Zollinger-Ellison Syndrome Flashcards
What are the primary symptoms of Zollinger-Ellison syndrome (ZES)?
Severe peptic ulcer disease
chronic diarrhea
gastroesophageal reflux disease (GERD).
What causes Zollinger-Ellison syndrome?
Gastrin-secreting tumors
usually in the pancreas or duodenum
leading to overstimulation of acid-secreting parietal cells in the stomach
What are the two main treatment goals for ZES?
-Control of acid hypersecretion to manage refractory peptic disease
-control of the gastrinoma, which is often malignant.
How are the terms “gastrinoma” and “ZES” different?
“Gastrinoma” refers to the neuroendocrine tumor (NET) secreting gastrin
while “ZES” refers to the clinical manifestations of the disease
What percentage of ZES cases are associated with multiple endocrine neoplasia type 1 (MEN-1)?
20-25%
whereas nearly 50% of patients with MEN-1 will have gastrinomas.
What is the average time from symptom onset to ZES diagnosis, and why is there a delay?
About 8 years, often due to the widespread use of PPIs, which mask symptoms.
What is the current surgical treatment focus for ZES?
Resection of the gastrinoma and long-term pharmacologic acid suppression
What is the second most common functional neuroendocrine tumor after insulinoma?
Gastrinoma.
At what age is Zollinger-Ellison syndrome (ZES) usually diagnosed?
It is most commonly diagnosed in the fifth decade of life, typically between ages 20 and 60
At what average age do patients with MEN-1 typically develop ZES compared to sporadic cases?
The average age of onset for MEN-1 patients is 33.2 years, compared to 43.5 years for sporadic cases
With which other syndromes is gastrinoma sometimes associated?
von Hippel-Lindau syndrome
von Recklinghausen’s disease.
What normally controls gastric acid secretion to maintain pH homeostasis?
Negative feedback from somatostatin release by gastric D cells
What are the most common presenting symptoms of gastrinoma?
Abdominal pain and diarrhea (reported in over 70% of cases)
What is the average delay from symptom onset to ZES diagnosis
Between 6 and 8 years
Where are gastrinomas most commonly found?
In the pancreas or duodenum, specifically within the “gastrinoma triangle.”
What anatomical boundaries define the gastrinoma triangle?
The cystic duct, the second and third portions of the duodenum, and the neck and body of the pancreas.
In which ectopic locations can gastrinomas occasionally occur?
The stomach, bile duct, periportal lymph nodes, lungs, heart, and ovaries
What is the most common location for gastrinomas in the duodenum?
The first portion of the duodenum, with incidence decreasing distally.
Are duodenal gastrinomas easy to detect preoperatively?
No, they are often very small and can be difficult to identify preoperatively and intraoperatively.
What is the incidence of duodenal versus pancreatic gastrinomas in MEN-1 patients?
MEN-1 patients often have multiple tumors in the pancreas or duodenum
most sporadic gastrinomas occurring in the duodenum
What is the prognosis for patients with pancreatic gastrinomas versus duodenal gastrinomas?
Pancreatic gastrinomas have a poorer prognosis due to a higher rate of liver metastases
How do liver metastases affect the prognosis of gastrinoma patients?
Diffuse liver metastases are associated with a 10-15% 10-year survival rate, whereas absence of liver metastases corresponds to a 95% survival rate
What is the significance of the primary tumor size in gastrinomas?
Larger primary tumor size is predictive of distant metastasis
What is the typical Ki-67 proliferative rate in gastrinomas?
Gastrinomas have a low Ki-67 rate, around 1% to 2%, indicating they are generally slow-growing tumors.
How does the rate of lymph node metastasis compare between duodenal and pancreatic gastrinomas?
Duodenal gastrinomas have a higher rate of lymph node metastasis (70%) compared to pancreatic gastrinomas (40%)
When should a patient be referred for a ZES workup?
In cases of refractory peptic ulcer disease
long-standing diarrhea
ulcer disease without H. pylori infection
or failure to improve after H. pylori treatment and acid suppression therapy
What additional findings suggest MEN-1 in a patient being evaluated for ZES?
The presence of hypercalcemia or nephrolithiasis, which warrants screening for both gastrinoma and MEN-1.
What is the initial diagnostic test for ZES?
Measurement of fasting serum gastrin levels.
What conditions can cause hypergastrinemia other than ZES?
Pernicious anemia
atrophic gastritis
H. pylori infection
gastric outlet obstruction
antral G-cell hyperplasia
retained antrum
renal failure
short bowel syndrome
Why can pharmacologic acid suppression with PPIs complicate the diagnosis of ZES?
PPIs can cause achlorhydria, leading to hypergastrinemia due to the absence of acid-mediated suppression of gastrin secretion
What fasting serum gastrin level strongly suggests ZES if gastric pH is also low (<2)?
A fasting serum gastrin level greater than 1000 pg/mL.
What is basal acid output, and what are the thresholds indicating ZES?
Basal acid output has a sensitivity of 98% for ZES if it’s greater than 15 mEq/hour in unoperated patients
or greater than 5 mEq/hour in post-resection patients
How long should PPIs be discontinued before fasting serum gastrin testing?
At least 72 hours, ideally 7 days; H2 receptor antagonists can be used during this time to control symptoms
What provocative test is used to confirm ZES in patients with fasting hypergastrinemia?
The secretin stimulation test.
overnight fast
intravenous bolus secretin of 0.4 μg/ kg
Blood samples of gastrin levels at 0, 2, 5, 10, 20, and 30 minutes following secretin administration
not necessary to discontinue PPIs or H2 antagonists for this test.