Pathophysiology of Zollinger-Ellison
Zollinger-Ellison disease is a group of pathologic conditions caused by hypersecretion of gastric acid secondary to a gastrinoma
Signs and Symptoms
1) peptic ulcer (often in second to fourth part of the duodenum or in the jejunum) 2) diarrhea (often steatorrhea-like) 3) gastric bleeding/hematemesis 4) melena 5) duodenal perforation 6) epigastric tenderness
Characteristic Test Findings
Laboratory – 1) fasting serum gastrin > 1000 pg/mL 2) basal acid output > 15 mEq/h 3) hypercalcemia (if part of MEN-1) 4) BAO to MAO > 0.6 5) increase in gastrin level in secretin-stimulation test Radiology – 6) hypertrophic gastric folds similar to Menetrier’s disease on upper GI series 7) gastrinoma often not seen on CT scan or MRI 8) visceral angiography may show tumor blush and enable localization 9) somatostatin receptor scintigraphy and endoscopic ultrasound have good sensitivity and specificity for localization
Histology/Gross Pathology
1) gastrinomas in Zollinger-Ellison disease are frequently extrapancreatic (in gastrinoma triangle) or in lymph nodes 2) histology does not predict metastatic potential
Associated Conditions
1) MEN-1 (hyperparathryoidism, pituitary tumors, pancreatic endocrine tumors) 2) gastric outlet obstruction 3) peptic esophageal injury caused by gastroesophageal reflux
Inheritance/Epidemiology
1) Zollinger-Ellison disease is more common in males 2) 75% occur sporadically; 25% occur as part of MEN-1 3) 50% are malignant 4) 66% of gastrinomas in MEN-1 are multiple
Treatment
1) non-metastatic – localize and then resect for cure 2) to palliate until surgery proton pump inibitors are used (omeprazole and lansoprazole) 3) metastatic – palliative chemotherapy (streptozocin, 5-FU, doxorubicin)
Tips for USMLE
1) if Zollinger-Ellison disease occurs as part of MEN-1 (parathyroid, pituitary, gastrinoma in pancreas) then parathyroids are operated on first 2) in normal individuals, the secretin-stimulation tests causes gastrin to fall 3) in other causes of hypergastrinemia (antral G-cell hyperplasia) the secretin-stimulation test causes gastrin to remain the same; in gastrinoma, gastrin increases 4) postbulbar ulcers are highly suggestive of gastrinoma
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