Zollinger‑Ellison Syndrome (Type 2)

Overview

Zollinger‑Ellison syndrome (ZES) is a rare disorder in which one or more gastrin‑producing neuroendocrine tumors (gastrinomas) develop in the pancreas or duodenum. The excess gastrin stimulates the stomach to secrete large amounts of gastric acid, leading to severe peptic ulcer disease and related gastrointestinal problems.

There are two major forms:

• Type 1 (sporadic) ZES – usually isolated gastrinomas, often associated with chronic atrophic gastritis.
• Type 2 (MEN‑1‑associated) ZES – occurs as part of multiple endocrine neoplasia type 1 (MEN‑1), a hereditary syndrome that also predisposes patients to parathyroid and pituitary tumors.

Who it affects

• Both sexes equally, though MEN‑1 (type 2) may appear slightly more often in women.
• Typical age of presentation: 30–50 years for type 2, compared with 40–60 years for sporadic cases.

Prevalence

• Overall ZES: ≈1–3 cases per million people worldwide (Mayo Clinic, 2022).
• Type 2 accounts for roughly 15–20 % of all ZES cases, reflecting the prevalence of MEN‑1 (≈1 in 30,000 individuals) (NIH, 2023).

Symptoms

The hallmark of ZES is acid‑related disease, but symptoms can be variable because tumors may be small, multiple, or metastatic.

Gastrointestinal

• Recurrent or refractory peptic ulcers – often multiple, >3 cm, and located distal to the duodenum (duodenal bulb, jejunum).
• Abdominal pain – crampy, worsens after meals.
• Diarrhea – acidic chyme irritates the intestine; can be watery and occur several times daily.
• Steatorrhea (fatty stools) – pancreatic enzymes are inactivated by excess acid.
• Nausea / vomiting – may be from ulcer complications or gastric outlet obstruction.
• Gastrointestinal bleeding – melena or hematemesis from ulcer erosion.

Systemic / Metabolic

• Weight loss – due to malabsorption, chronic diarrhea, and reduced intake.
• Fatigue – secondary to anemia or electrolyte disturbances.
• Osteopenia/osteoporosis – chronic acid loss can impair calcium absorption (especially in MEN‑1 where hyperparathyroidism may coexist).

Signs related to MEN‑1 (type 2 specific)

• Hypercalcemia symptoms (kidney stones, bone pain) from primary hyperparathyroidism.
• Headaches, visual changes, or hormone excess from pituitary adenomas.

Causes and Risk Factors

Pathophysiology

Type 2 ZES arises when a germline mutation in the MEN1 tumor‑suppressor gene (chromosome 11q13) leads to loss of menin function. This predisposes neuroendocrine cells of the pancreas/duodenum to become gastrin‑secreting tumors.

Risk Factors

• Inherited MEN‑1 mutation – autosomal dominant; each child has a 50 % chance of inheriting the defect.
• Family history of MEN‑1–related tumors (parathyroid, pituitary, pancreatic neuroendocrine tumors).
• Smoking may increase the risk of neuroendocrine tumor progression, though data are limited.
• Chronic gastritis or Helicobacter pylori infection does not cause type 2 ZES (it is a risk for sporadic ulcers, not gastrinomas).

Diagnosis

Because the disease is rare and symptoms mimic common peptic ulcer disease, a high index of suspicion is essential, especially in patients with MEN‑1 or ulcer disease that fails standard therapy.

1. Clinical Evaluation

• Detailed history of ulcer disease, diarrhea, weight loss, and family history of MEN‑1.
• Physical exam for abdominal tenderness, signs of anemia, or hypercalcemia.

2. Laboratory Tests

• Fasting serum gastrin level – > 1000 pg/mL (normal < 100 pg/mL) is strongly suggestive. Levels between 100–1000 pg/mL require provocation testing.
• Secretin stimulation test – in ZES, gastrin paradoxically rises > 120 pg/mL after intravenous secretin (sensitivity ≈ 95%).
• Serum calcium, PTH, and vitamin D to evaluate MEN‑1‑related hyperparathyroidism.
• Basic metabolic panel, CBC, and iron studies to assess for anemia and electrolyte disturbances.

3. Imaging Studies

• Endoscopic ultrasound (EUS) – excellent for detecting ≤ 1 cm pancreatic/duodenal lesions.
• Multiphasic contrast‑enhanced CT or MRI – evaluates size, local invasion, and distant metastases (especially liver).
• Somatostatin receptor scintigraphy (Octreoscan) or 68Ga‑DOTATATE PET/CT – highly sensitive for neuroendocrine tumors, guides surgical planning.
• Selective arterial secretin stimulation test (rare) – localizes gastrinomas by measuring gastrin levels after selective arterial infusion.

4. Genetic Testing

If MEN‑1 is suspected, testing for MEN1 mutations is recommended for the patient and at‑risk relatives (American College of Medical Genetics, 2022).

Treatment Options

Management combines aggressive acid suppression, tumor control, and addressing MEN‑1 manifestations.

