GI: Cases Flashcards
A patient presents with the following, which is concerning for…
- indegestion, abd. pain, oily diarrhea
- relief via eating and antacids
zollinger-ellison syndrome
What imaging modality is used to assess potential ulceration in zollinger-ellison syndrome?
endoscopy
What four lab tests can be administered to evaluate for zollinger ellison syndrome?
Serum gastrin, Basal Gastric H+, Pentagasatrin stimulation test, secretin stimulation test
What results would you expect in zollinger-ellision when taking a serum gastrin and basal gastric H+ secretion?
highly elevated
What is the expected result of pentagastrin stimulation test in zollinger-ellison?
no increase
what is the expected result of secretin stimulation test in zollinger-ellison?
increase to 1000 pg/ml
With zollinger-ellison, what may be seen on CT?
gastrinoma
Laproscopic surgery is definitive tx for zollinger-ellison. What drug should be given while awaiting surgery?
omeprazole (PPIs)
What is the cause of excess gastrin release in Zollinger-ellison? Is it regulated by feedback mechanisms?
gastrinoma
no feedback regulation
Where are gastrinomas commonly located?
duodenum or pancreas
What doesn’t pentagastrin stimulation (a gastrin analogue) have any effect in zollinger-ellison?
H+ secretion already maximal
In the secretin stimulation test, secretin stimulates which cells to release gastrin?
gastrinoma cells, not G cells
What causes steatorrhea in zollinger-ellison?
pancreatic lipase inhibition due to low pH
a complete ileal resection would result in a loss of _____ meters.
2 to 4 meters
An ileal loss of more than _____ cm will distrupt enterohepatic circulation of what substance?
100 cm
bile salt recovery
What is causing steatorrhea in ileal resection
liver cant replete bile salts fast enough, fecal loss is too great
What is the mechanism by which cholestyramine can treat diarrhea?
they limit cl- and fluid secretion, reducing diarrhea
Why must b12 be injected in patients with ileal resection?
The IF-b12 complex is absorbed in the ileum
What is the most common site of gastric ulcer caused by h. pylori?
antrum
h. pylori releases what which breaks down protective mucous?
cytotoxins
What allows h. pylori to survive the acidic environment of the stomach?
urease conversion of urea to NH3 to NH4+
leads to alkalinization
In the duodenum, H. pylori decreases the secretion of what substance, which leads to duodenal ulcer?
bicarb
What three tests are available for diagnosing H. pylori?
h. pylori Ab tests, C13-urea breath test, endoscopic biopsy
C13 urea is metabolized to what by h. pylori urease which can be measured upon expiration?
CO2-13
