ZOLLINGER-ELLISON SYNDROME (GASTRINOMA) Flashcards
What is gastrinoma?
It is a gastrin secreting neuroendocrine tumor mostly located in the pancreas or duodenum
Are gastrinomas malignant or benign?
Very few can be benign but they are mostly malignant
What is gastrin?
It is a peptide hormone that stimulates secretion of gastric acid (HCl) from the parietal cells of the stomach and also helps with gastric motility (movement of food from the stomach to rest of the GI tract).
What cells secrete gastrin?
G cells in the antrum of the stomach or in the duodenum
How does gastrinoma work?
Since it is a a gastrin secreting tumor, it secretes a lot more gastrin than needed hence stimulating release of excess gastric acid which irritates the walls of the stomach/duodenum and causes peptic ulcer which is typically resistant to normal meds as well as diarrhea
What are the gastric pH levels and serum gastrin levels in patients with gastrinoma?
Low gastric pH levels in a patient with gastrinoma due to high acidity in the stomach (the more acidic the lower the pH). Also the serum gastrin levels are increased
What are the risk factors for gastrinoma?
Male sex
30-50 years
Multiple endocrine neoplasia type 1 (MEN 1)
What are the Sx of gastrinoma?
Recurrent therapy resistant peptic ulcer
Abdominal pain
Diarrhea
Steatorrhea
Upper GI bleed(due to bleeding peptic ulcer) - vomiting bright red blood, Melena stool (dark stools)
Weight loss ( due to inactivated pancreatic enzymes
What is seen on an EGD?
The best test is an eosophagogastroduodenoscopy (EGD) to see the upper GI tract which normally reveals multiple ulcers in the duodenum especially and thick gastric folds
Investigations for gastrinoma
Esophagogastroduodenescopy
Gastric pH- reduced
Serum gastrin levels - increased > 1000pg/ml
Secretin stimulation test
When is the secretin stimulation test done in gastrinoma investigations?
It is conducted when the serum gastrin test is inconclusive because they are increased but not up to 1000pg/ml.
Secretin in healthy patients technically should inhibit gastrin secretion but in
it rather increases the secretion of gastrin by two fold the baseline level or more.
This confirms gastrinoma
When is imaging done in gastrinoma?
It is done only after gastrinoma diagnosis is confirmed to localize the tumor. CT/MRI scans are good imaging methods as well as endoscopic USG
Treatment of gastrinoma
To reduce the gastric acid secretion, proton pump inhibitors are given eg. Omeprazole
In non metastatic gastrinoma; surgical resection of the tumor is done
In metastatic gastrinoma- chemotherapy
Why would a person need b12 supplements after gastrectomy for gastrinoma?
Because the parietal cells in the stomach would have secreted gastric acid which absorbs vitamin B12 in the stomach hence vit B12 supplements have to be given to the patient now since the stomach has been removed