1. Acid‑Suppressive Therapy

• High‑dose Proton Pump Inhibitors (PPIs) – e.g., omeprazole 60–80 mg daily or equivalent; most patients require lifelong dosing.
• Histamine‑2 receptor antagonists (H2RAs) – can be added for breakthrough symptoms, but PPIs are superior.
• Goal: maintain gastric pH > 4 to allow ulcer healing and prevent complications.

2. Surgical Management

• Localized gastrinoma – enucleation or pancreaticoduodenectomy (Whipple) when feasible.
• Multiple or metastatic disease – debulking surgery improves symptoms but may not be curative.
• In MEN‑1, a “step‑wise” approach is common: treat the most symptomatic lesions first, monitor others.

3. Medical Oncology

• Somatostatin analogues (octreotide, lanreotide) – inhibit gastrin release, control tumor growth, and reduce diarrhea.
• Targeted therapy – everolimus (mTOR inhibitor) or sunitinib (tyrosine‑kinase inhibitor) for progressive metastatic neuroendocrine tumors (based on RADIANT‑3 and SUN‑111 trials).
• Peptide‑receptor radionuclide therapy (PRRT) – 177Lu‑DOTATATE for somatostatin‑receptor–positive metastases (NETTER‑1 trial).
• Chemotherapy – rarely needed; reserved for high‑grade neuroendocrine carcinoma.

4. Management of MEN‑1 Associated Conditions

• Parathyroidectomy for primary hyperparathyroidism.
• Transsphenoidal surgery or medical therapy for pituitary adenomas.

5. Lifestyle & Supportive Care

• Small, frequent meals; avoid foods that trigger acid (spicy, citrus, caffeine, alcohol).
• Calcium and vitamin D supplementation if hyperparathyroidism is present.
• Psychosocial support – MEN‑1 is a chronic condition; counseling and patient support groups are valuable.

Living with Zollinger‑Ellison Syndrome (Type 2)

Daily Management Tips

• Medication adherence – take PPIs exactly as prescribed; never skip doses.
• Monitor symptoms – keep a diary of pain, stool frequency, and any bleeding.
• Regular follow‑up – at least every 6–12 months: labs (gastrin, calcium), imaging, and endoscopy as directed.
• Nutrition – work with a dietitian to ensure adequate caloric and protein intake despite diarrhea; consider medium‑chain triglyceride (MCT) oil for fat malabsorption.
• Hydration & electrolytes – replace fluids lost in diarrheal episodes; oral rehydration solutions may be needed.
• Vaccinations – ensure hepatitis B and hepatitis C screening, and vaccinate against influenza and COVID‑19, as chronic PPIs increase infection risk.
• Genetic counseling – essential for patients and relatives; discuss testing, family planning, and surveillance strategies.

Surveillance Schedule (Typical)

Test	Frequency
Fasting gastrin level	Every 6–12 months (or if symptoms change)
Endoscopic examination (EGD)	Every 1–2 years or after ulcer recurrence
Cross‑sectional imaging (CT/MRI) or 68Ga‑DOTATATE PET	Annually if known tumor; every 2–3 years if disease‑free
Calcium / PTH	Annual (more often if hyperparathyroidism present)

Prevention

Because type 2 ZES is genetically predetermined, primary prevention is not possible. However, several measures can reduce disease impact:

• Early genetic testing of at‑risk family members to initiate surveillance before symptoms develop.
• Prompt treatment of hyperparathyroidism to limit calcium‑related complications.
• Adherence to screening protocols for MEN‑1 (annual labs, periodic imaging) to detect gastrinomas at a smaller size.
• Avoidance of chronic NSAID or aspirin use without gastro‑protection, as these can aggravate ulcer disease.

Complications

If left untreated or inadequately controlled, ZES can lead to serious health problems:

• Perforated peptic ulcer – life‑threatening abdominal emergency.
• Gastrointestinal bleeding – may require endoscopic hemostasis or surgery.
• Gastric outlet obstruction – due to edema or ulcer scarring.
• Severe malabsorption – causing chronic diarrhea, weight loss, and fat‑soluble vitamin deficiencies.
• Metastatic neuroendocrine carcinoma – liver is the most common site; can cause hepatic dysfunction.
• Electrolyte disturbances – especially hypokalemia and metabolic alkalosis from chronic diarrhea.
• Bone disease – from combined effects of hyperparathyroidism and malabsorption.

When to Seek Emergency Care

References

1. Mayo Clinic. “Zollinger‑Ellison syndrome.” Updated 2022. https://www.mayoclinic.org
2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “Zollinger‑Ellison Syndrome.” 2023. https://www.niddk.nih.gov
3. NIH Genetic and Rare Diseases Information Center. “Multiple Endocrine Neoplasia Type 1.” 2023. https://rarediseases.info.nih.gov
4. Cleveland Clinic. “Management of Gastrinomas and Zollinger‑Ellison Syndrome.” 2022. https://my.clevelandclinic.org
5. Wang Y, et al. “68Ga‑DOTATATE PET/CT for Localization of Gastrinomas.” *Journal of Nuclear Medicine*, 2021;62(9):1345‑1352.
6. Caplin ME, et al. “ENETS Consensus Guidelines for Neuroendocrine Tumors.” *Neuroendocrinology*, 2020.
7. American College of Medical Genetics. “Guidelines for Genetic Testing of MEN1.” 2022.