Zollinger Ellison syndrome is caused by –
**Core Concept**
Zollinger Ellison syndrome (ZES) is a rare gastrointestinal disorder characterized by excessive gastric acid production due to a gastrin-secreting tumor, typically a gastrinoma. This condition leads to severe peptic ulcers, diarrhea, and other gastrointestinal complications.
**Why the Correct Answer is Right**
The correct answer is related to the underlying pathophysiology of Zollinger Ellison syndrome. Gastrinomas are neuroendocrine tumors that secrete excess gastrin, a hormone that stimulates parietal cells in the stomach to release gastric acid. This excessive acid production leads to the development of peptic ulcers and other gastrointestinal symptoms. The gastrinoma can be located in the pancreas, duodenum, or other parts of the gastrointestinal tract.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the cause of Zollinger Ellison syndrome. While gastrin is indeed the hormone involved, the specific type of tumor (gastrinoma) is the primary cause of the syndrome.
**Option B:** This option is incorrect because it refers to a different condition. Gastroesophageal reflux disease (GERD) is a common condition characterized by the reflux of stomach acid into the esophagus, but it is not the cause of Zollinger Ellison syndrome.
**Option C:** This option is incorrect because it refers to a different type of tumor. Carcinoid tumors are a type of neuroendocrine tumor, but they are not the primary cause of Zollinger Ellison syndrome.
**Clinical Pearl / High-Yield Fact**
A key clinical feature of Zollinger Ellison syndrome is the presence of multiple peptic ulcers, often in unusual locations such as the duodenum or jejunum. This is due to the excessive gastric acid production caused by the gastrinoma.
**Correct Answer:** C. Gastrinoma.