Makindo Medical Notes

🧪 A gastrinoma is a rare, gastrin-secreting tumour that causes excessive gastric acid production, often leading to recurrent and severe peptic ulcer disease. It is the main cause of Zollinger–Ellison syndrome (ZES). 🔥

📖 About

• 🧬 Neuroendocrine tumour secreting excess gastrin, stimulating gastric acid hypersecretion → peptic ulcers.
• 📍 Usually arises in the pancreas or duodenum within the “gastrinoma triangle.”
• 🎗️ Main cause of Zollinger–Ellison syndrome.

🧬 Aetiology

• Most cases are sporadic, but ~25% linked to Multiple Endocrine Neoplasia type 1 (MEN-1).
• Excessive gastrin → uncontrolled gastric acid → recurrent, multiple, or refractory peptic ulcers.

🩺 Clinical Features

• ⚡ Severe/recurrent peptic ulcer disease (90%).
• 🤕 Abdominal pain and refractory dyspepsia.
• 💩 Diarrhoea and steatorrhoea due to acid inactivation of pancreatic enzymes.
• ⚠️ Complications: bleeding, perforation, gastric outlet obstruction.

🔬 Investigations

• 📈 Serum gastrin: >1000 pg/mL with high acid output strongly suggests gastrinoma.
• 💉 Secretin stimulation test: paradoxical rise in gastrin confirms diagnosis.
• 📹 EUS, CT/MRI, and Octreoscan to localise tumour and assess metastases.
• 🧬 MEN-1 screening: parathyroid & pituitary assessment + genetic testing.

⚕️ Management

• 💊 PPIs (high-dose): cornerstone of therapy to control acid hypersecretion.
• 💊 Somatostatin analogues (octreotide) for symptom and tumour control in advanced cases.
• ✂️ Surgical resection: potentially curative in localised disease.
• 🧪 Targeted therapy (e.g., sunitinib, everolimus) or chemotherapy for metastatic disease.
• 🩻 Vagotomy rarely considered if refractory acid production persists.

📊 Prognosis

• 📍 Localised tumours = favourable prognosis with surgery.
• 🩸 Metastatic disease (esp. liver) → poorer outcomes, but acid control with PPIs improves quality of life.

📚 Cases — Gastrinoma

• Case 1 (Sporadic ZES): 👨‍⚕️ A 42-year-old man has multiple duodenal ulcers resistant to high-dose PPIs, plus chronic diarrhoea. Serum gastrin 1850 pg/mL; secretin test positive. CT shows a 2 cm duodenal mass. Management: Surgical resection of tumour + ongoing PPI. Outcome: Symptoms resolve; no recurrence at 3-year follow-up.
• Case 2 (MEN-1 associated): 👩 A 36-year-old woman with family history of pituitary adenoma presents with recurrent peptic ulcer disease and steatorrhoea. Serum gastrin 2100 pg/mL; Octreoscan shows pancreatic tail lesion + parathyroid hyperplasia. Management: MEN-1 workup; subtotal parathyroidectomy, high-dose PPI, and octreotide. Tumour surgically debulked but liver metastases found. Outcome: Good symptom control with PPIs + octreotide. Remains under oncology and endocrinology surveillance.

🧑‍⚕️ Teaching Commentary

Gastrinomas cause Zollinger–Ellison syndrome, classically presenting with multiple, recurrent, or refractory ulcers and diarrhoea. Always suspect in “ulcers out of proportion” to risk factors. 🔑 Key points: • Consider MEN-1 if young or with family history. • Diagnosis = high fasting gastrin + secretin test. • Treatment = PPIs to control acid, plus surgery if resectable. • Prognosis hinges on metastatic status. Early diagnosis is lifesaving. 🚑