatient. Two weeks later, she denied any new episodes of diarrhea, and a random serum gastrin level was elevated at 413 pg/mL (N: <180 pg/mL). Repeat gastrin level off pantoprazole for 7 days was also elevated at 678 pg/mL, and a serum Chromogranin A level was elevated at 629 pg/mL (N: <390 pg/mL). Repeat EGD found her Gastric pH to be 1 with multiple non-bleeding duodenal ulcers. Somatostatin receptor scintigraphy revealed a high intensity signal consistent with a duodenal gastrinoma causing ZES. She elected for surgical resection, and was discharged home on high dose pantoprazole. Three months later, she stated that her diarrhea had completely resolved. CONCLUSION: This case confirms ZES as a rare cause of chronic diarrhea in the setting of multiple duodenal ulcers refractory to proton pump inhibitors. Diagnosis can be made with a fasting serum gastrin level >1000 pg/mL or >400 pg/mL with a gastric pH <1. A Secretin Stimulation Testing can also be used. Treatment starts with high dose proton pump inhibitors, octreotide for hormonal regulation, and surgical resection if necessary. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.