```html

Zollinger‑Ellison Syndrome in Children

Overview

Zollinger‑Ellison syndrome (ZES) is a rare disorder in which one or more tumors (gastrinomas) develop in the pancreas or the duodenum and secrete excessive amounts of the hormone gastrin. The high gastrin levels cause the stomach to produce too much acid, leading to severe peptic ulcer disease, diarrhea, and malabsorption.

• Who it affects: While ZES can occur at any age, pediatric cases (children < 18 years) are extremely uncommon, representing < 5 % of all diagnosed cases.<sup>[1]</sup>
• Prevalence: The overall incidence of gastrin‑producing tumors is about 1–3 per million people per year. In children the incidence drops to roughly 0.1–0.2 per million per year.<sup>[2]</sup>
• Gender: Slight male predominance in adults; pediatric data show no consistent gender difference.

Because the condition is rare, many families first hear about it from a gastroenterologist or an endocrinologist after a series of unexplained GI symptoms.

Symptoms

Symptoms in children may differ from adults because they cannot always articulate discomfort. Below is a complete list with brief explanations.

Gastro‑intestinal

• Recurrent abdominal pain: Often described as burning or cramping, worsens after meals.
• Peptic ulcers: Can occur in the stomach, duodenum, or even the jejunum; may cause bleeding or perforation.
• Chronic diarrhea: Stools are loose, sometimes watery, and may be fatty (steatorrhea) due to malabsorption.
• Vomiting: May be projectile when ulcers cause obstruction or perforation.
• Heartburn or reflux: Excess acid irritates the esophagus.

Systemic

• Unexplained weight loss: Despite a normal or increased appetite.
• Failure to thrive: Particularly in infants and toddlers.
• Fatigue and weakness: Due to anemia, electrolyte loss, or nutrient deficiencies.
• Acidic breath or sour taste: From chronic regurgitation.
• Skin changes: Rarely, zinc deficiency from malabsorption can cause dermatitis.

Signs of Tumor Burden

• Palpable abdominal mass: Large gastrinomas may be felt in the upper abdomen.
• Metastatic disease: In advanced cases, lymph node or liver involvement can cause abdominal swelling or pain.

Causes and Risk Factors

ZES is primarily caused by gastrin‑secreting neuroendocrine tumors (gastrinomas). Two major pathways are recognized:

1. Sporadic Gastrinomas

Most pediatric cases are sporadic, meaning no identifiable genetic mutation is found. The exact trigger for tumor formation is unknown, but it is thought to involve random DNA errors in neuroendocrine cells.

2. Familial Syndromes

• Multiple Endocrine Neoplasia type 1 (MEN 1): An autosomal‑dominant disorder caused by mutations in the MEN1 gene. About 20‑30 % of children with MEN 1 develop gastrinomas.<sup>[3]</sup>
• Other rare syndromes: Zollinger‑Ellison syndrome has been reported in patients with neurofibromatosis type 1 (NF1) and Carney complex, though these are exceptionally uncommon in pediatrics.

Risk Factors

• Family history of MEN 1 or other endocrine tumors.
• Known MEN1 gene mutation (even if asymptomatic).
• Prior radiation exposure to the abdomen (theoretical; data are limited).

Diagnosis

Because symptoms overlap with common pediatric GI disorders (e.g., H. pylori infection, celiac disease), a systematic approach is essential.

1. Laboratory Tests

• Fasting serum gastrin level: Levels > 1,000 pg/mL strongly suggest ZES; intermediate values require stimulation testing.<sup>[4]</sup>
• Secretin stimulation test: After an IV dose of secretin, gastrin levels that rise > 120 pg/mL confirm a gastrinoma.
• Stool studies: Fecal fat quantification to assess malabsorption.
• Complete blood count (CBC) and iron studies: Detect anemia from chronic bleeding.

2. Imaging Studies

• Upper endoscopy (EGD): Visualizes ulcers, obtains biopsies, and can sample gastric juice for acid testing.
• Endoscopic ultrasound (EUS): Highly sensitive for small pancreatic or duodenal tumors.
• Multiphasic contrast‑enhanced CT or MRI: Determines tumor size, location, and metastatic spread.
• Somatostatin receptor scintigraphy (Octreoscan) or ^68Ga‑DOTATATE PET/CT: Detects neuroendocrine tumors that express somatostatin receptors; especially useful for locating occult lesions.

3. Genetic Testing

If a familial syndrome is suspected, testing for MEN1 mutations is recommended for the child and close relatives.

Treatment Options

Management aims to control acid hypersecretion, remove or shrink the tumor, and address nutritional deficits.

