Situations in which a gastrinoma should be suspected include:

• if a patient has unusual peptic ulcer disease - for example
  • multiple refractory peptic ulcers, complications of peptic ulcers, refractory oesophageal reflux symptoms, oesophageal strictures, oesophageal ulcers or ulcers in unusual locations
• if a patient has a duodenal ulcer but Helicobacter pylori infection is not present
• if there is a failure to heal a duodenal ulcer by the eradication of H. pylori or with acid suppressant treatment
• if a patient has a peptic ulcer(s) and also a gastric fluid pH of less than 2.5 (together with simultaneously elevated fasting serum gastrin levels)
• if a patient has peptic ulcer(s) and a pancreatic endocrine tumour
• if there is other endocrine disease present
• if there is a family history of other endocrinopathies, particularly nephrolithiasis and hypercalcaemia, or when there is a family history of MEN-I
• if a patient has chronic diarrhoea that persists during fasting or decreases with gastric acid antisecretory treatment

Reference:

1. de Herder WW and Lamberts SWJ. Best Practice & Research Clinical Endocrinology & Metabolism 2004; Volume 18(4): 477-495.