Zollinger‑Ellison Syndrome‑Associated Hyperparathyroidism: A Comprehensive Medical Guide

Overview

Zollinger‑Ellison syndrome (ZES) is a rare condition in which one or more gastrin‑producing tumors (gastrinomas) develop in the pancreas or duodenum, causing excessive gastric acid secretion. When ZES occurs in the setting of primary hyperparathyroidism (PHPT), it signals the hereditary disorder known as **MEN 1** (multiple endocrine neoplasia type 1). This combined presentation is sometimes described as “ZES‑associated hyperparathyroidism.”

• Who it affects: Primarily adults aged 30‑60, with a slight male predominance for ZES and a female predominance for PHPT.
• Prevalence: ZES occurs in ~1–3 per million people worldwide. Primary hyperparathyroidism affects about 1 % of the adult population, increasing with age. In MEN 1 families, up to 30 % develop ZES and 70 % develop PHPT, often simultaneously.
• Geography: No major regional differences; cases are reported globally.

Because the two disorders share a genetic basis, patients often present with overlapping gastrointestinal and metabolic symptoms, making a coordinated diagnostic approach essential.

Symptoms

Symptoms arise from two pathophysiologic mechanisms: (1) excessive gastric acid caused by gastrin‑secreting tumors, and (2) elevated calcium levels from overactive parathyroid glands.

Gastrinoma‑related (ZES) symptoms

• Peptic ulcer disease: Recurrent or multiple ulcers in the duodenum, jejunum, or stomach that are resistant to standard therapy.
• Abdominal pain: Often a burning or gnawing discomfort that worsens 1–2 hours after meals.
• Diarrhea or watery stools: Acid inactivates pancreatic enzymes, leading to malabsorption.
• Steatorrhea (fatty stools): Result of fat maldigestion; stools may float and have a foul odor.
• Nausea / vomiting: Especially after large meals.
• Weight loss: From chronic malabsorption.

Hyperparathyroidism‑related symptoms

• Hypercalcemia: Often the first laboratory clue; can cause nausea, constipation, and polyuria.
• Kidney stones (nephrolithiasis): Calcium oxalate stones from persistent hypercalcemia.
• Bone pain & fractures: Increased bone resorption leads to osteoporosis or osteitis fibrosa cystica.
• Neuropsychiatric manifestations: Fatigue, depression, confusion, or “brain fog.”
• Muscle weakness: Especially proximal muscles.
• Cardiac arrhythmias: Rare but possible with very high calcium levels.

Combined presentation

Patients with both conditions may notice a “double‑hit” of symptoms: severe ulcer disease that does not heal, coupled with early‑onset kidney stones or bone loss. The coexistence should raise suspicion for MEN 1, especially if there is a family history of endocrine tumors.

Causes and Risk Factors

Genetic basis

MEN 1 is an autosomal‑dominant syndrome caused by mutations in the MEN1 tumor suppressor gene, which encodes the protein menin. Loss of menin function predisposes to tumors in:

• Parathyroid glands (≈90 % of MEN 1 patients)
• Pancreatic duodenal endocrine cells, including gastrinomas (≈20‑30 %)
• Pituitary gland (≈30‑40 %)

Non‑genetic (sporadic) ZES

About 25 % of ZES cases are sporadic, not linked to MEN 1. In these patients, somatic mutations in MEN1 or CDKN1B may still be present, but the risk of hyperparathyroidism is much lower.

Risk factors

• Family history: A first‑degree relative with MEN 1 or any endocrine tumor dramatically raises risk.
• Age: MEN 1 manifestations typically appear between the third and fifth decades.
• Sex: Hyperparathyroidism is slightly more common in women; ZES shows a modest male bias.
• Radiation exposure: No strong evidence linking radiation to MEN 1, but prior abdominal radiation can increase pancreatic tumor risk.

Diagnosis

Because the two conditions influence each other, a systematic work‑up that includes both gastrointestinal and endocrine evaluation is recommended.

Initial laboratory evaluation

1. Serum gastrin level: Fasting gastrin >1000 pg/mL (with gastric pH < 2) is highly suggestive of ZES (sensitivity ≈ 90 %).
2. Serum calcium and ionized calcium: Total calcium >10.5 mg/dL (2.65 mmol/L) or ionized calcium >1.30 mmol/L warrants further work‑up for PHPT.
3. Parathyroid hormone (PTH): Inappropriately normal or elevated PTH in the setting of hypercalcemia confirms primary hyperparathyroidism.
4. 24‑hour urinary calcium: Helps differentiate PHPT from familial hypocalciuric hypercalcemia.
5. Additional labs: Serum magnesium, phosphate, vitamin D, and renal function.

Imaging studies

• Upper endoscopy (EGD): Visualizes ulcers, especially in the jejunum where ZES ulcers are common.
• Somatostatin receptor scintigraphy (Octreoscan) or ^68Ga‑DOTATATE PET/CT: Sensitive for locating gastrinomas (detects >90 % of lesions >5 mm).
• Endoscopic ultrasound (EUS): Provides high‑resolution images of pancreatic head lesions and can guide fine‑needle aspiration.
• Neck ultrasound or 4‑D CT: First‑line for localizing hyperfunctioning parathyroid glands.
• Dual‑phase sestamibi scan: Highlights over‑active parathyroid tissue; concordance with ultrasound improves surgical planning.

Genetic testing

If MEN 1 is suspected, sequence analysis of the MEN1 gene (and, if negative, multiplex ligation‑dependent probe amplification for large deletions) is recommended. Testing enables cascade screening for family members.

