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Zollinger‑Ellison‑like Syndrome: A Patient‑Centered Guide

Overview

Zollinger‑Ellison‑like syndrome (ZEL‑like syndrome) describes a group of rare conditions that mimic the classic features of Zollinger‑Ellison syndrome (ZES) – namely, excessive gastric acid production caused by gastrin‑secreting tumors (gastrinomas) or by other mechanisms that lead to similar clinical pictures. Unlike classic ZES, which is almost always due to a single or multiple gastrin‑secreting neuroendocrine tumors, ZEL‑like syndrome may arise from:

• Non‑neoplastic hypergastrinemia (e.g., chronic proton‑pump inhibitor use, renal failure)
• Other neuroendocrine tumors that produce gastrin indirectly
• Hormone‑producing pancreatic or duodenal tumors that are not classified as true gastrinomas

Because the underlying cause differs, the term “Zollinger‑Ellison‑like” is used by clinicians to signal identical symptomatology but a distinct etiology.

Who it affects: ZEL‑like syndrome is extremely rare. Classic ZES occurs in roughly 0.1–1 case per million people annually, and the “like” variant is estimated to represent <1% of those cases. It can appear at any age but most patients are diagnosed between 30 and 60 years old. Both sexes are affected equally, though certain underlying causes (e.g., chronic kidney disease) are more common in older adults.

Prevalence: Precise prevalence is unknown because the condition is often grouped under ZES or general hypergastrinemia. Current estimates suggest fewer than 100 documented cases worldwide, based on case‑series published in gastroenterology journals.

Symptoms

Symptoms stem from the high levels of gastric acid that damage the lining of the stomach and duodenum and from the tumor‑related effects when a neoplasm is present.

Gastrointestinal (GI) symptoms

• Recurrent peptic ulcers – often multiple, large, or located beyond the duodenum (e.g., jejunal ulcers).
• Abdominal pain – typically burning or gnawing, worsens 1–2 hours after meals.
• Diarrhea – excess acid inactivates pancreatic enzymes and damages the intestinal mucosa, leading to watery stools; may be steatorrhea (fatty stools) if malabsorption develops.
• Heartburn / GERD – acid reflux due to high gastric acid output.
• Nausea & vomiting – occasionally with bile if the obstruction is distal.

Systemic symptoms

• Weight loss – secondary to malabsorption, chronic diarrhea, and reduced appetite.
• Fatigue – from anemia (iron deficiency or chronic disease) and nutrient deficiencies.
• Glossitis & mouth ulcers – acid irritation of the oral mucosa.
• Osteoporosis – long‑term acid excess can impair calcium absorption.

Signs that suggest an underlying tumor (when present)

• Palpable abdominal mass
• Unexplained hypoglycemia (if tumor secretes insulin‑like peptides)
• Skin changes (flushing, rash) – rare, may indicate a mixed neuroendocrine tumor

Causes and Risk Factors

Because ZEL‑like syndrome is a “syndrome” rather than a single disease, causes are heterogeneous.

Primary causes

1. Non‑neoplastic hypergastrinemia
   • Chronic proton‑pump inhibitor (PPI) therapy – long‑term suppression of acid leads to feedback‑driven gastrin rise.
   • Renal failure – impaired clearance of gastrin.
   • H. pylori infection – stimulates G‑cells, especially after eradication failure.
2. Neuroendocrine tumors (NETs) that are not classic gastrinomas
   • Pancreatic NETs producing mixed hormones.
   • Duodenal or gastric NETs that secrete gastrin indirectly.
3. Genetic syndromes
   • Multiple Endocrine Neoplasia type 1 (MEN1) – 20‑30 % of MEN1 patients develop gastrin‑producing tumors that can present as ZEL‑like.

Risk factors

• Long‑term use (>5 years) of high‑dose PPIs or H2‑blockers.
• Chronic kidney disease (stage 3‑5) or dialysis.
• Known neuroendocrine tumor history.
• Family history of MEN1 or other hereditary endocrine disorders.
• Persistent H. pylori infection despite treatment.

Diagnosis

Diagnosing ZEL‑like syndrome requires a systematic approach to confirm hypergastrinemia, assess acid output, and identify the underlying cause.

Step‑by‑step diagnostic pathway

1. Clinical evaluation – detailed history of ulcer disease, medication use, renal function, and family history.
2. Laboratory tests
   • Serum gastrin level – fasting level > 100 pg/mL is abnormal; levels often exceed 1,000 pg/mL in true gastrinomas, but can be modestly elevated in non‑neoplastic states.
   • Secretin stimulation test – gastrin rises > 120 pg/mL after IV secretin in gastrinomas; a blunted or absent response suggests non‑neoplastic hypergastrinemia.
   • Basic metabolic panel – assesses renal function (creatinine, eGFR).
   • Iron studies, vitamin B12, and calcium – to detect deficiencies caused by chronic acid loss.
3. Imaging studies
   • Upper endoscopy (EGD) – visualizes ulcers, obtains biopsies for H. pylori, and rules out malignancy.
   • Somatostatin receptor scintigraphy (Octreoscan) or Ga‑68 DOTATATE PET/CT – most sensitive for locating gastrin‑producing NETs.
   • CT or MRI of abdomen/pelvis – to detect pancreatic or duodenal masses.
4. Additional tests when needed
   • 24‑hour gastric pH monitoring – confirms acid hypersecretion (pH < 2 for > 60 % of the day).
   • Bone densitometry – if osteoporosis is suspected.

