Zollinger-Ellison syndrome

Zollinger-Ellison Syndrome (ZES) is a rare disorder characterized by the formation of one or more gastrin-secreting tumors, known as gastrinomas, in the pancreas and the upper part of the small intestine (duodenum). These tumors lead to excessive production of gastrin, a hormone that stimulates the production of gastric acid by the stomach. As a result, patients with Zollinger-Ellison Syndrome experience severe peptic ulcers, gastroesophageal reflux disease (GERD), and can have complications arising from the excessive acid production.

Causes

The primary cause of Zollinger-Ellison Syndrome is the presence of gastrinomas. The majority of these tumors are sporadic, but about 25-30% of cases are associated with an inherited syndrome called Multiple Endocrine Neoplasia type 1 (MEN1). MEN1 is a genetic disorder that affects multiple endocrine glands, leading to the development of tumors or overactivity in those glands.

Symptoms

Symptoms of Zollinger-Ellison Syndrome can include:

• Severe peptic ulcer disease
• Diarrhea
• Gastroesophageal reflux disease (GERD)
• Abdominal pain
• Nausea and vomiting
• Weight loss
• Bleeding in the digestive tract

Diagnosis

Diagnosis of Zollinger-Ellison Syndrome involves a combination of clinical evaluation, laboratory tests, and imaging studies. Key diagnostic steps include:

• Measurement of fasting serum gastrin levels, which are typically elevated in ZES.
• Secretin stimulation test, which can further confirm the diagnosis by demonstrating an exaggerated increase in gastrin levels upon administration of secretin.
• Imaging studies such as endoscopic ultrasound, computed tomography (CT) scans, and magnetic resonance imaging (MRI) to locate the gastrinomas.
• Somatostatin receptor scintigraphy (SRS) can also be used to detect gastrin-secreting tumors.

Treatment

Treatment options for Zollinger-Ellison Syndrome aim to control symptoms and may include:

• Proton pump inhibitors (PPIs) to reduce gastric acid production.
• Surgical removal of gastrinomas, when possible, is the only curative treatment.
• Treatment for associated conditions, such as MEN1, if present.
• In cases where tumors have metastasized, treatment may involve chemotherapy or targeted therapies.

Prognosis

The prognosis for patients with Zollinger-Ellison Syndrome varies depending on the presence of metastatic disease and the ability to successfully remove the tumors surgically. With effective management of gastric acid hypersecretion, many patients can achieve good quality of life.

Epidemiology

Zollinger-Ellison Syndrome is a rare condition, with an estimated incidence of 1 to 3 cases per million people per year. It can occur at any age but is most commonly diagnosed in adults between the ages of 30 and 50.