Diagnostic criteria summary

• Fasting gastrin >1000 pg/mL + gastric acidity (pH < 2) → ZES.
• Hypercalcemia + elevated/inappropriate PTH → Primary hyperparathyroidism.
• Presence of a pathogenic MEN1 mutation → MEN 1; otherwise, classify as sporadic ZES or isolated PHPT.

Treatment Options

Treatment aims to control acid hypersecretion, manage hypercalcemia, and remove or reduce tumor burden while preserving quality of life.

Medical management of ZES

• Proton pump inhibitors (PPIs): High‑dose omeprazole 40‑80 mg daily (or equivalent) is first‑line; most patients achieve >90 % ulcer healing.
• H2‑receptor antagonists: Used if PPIs are contraindicated, though less effective.
• Somatostatin analogues (e.g., octreotide, lanreotide): Reduce gastrin secretion, useful in unresectable or metastatic disease.
• Hydrochloric acid‑binding agents: Aluminum hydroxide may be added for breakthrough symptoms.

Surgical management of gastrinomas

• Curative resection: Enucleation or pancreaticoduodenectomy for localized tumors; 5‑year disease‑free survival >70 % when complete removal is achieved.
• Debulking surgery: For metastatic disease, reduces tumor load and improves symptom control.
• Locoregional therapies: Radiofrequency ablation or trans‑arterial embolization for liver metastases.

Management of primary hyperparathyroidism

• Parathyroidectomy: Minimally invasive focused surgery is the definitive cure; >95 % cure rate in MEN 1 when four‑gland exploration is performed.
• Calcimimetics (cinacalcet): Lower calcium in patients who are not surgical candidates.
• Bisphosphonates or denosumab: Treat bone loss while awaiting surgery.

Lifestyle & supportive measures

• Maintain a low‑acid diet (avoid coffee, alcohol, spicy foods) while on medical therapy.
• Limit calcium‑rich foods (dairy, fortified juices) if hypercalcemia is severe; however, do not restrict calcium too aggressively without professional guidance.
• Stay well‑hydrated (2‑3 L/day) to reduce kidney‑stone risk.
• Stop smoking and limit NSAIDs, which exacerbate ulcer disease.
• Regular exercise to preserve bone density.

Living with Zollinger‑Ellison Syndrome‑Associated Hyperparathyroidism

Monitoring schedule

• Every 6 months: Serum calcium, PTH, gastrin, and fasting gastric pH.
• Annually: Bone density (DEXA) and renal ultrasound for stones.
• Post‑surgery: Check calcium and PTH within 24‑48 hours, then at 1 month and 6 months.

Medication adherence

PPIs must be taken consistently; missed doses quickly raise gastric acidity and can precipitate ulcer bleeding. Use pill organizers or smartphone reminders.

Dietary tips

• Eat small, frequent meals to reduce acid peaks.
• Include lean protein and complex carbs; avoid high‑fat meals that delay gastric emptying.
• Use calcium citrate (not carbonate) if supplementation is needed, as it is absorbed independent of stomach acidity.

Psychosocial support

Chronic disease can cause anxiety and depression. Referral to a counselor, support groups (e.g., MEN 1 Foundation), or a mental‑health professional is advisable.

Family planning

MEN 1 is inheritable; genetic counseling is recommended before conception. Prenatal testing or pre‑implantation genetic diagnosis (PGD) are options for families who wish to avoid transmission.

Prevention

Because the core problem is a genetic mutation, primary prevention is not possible. However, secondary prevention—reducing complications—focuses on early detection and lifestyle measures.

• Screen at‑risk relatives: Annual calcium, PTH, and gastrin checks starting at age 10–15 for confirmed MEN 1 families.
• Maintain bone health: Vitamin D sufficiency (≥30 ng/mL), weight‑bearing exercise, and avoid smoking.
• Limit ulcer‑promoting agents: Use NSAIDs only when necessary and with gastro‑protective co‑therapy.

Complications

If left untreated, the combination of ZES and hyperparathyroidism dramatically raises morbidity.

• Refractory peptic ulcer disease: Can lead to perforation, hemorrhage, and peritonitis.
• Severe hypercalcemia (>14 mg/dL): Causes neurocognitive changes, cardiac arrhythmias, and renal failure.
• Nephrolithiasis & chronic kidney disease: Repeated stones and hypercalciuria damage renal parenchyma.
• Osteoporosis / pathologic fractures: Up to 50 % of MEN 1 patients develop significant bone loss.
• Metastatic gastrinoma: Occurs in 20‑30 % of sporadic ZES; liver is the most common site.
• Pancreatitis: From tumor invasion or obstruction.

When to Seek Emergency Care

Key Takeaways

• Zollinger‑Ellison syndrome associated with hyperparathyroidism most often signals MEN 1, a hereditary endocrine tumor syndrome.
• The twin triad of refractory ulcers, hypercalcemia, and a family history should prompt combined gastro‑endocrine work‑up.
• High‑dose PPIs control acid; surgery (parathyroidectomy + gastrinoma resection) offers cure in many cases.
• Lifelong monitoring, calcium‑aware diet, and regular bone health assessments are essential to prevent complications.
• Genetic counseling and testing protect future generations and guide screening of relatives.

For personalized advice, always discuss findings and treatment plans with an endocrinologist, gastroenterologist, and, when surgery is considered, a high‑volume pancreatic‑biliary surgeon.

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Sources: Mayo Clinic, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), American College of Gastroenterology guidelines, Cleveland Clinic, National Cancer Institute, World Health Organization, MEN 1 Foundation Clinical Guidelines (2023).