Gastrointestinal · Year 2 · from Gastrointestinal
Case 1: Zollinger-Ellison Syndrome
Patient Presentation
Demographics: 48-year-old male
Chief Complaint: Recurrent peptic ulcers and chronic diarrhea
History of Present Illness: The patient has had three separate episodes of peptic ulcer disease over the past 4 years, requiring hospitalization twice for upper GI bleeding. He reports persistent epigastric burning despite continuous high-dose PPI therapy. He also experiences 4-5 watery, non-bloody stools daily and has lost 15 pounds over the past year. He tested negative for H. pylori on multiple occasions.
Past Medical History: No prior medical conditions before ulcer disease onset
Family History: Father diagnosed with kidney stones at age 50
Physical Examination
- Vital Signs: BP 124/78 mmHg, HR 76 bpm, BMI 23
- General: Thin male, appears uncomfortable
- Abdomen: Mild epigastric tenderness, no peritoneal signs, no palpable masses
- Skin: No rashes
Workup and Results
- Upper Endoscopy: Multiple duodenal ulcers (D1 and D2), one jejunal ulcer (unusual location)
- Fasting Serum Gastrin: 1,850 pg/mL (normal <100 pg/mL)
- Gastric pH: 1.2 (low pH excludes achlorhydria as cause of hypergastrinemia)
- Secretin Stimulation Test: Paradoxical gastrin rise of 280 pg/mL (diagnostic)
- CT Abdomen: 2.1 cm mass in the pancreatic head
- EUS with FNA: Neuroendocrine tumor confirmed
CT scan showing a hypervascular mass in the pancreatic head (arrow) within the gastrinoma triangle, consistent with a gastrin-secreting neuroendocrine tumor.
Image Source: Case courtesy of Radiopaedia.org
Diagnosis
Zollinger-Ellison Syndrome (Gastrinoma)
Clinical Correlation to Gastric Secretion Physiology
Gastrinomas autonomously secrete gastrin, bypassing normal feedback regulation. Normally, low gastric pH (<3) stimulates somatostatin release from D cells, which inhibits gastrin release from G cells. Gastrinomas are not subject to this feedback. The resulting hypergastrinemia causes massive stimulation of parietal cells, producing acid hypersecretion. This explains multiple ulcers, ulcers in unusual locations (distal duodenum, jejunum where acid overcomes buffering capacity), and refractory symptoms despite PPIs. Diarrhea occurs because excess acid inactivates pancreatic lipase and damages small intestinal mucosa. The secretin stimulation test is diagnostic because secretin normally inhibits gastrin release, but paradoxically stimulates gastrinomas.
Treatment
- High-dose PPI (often 2-3 times standard dose) for acid control
- Surgical resection of localized tumor for potential cure
- Screen for MEN1 (parathyroid hormone, calcium, prolactin)
- Somatostatin analogs (octreotide) for unresectable disease
- Long-term surveillance for metastatic disease