saudigastro.com/patients/zollinger-ellison-syndrome
Category
Chronic
Red flags
5
This article is educational and does not replace your doctor's advice. Seek urgent care for any red-flag symptoms.
What is it?
In Zollinger-Ellison syndrome (ZES), a tumour called a gastrinoma produces too much of a hormone called gastrin. Gastrin tells the stomach to make acid, so the stomach produces far more acid than normal. The excess acid injures the lining of the stomach, the duodenum (first part of the small bowel) and sometimes the esophagus, leading to ulcers, reflux and diarrhea. Gastrinomas are a type of neuroendocrine tumour, usually small, and most often found in the duodenum or pancreas. Some are slow growing, but some can spread, so careful assessment is needed.
How common is it?
It is rare and is often missed or diagnosed late because its symptoms look like common ulcer or reflux disease. It should be suspected when ulcers are severe, come back, or are in unusual places, or when reflux with chronic diarrhea does not settle.
Why does it happen?
Most gastrinomas occur by chance. A minority are part of an inherited condition called multiple endocrine neoplasia type 1 (MEN1), which can affect the parathyroid glands, pituitary gland and pancreas. Your doctor may ask about your family history and check calcium levels and other hormones.
Symptoms
- Burning upper belly pain, like a peptic ulcer, that may be severe and persistent
- Heartburn and acid reflux
- Diarrhea, sometimes fatty, caused by too much acid in the bowel
- Nausea, vomiting and poor appetite
- Weight loss
- Bleeding from an ulcer, causing black stool or tiredness from anemia
Red flags — seek urgent medical care
Vomiting blood or black, tar-like stool
Bleeding ulcer. Go to the emergency department immediately.
Sudden severe belly pain with a rigid belly
Possible perforated ulcer. This is an emergency.
Repeated vomiting and inability to eat or drink
May mean scarring and blockage or dehydration. Seek urgent care.
Severe or watery diarrhea with dizziness or muscle cramps
Dehydration and salt loss. Needs urgent assessment.
Ulcers that keep returning despite treatment, or unintended weight loss
Tell your doctor; this may need tests for ZES or other causes.
How is it diagnosed?
Testing begins with a blood test for fasting gastrin level. Because many common medicines (especially acid-lowering medicines called proton pump inhibitors) raise gastrin, interpretation can be difficult. Your specialist may check stomach acid levels or perform a secretin stimulation test. Upper endoscopy shows ulcers and thickened folds. Imaging such as CT, MRI, endoscopic ultrasound and specialised scans are used to find the tumour and see whether it has spread. Do not stop acid-lowering medicine before testing unless your doctor tells you to, because stopping suddenly can be dangerous.
What the latest science says
Modern acid-suppressing medicines control symptoms and ulcers very well, so the main long-term concern is the tumour itself. Specialist teams now use advanced imaging to find small tumours and decide whether surgery can cure the disease. Treatment of tumours that have spread is individualised.
Outlook — what to expect
Acid control is usually very effective, and many people live with good symptom control. The long-term outlook depends on the tumour: whether it can be removed, whether it has spread, and whether MEN1 is present. Regular follow-up is important.
Treatment
Habits & Lifestyle
Taking acid control seriously and staying in regular follow-up protects you from complications.
- Take acid-lowering medicine exactly as prescribed; do not skip or stop it, as a rebound of acid can cause bleeding ulcers.
- Stop smoking, which worsens ulcers.
- Avoid NSAID painkillers unless your doctor agrees.
- Attend regular tests and scans to monitor the tumour.
- Tell family members about the diagnosis if MEN1 is suspected so they can be advised about screening.
Diet
Diet does not cure the condition, but eating well helps recovery from diarrhea and weight loss.
- Eat regular balanced meals with enough protein and calories.
- Limit foods or drinks that clearly make your symptoms worse.
- Drink enough fluids, especially if you have diarrhea.
- Long-term acid suppression can lower absorption of vitamin B12, iron, calcium and magnesium; ask your doctor about monitoring.
Medications
Medicines to control stomach acid are the backbone of treatment. Doses are often higher than usual and are set by your specialist.
- Proton pump inhibitors (PPIs) are the main medicines and usually control the acid and heal ulcers.
- Take your medicine at the times advised; your doctor may adjust it based on symptoms and tests.
- Medicines for the tumour itself (for example somatostatin-type injections or other cancer treatments) may be used if it has spread; the specialist team decides.
- Report side effects such as persistent diarrhea, bone pain or tingling.
Procedures & Surgery
If the tumour can be found and is in a place where it can be removed, surgery offers a chance of cure.
- Endoscopy and endoscopic ultrasound help find and sample the tumour.
- Surgery to remove the tumour is considered when suitable, often by experienced pancreatic or endocrine surgeons.
- Other procedures may be used for tumours that have spread to the liver.
- Endoscopy may treat bleeding ulcers when they occur.
Living with the condition
- Never stop acid-lowering medicine suddenly; carry a list of your medicines when travelling.
- Make sure all your doctors know the diagnosis.
- Support from your specialist team and family helps with the worry of a rare diagnosis.
Questions to ask your doctor
Save this list or print it before your appointment — doctors appreciate prepared patients.
- How certain is the diagnosis, and what further tests do I need?
- Where is the tumour and can it be removed?
- Do I need genetic testing or screening for MEN1?
- How long will I need acid-lowering medicine?
- What follow-up and scans will I need?
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Status: Approved for publication by SGA; individual clinician review is ongoing · Published 24/04/2026
For general education only; it does not replace your doctor’s advice. Individual clinician review of this guide is ongoing. SGA clinician? Review this guide