Recognizing Symptoms and Warning Signs of ZES

Zollinger-Ellison Syndrome (ZES) is defined by excess gastric-acid secretion. While a healthy stomach produces acid to digest food, the gastrinomas (tumors) in ZES force the stomach to produce abnormal amounts of acid constantly ^[1][2]. This excess acid overwhelms the natural defenses of your digestive tract, leading to the symptoms and complications described below.

Common Symptoms of Excess Acid

Because the body is producing more acid than it can handle, most patients experience symptoms that mimic severe “standard” digestive issues ^[3].

• Abdominal Pain: Roughly 90% of patients report pain in the upper abdomen (epigastric area) ^[1]. This pain is caused by peptic ulcers—open sores in the lining of the stomach or small intestine.
• Refractory Ulcers: Unlike typical ulcers, ZES ulcers often fail to heal after 8–12 weeks of standard treatment ^[4]. They may also appear in unusual locations, such as the second or third part of the small intestine (distal duodenum) ^[5].
• Chronic Diarrhea: About half of all patients experience watery diarrhea ^[1]. This happens because the extreme acidity in the small intestine interferes with how your body breaks down fats and absorbs water ^[6].
• Severe GERD: You may experience intense heartburn, acid regurgitation, or dysphagia (difficulty swallowing) ^[7]. Over time, constant acid exposure can scar the esophagus, leading to strictures (narrowing) that make it hard for food to pass ^[8].
• Unexplained Weight Loss: This often occurs due to a combination of persistent diarrhea and the body’s inability to properly absorb nutrients in a high-acid environment ^[9][10].

Recognizing a Medical Emergency

While ZES is a chronic condition, it can cause sudden, life-threatening complications. These require immediate emergency medical attention.

Signs of Gastrointestinal Bleeding

Acid can erode a blood vessel within an ulcer. Seek emergency care if you notice:

• Hematemesis: Vomiting bright red blood or material that looks like dark “coffee grounds” ^[11][8].
• Melena: Stools that are black, tarry, and have a very foul odor (this is digested blood) ^[11].
• Shock Symptoms: Feeling suddenly faint, dizzy, cold, or clammy, which may indicate internal blood loss ^[12].

Signs of Perforation

A perforation occurs when an ulcer eats completely through the wall of the stomach or intestine, allowing stomach contents to leak into the abdominal cavity ^[13]. This is a surgical emergency.

• Sudden, “Thunderclap” Pain: Intense, excruciating abdominal pain that starts abruptly ^[14].
• Rigid Abdomen: Your stomach muscles may feel hard or “board-like” to the touch ^[14].

Severe Dehydration and Kidney Risk

The watery diarrhea in ZES can be so voluminous that it leads to severe dehydration and Acute Kidney Injury (AKI) ^[11][10]. Even if acid is controlled, persistent diarrhea requires evaluation.

• Red Flags: Markedly reduced urine output (not urinating for many hours) or very dark, tea-colored urine ^[11][1]. New confusion, extreme lethargy, or fainting are also signs of severe dehydration ^[15].
• Action Plan: If you have severe diarrhea, use oral rehydration solutions (not just plain water) and contact your specialist the same day if you cannot keep fluids down.

How Symptoms Relate to Gastrin

All of these symptoms trace back to hypergastrinemia (excess gastrin in the blood). Gastrin is a powerful signal for the acid-producing cells in your stomach ^[1]. In ZES, the tumor continuously sends that signal. Because of this, symptoms can recur if your acid-blocking medication is interrupted ^[16][17].

If you miss a dose or vomit your medication: Follow the missed-dose directions given by your care team. Do not double doses on your own. If you are unable to keep the medication down, contact your specialist or go to the emergency room, as you may need an intravenous (IV) alternative to control the acid ^[3].