Diagnosis is confirmed when:

• Fasting gastrin is elevated beyond the normal range,
• Acid output is demonstrably high, and
• An underlying cause (tumor, renal failure, medication) is identified.

Treatment Options

Therapy is tailored to the identified cause and the severity of acid‑related complications.

1. Acid suppression (first‑line for most patients)

• Proton‑pump inhibitors (PPIs) – omeprazole, esomeprazole, pantoprazole, or high‑dose IV esomeprazole in acute settings. Doses may be 2–4× standard because gastrinomas produce massive acid.
• Histamine‑2 receptor antagonists (H2‑blockers) – often added for breakthrough symptoms, but less effective than PPIs.

2. Treatment of the underlying cause

• Neuroendocrine tumor resection – surgical removal (enucleation, distal pancreatectomy, or duodenectomy) is curative when feasible.
• Somatostatin analogs – octreotide or lanreotide reduce gastrin release and are first‑line for unresectable or metastatic NETs.
• Targeted therapies – everolimus or sunitinib for progressive pancreatic NETs.
• Renal replacement therapy optimization – for patients with chronic kidney disease, adjusting dialysis or managing renal function can lower gastrin levels.
• Discontinuation or tapering of PPIs – if drug‑induced hypergastrinemia is suspected, a supervised taper is essential to avoid rebound acid hypersecretion.

3. Supportive and lifestyle measures

• Small, frequent meals low in fat and acid‑stimulating foods (caffeine, alcohol, spicy foods).
• Calcium and vitamin D supplementation if bone loss is present.
• Iron supplementation for anemia.
• Probiotic or soluble fiber to help control diarrhea.

4. Monitoring

After initiating therapy, most clinicians repeat fasting gastrin and acid‑output tests every 6–12 months and obtain imaging annually for tumor surveillance.

Living with Zollinger‑Ellison‑like Syndrome

Long‑term management focuses on controlling acid, maintaining nutrition, and monitoring for tumor recurrence.

Daily management checklist

1. Take PPIs exactly as prescribed – usually 30 minutes before breakfast; do not skip doses.
2. Track symptoms – use a simple diary for pain, stool frequency, and any new ulcers.
3. Stay hydrated – especially if diarrhea is common; oral rehydration solutions can replace lost electrolytes.
4. Eat a balanced diet
   • Prefer lean proteins, whole grains, and non‑acidic fruits (e.g., bananas, melons).
   • Avoid trigger foods: citrus, tomato‑based sauces, coffee, and chocolate.
5. Supplement wisely – calcium citrate (better absorbed in low‑acid environment) and vitamin D 800–1000 IU daily, unless contraindicated.
6. Regular follow‑up – keep appointments with gastroenterology and endocrinology.
7. Medication review – discuss any new drugs with your doctor; some NSAIDs or steroids can worsen ulcer disease.
8. Stress management – chronic illness can affect mental health; consider counseling, mindfulness, or support groups.

Travel and social life

• Carry a spare PPI dose and a copy of your prescription.
• When eating out, request “no added citrus or tomato sauce” and ask for grilled instead of fried foods.
• Stay near medical facilities if you have a known tumor that may cause complications.

Prevention

Because many cases arise secondary to other conditions, prevention focuses on risk‑factor modification.

• Use PPIs only when medically indicated – avoid chronic over‑the‑counter use; discuss step‑down strategies with your physician.
• Manage chronic kidney disease – adhere to nephrology recommendations, control blood pressure, and limit nephrotoxic drugs.
• Eradicate Helicobacter pylori – testing and appropriate antibiotic therapy reduce gastrin stimulation.
• Screen high‑risk families – relatives of patients with MEN1 may benefit from periodic gastrin testing and imaging.
• Maintain a healthy weight – obesity can exacerbate GERD and increase the need for acid‑suppressive medication.

Complications

If untreated or inadequately controlled, ZEL‑like syndrome can lead to serious health issues.

• Refractory peptic ulcer disease – may cause bleeding, perforation, or obstruction.
• Upper gastrointestinal bleeding – presents as melena or hematemesis; can be life‑threatening.
• Gastric outlet obstruction – from severe ulcer scarring.
• Malabsorption and nutritional deficiencies – iron, calcium, Vitamin B12, leading to anemia, osteoporosis, neuropathy.
• Metastatic NET spread – liver or lymph node involvement worsens prognosis.
• Renal stones – chronic acid load can increase urinary calcium excretion.
• Reduced quality of life – chronic pain, diarrhea, and anxiety about ulcer recurrence.

When to Seek Emergency Care

References

• Mayo Clinic. Zollinger‑Ellison Syndrome. https://www.mayoclinic.org/diseases‑conditions/zollinger‑ellison-syndrome/diagnosis‑treatment/.
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “Gastrinomas and Zollinger‑Ellison Syndrome.” https://www.niddk.nih.gov/health-information/digestive-diseases/zollinger‑ellison‑syndrome.
• American College of Gastroenterology. “Management of Gastric Acid Hypersecretion.” Gastroenterology 2022;162(5):1473‑1485.
• Cleveland Clinic. “Neuroendocrine Tumors of the Pancreas and Duodenum.” https://my.clevelandclinic.org/health/diseases/21073-neuroendocrine‑tumors.
• World Health Organization (WHO). “Classification of Digestive System Tumours.” 5th Ed., 2019.
• J. Locasciulli et al. “Non‑neoplastic Hypergastrinemia after Long‑Term PPI Use.” *Gut* 2021;70(8):1442‑1449.

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