This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'A 45-year-old gentleman has undergone truncal vagotomy and pyloroplasty for bleeding duodenal ulcer seven years ago. Now he has intractable recurrent symptoms of peptic ulcer. All of the following suggest the diagnosis of Zollinger Ellison syndrome, except: \nSelect and explain. \nA. Basal acid output of 15 meq/hour, B. Serum gastrin value of 500 pg/ml, C. Ulcers in proximal jejunum and lower end of esophagus, D. Serum gastrin value of 200 pg/ml with secretin stimulation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Diagnosis of ZES is made by secretin provocative test when serum gastrin value increases ≥ 200 pg/ml, within 15 minutes \nZollinger Ellison syndrome\n\nZES is caused by gastrin secreting gut neuroendocrine tumors (gastrinomas), which result in hypergastrinemia and acid hypersecretion.\nClinical situations that create suspicion for ZES are\nulcers in unusual locations, ulcers in second part of duodenum & beyond (includes the option c)\nulcers refractory to standard medical therapy\nulcer recurrance after acid reducing surgery.\nulcers presenting with frank complications (bleeding, perforation and obstruction) ulcers in the absence of H. pylori or NSAID ingestion.\ngiant ulcers (> 2 cm)\nmultiple duodenal ulcers\nulcers associated with diarrhoea\nulcer patient with hypercalcemia or family h/o ulcers.\nulcers with severe esophagitis.\nulcers associated with prominent gastric folds\nulcers with findings s/o MEN-1 (endocrinopathy, family h/o ulcers or endocrinopathy, nephrolithiasis)\n\nDiagnosis of ZES (gastrinoma)\n\nThe first step in evaluation of a patient suspected of having ZES or gastrinoma is to obtain as fasting gastrin level.\nAll gastrinoma patients have a fasting gastrin level > 150 pg/mL.\nThe next step is to assess acid secretion by measuring basal acid output (BAD) which should be ≥15 meq/h (normal < 4 meq/h)\n\nA gastric pH of ≥ 3.0 implies hypochlorhydria and excludes gastrinoma.\nGastrin Provocative tests\n\nIn a pt. with pH < 2.0 or BAO ≥ 15 meq/hr and fasting gastrin level > 1000 pg/mL, the diagnosis of LES is confirmed.\nWith pH < 2.0 or BAO ≥ 15 meq/L and lower gastrin levels (150-1000 pg/mL), a secretin stimulation test is perforfmed to distinguish LES from other causes of hypergastrinemia.\nA rise of \xa0≥200 pg/mL of serum gastrin level within 15 min of secretin injection, confirms ZES.', 'role': 'assistant'}]