Define Zollinger-Ellison Syndrome. Describe its clinical features and management.

The Concept

Zollinger-Ellison syndrome is caused by a gastrin-secreting tumour (a gastrinoma), usually located in the pancreas or the duodenal wall. The mechanism is straightforward and explains every feature: the tumour releases excess gastrin, which massively stimulates the gastric parietal cells to produce excess acid, and this acid hypersecretion causes severe, unusual peptic ulceration. It is a rare but important cause of ulcer disease that is easily missed if not considered.

Clinical Features

The hallmark is peptic ulcers that are multiple, recurrent, refractory to standard treatment, and in atypical sites — for example ulcers extending into the second part of the duodenum or the jejunum. There is also diarrhoea (the large acid load damages the small bowel and inactivates pancreatic enzymes). Zollinger-Ellison syndrome should be suspected in any patient with severe, recurrent or H. Pylori-negative ulcers.

Association, Diagnosis & Treatment

About a quarter of cases occur as part of men 1 (with parathyroid and pituitary tumours), so this is screened for. Diagnosis rests on a raised fasting serum gastrin in the presence of high gastric acid, confirmed if needed by a secretin stimulation test (gastrin paradoxically rises). The tumour is then localised with imaging (CT/MRI, endoscopic ultrasound, somatostatin-receptor scintigraphy). Treatment is high-dose proton pump inhibitors to control acid, and surgical resection of the gastrinoma where it can be localised and is not metastatic.

WHY It Is Easily Missed

Zollinger-Ellison syndrome is important precisely because it hides among ordinary ulcers. It should be actively suspected when ulcers are multiple, in unusual sites, recurrent after adequate treatment, associated with diarrhoea, or occur without H. Pylori or NSAID use — otherwise the underlying gastrinoma is missed and the ulcers relentlessly recur despite standard therapy.

Management Detail

Acid control usually requires higher-than-standard doses of PPI, titrated to symptoms and acid output. Curative surgical resection is attempted for a localised, non-metastatic gastrinoma; where the tumour is part of men 1 or has metastasised (commonly to the liver), the emphasis shifts to acid control and management of the metastatic neuroendocrine tumour.

The Bottom Line

Zollinger-Ellison syndrome is a gastrinoma causing acid hypersecretion and multiple refractory ulcers with diarrhoea, diagnosed by a high fasting gastrin (± secretin test), linked to men 1, and treated with high-dose PPIs plus resection of the localised tumour.

Relation to Neuroendocrine Tumours

The gastrinoma of Zollinger-Ellison syndrome is a neuroendocrine tumour, and this shapes its behaviour and treatment. Many are found in the 'gastrinoma triangle' around the head of the pancreas and duodenum, may be small and multiple (especially in men 1), and can be malignant with metastases to the liver. This is why localisation uses specialised imaging such as somatostatin-receptor scintigraphy, and why management ranges from curative resection of a solitary tumour to long-term acid suppression and neuroendocrine-tumour therapy for metastatic disease.

Suspect it in multiple, distal or recurrent ulcers.

• Zollinger-Ellison syndrome = gastrin-secreting tumour (gastrinoma), usually pancreas/duodenum → excess gastrin → excess acid.
• Multiple, recurrent, refractory, atypically-sited peptic ulcers (± jejunal) + diarrhoea; suspect in severe/H. Pylori-negative ulcers.
• ~25% part of men 1 (parathyroid + pituitary tumours).
• Diagnose with raised fasting gastrin (+ secretin stimulation test); localise by imaging.
• Treat with high-dose PPIs + surgical resection of the tumour.