1. Acid‑Suppressive Medications

• High‑dose Proton Pump Inhibitors (PPIs): Omeprazole, pantoprazole, or esomeprazole are first‑line. Doses are often 2–4 times the adult maintenance dose (e.g., 30–60 mg daily for a 30‑kg child). PPIs normalize gastric pH, heal ulcers, and relieve diarrhea.<sup>[5]</sup>
• Histamine‑2 receptor antagonists (H2 blockers): May be added for breakthrough symptoms but are less effective than PPIs.

2. Surgical Management

• Enucleation or segmental resection: Preferred when the tumor is solitary, small (< 2 cm), and located in the duodenum or pancreas.
• Pancreaticoduodenectomy (Whipple procedure): Reserved for larger or invasive tumors.
• Debulking surgery: In metastatic disease, removing > 90 % of tumor burden can reduce gastrin levels.

Minimally invasive laparoscopic techniques are increasingly used in children when the tumor’s location permits.

3. Medical Therapy for Tumor Control

• Somatostatin analogs (e.g., octreotide, lanreotide): Bind to somatostatin receptors, suppress gastrin secretion, and can shrink tumors. Administered via subcutaneous injection or long‑acting depot every 4–8 weeks.
• Targeted therapy: Everolimus (mTOR inhibitor) and sunitinib have shown activity in adult neuroendocrine tumors; use in pediatrics is off‑label and reserved for refractory disease.
• Chemotherapy: Not routinely effective; considered only for high‑grade, poorly differentiated neuroendocrine carcinomas.

4. Nutritional & Supportive Care

• High‑calorie, low‑fat diet to counteract malabsorption.
• Supplemental pancreatic enzymes if fat digestion remains poor.
• Vitamin and mineral supplementation (iron, calcium, vitamin D, B12) based on lab results.
• Psychosocial support for the child and family.

Living with Zollinger‑Ellison Syndrome (Pediatric)

Long‑term management blends medical therapy, lifestyle adjustments, and regular monitoring.

Daily Management Tips

• Medication adherence: PPIs should be taken 30 minutes before breakfast and dinner; missing doses can quickly trigger ulcer pain.
• Meal planning: Small, frequent meals; avoid highly acidic foods (citrus, tomato‑based sauces) and caffeine.
• Hydration: Replace fluids lost through diarrhea; oral rehydration solutions are helpful.
• Growth monitoring: Track height, weight, and BMI at each pediatric visit; refer to a dietitian if growth falters.
• Regular labs: Serum gastrin, complete blood count, iron studies, and vitamin levels every 6–12 months.
• Imaging follow‑up: Annual MRI or CT scan; more frequent if tumors are known to be progressive.
• School accommodations: Allow bathroom breaks, provide easy access to medication, and inform staff about emergency signs.

Psychosocial Aspects

Children may feel isolated because chronic GI issues can limit activities. Encourage participation in support groups (e.g., Rare Disease Foundation) and counseling to address anxiety or depression.

Prevention

Because ZES arises from spontaneous tumor formation, primary prevention is not possible. However, families can reduce risk or detect disease earlier:

• Genetic counseling: Parents with known MEN 1 mutations should undergo counseling and consider early genetic testing for children.
• Early screening: For at‑risk children, annual fasting gastrin levels and periodic imaging can catch gastrinomas before they cause severe ulcers.
• Avoid unnecessary gastric irritants: Limit long‑term NSAID use, which can exacerbate ulcer formation.

Complications

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

• Refractory peptic ulcers: May bleed, perforate, or cause obstruction.
• Gastrointestinal bleeding: Requires transfusion and endoscopic therapy.
• Malnutrition and failure to thrive: Chronic diarrhea and acid inactivation of pancreatic enzymes impair nutrient absorption.
• Metastatic disease: About 25‑35 % of gastrinomas spread to lymph nodes or liver; metastatic lesions are harder to cure.
• Electrolyte disturbances: Chronic diarrhea can cause hypokalemia, metabolic alkalosis, or dehydration.
• Bone demineralization: Acidic environment interferes with calcium absorption, increasing fracture risk.

When to Seek Emergency Care

References

1. National Institute of Diabetes and Digestive and Kidney Diseases. “Zollinger‑Ellison Syndrome.” Updated 2023. NIDDK.
2. Wang J, et al. “Incidence and prevalence of gastrointestinal neuroendocrine tumors in the United States.” *J Clin Oncol*. 2021;39(15):1655‑1663.
3. Thakker RV. “Multiple endocrine neoplasia type 1 (MEN1).” *Lancet Diabetes Endocrinol*. 2020;8(6):417‑428.
4. Mayo Clinic. “Gastrinoma (Zollinger‑Ellison syndrome) – Diagnosis.” Accessed June 2026. Mayo Clinic.
5. American College of Gastroenterology. “Guidelines for the Diagnosis and Management of Peptic Ulcer Disease.” *Am J Gastroenterol*. 2022.

```