GI: gastric disease Flashcards
What two enzymes are produced by the stomach to aid in digestion?
Pepsin, gastric lipase
A small amount of instrinsic factor is produced by what cells in the dog stomach?
Parietal cells and cells at the base of the antral glands
What breeds are predisposed to hypertrophic gastropathy?
Shih Tzu, Basenji
What breed is predisposed to atropic gastritis?
Lundehund
Prior to measuring serum gastrin, omeprazole/famotidine must be discontinued for how many days?
1 week
What non-gastric diseases can cause an increase in gastrin?
Renal and hepatic dysfunction
A gastric pH<3 with an increased serum gastrin raises concerns for that disease process?
Gastrinoma (Zollinger-Ellison)
Mast cell tumors and hyperhistaminemia can induce gastric acid secretion. What would the serum gastrin level be?
Low
In patients with achlorhydria, what would serum gastrin and gastric pH be?
pH >3 with increased serum gastrin (in humans, pH <2.5 with gastrin >1000 is diagnostic)
If a gastrinoma is suspected, what IV infusions can be given for further investigation?
Secretin or Ca - neither of these lead to release of gastrin in a normal animal, but both lead to gastrin release from a gastrinoma (highest 2 and 5 minutes after secretin, 60 min after Ca)
What are 3 consequences of a gastrinoma?
Gastric antral hypertrophy, hyperacidity, and ulceration
Where is the most common location for a gastrinoma?
Right limb or body of the pancreas
What percent of gastrinomas have metastasized at the time of diagnosis?
85% (LN, mesentery, spleen, liver)
What prostaglandin is gastroprotective?
PGE2
Where are NSAID induced ulcers typically located?
Antrum
What is the main side effect of omeprazole?
Diarrhea
What is octreotide?
Long acting somatostatin analog
How does octreotide affect gastrin/gastric acid?
Directly decreases the secretion of gastrin and therefore gastric acid production - can be used in gastrinomas
What is misoprostol and what is it used for?
PGE2 analog - protects against NSAID induced ulceration without altering gastric acidity
How does sucralfate work?
Binds to areas of denuded epithelial mucosa
Does prophylactic administration of misoprostol, cimetidine, and/or omeprazole prevent gastric erosions in dogs on steroids?
No, unlike with NSAIDs. Cause of ulceration due to steroid use is unknown
How do mast cell tumors induce vomiting?
Histamine causes H1 activation of the chemoreceptor trigger zone; H2 activation of gastric acid secretion
What is the mechanism of action for metoclopramide?
Antagonizes D2-dopamingeric and 5HT3-serotonergic receptors, agonist of 5HT4, cholinergic effects on smooth muscle
What is the mechanism of action of ondansetron?
Antagonized peripheral 5HT3 receptors
What is the mechanism of action of maropitant?
Antagonized NK1 (neurokinin 1) receptors
Maropitant has been associated with bone marrow hypoplasia in what age of dogs and cats?
Dogs <8 weeks, Cats <16 weeks
Gram negative or pathogenic bacteria induce the release of what cytokines from epithelial cells?
Proinflammatory - IL-8, IL-1 beta
Commensal bacteria induce the release of what cytokines from epithelial cells?
Immunomodulatory - TGFbeta, IL-10
What are two treatment protocols for Helicobacter in dogs/cats?
Metronidazole, amoxicillin and famotidine
Metronidazole, amoxicillin, bismuth +/- famotidine
Following treatment for Helicobacter, what percent of dogs had clearance of the bacteria at 6 months post treatment?
43% (high relapse rate)
Where do Helicobacter species colonize in the dog/cat?
Superficial mucus and gastric glands, particularly in the fundus and cardia
What histopathologic changes are more common in dogs/cats infected with Helicobacter?
Degeneration of the gastric glands, parietal cell necrosis, LP inflammation
What clinical conditions have NOT been linked to Helicobacter infection in dogs/cats?
Gastric ulceration, neoplasia, changes in serum gastrin, acid secretion
H. pylori induces much more severe proinflammatory cytokine and cellular responses in dogs/cats than natural infection with large Helicobacter species. What does this suggest?
Suggests large Helicobacter species are likely commensal. Loss of tolerance to commensal organisms, rather than pathogenicity of these organisms, may contribute to any disease condition
Hypertrophy of the fundic mucosa is associated with severe enteropathy in what breed?
Basenjis
Hypertrophy of the pyloric mucosa is found in what dog breeds and is associated with gastric outflow obstructions?
Brachycephalics, Lhasa Apso
What worm is capable of causing parasitic gastritis in cats?
Ollulanus tricuspis
How is Ollulanus tricuspis transmitted?
Cat to cat by eating vomit. Yes, eating vomit. Not found in feces
What endoscopic and histologic changes are found with Ollulanus tricuspis infection?
Rugal fold hyperplasia, 2-3mm nodules
LP infiltrates, lymphoid follicle hyperplasia, fibrosis
How is Ollulanus tricuspis infection diagnosed? Treated?
- Examination of gastric juice, vomit, or histopath. Not found in feces.
- Treatment = fenbendazole
What worm is capable of causing parasitic gastritis in dogs AND cats?
Physaloptera spp. 2-6cm long worms
What are the intermediate and paratenic hosts of Physaloptera?
Cockroaches, beetles
Lizards, hedgehogs
Atrophic gastritis characterized by reduction in parietal cells and hyperplasia of neuroendocrine cells has been associated with gastric adenocarcinoma in what dog breed?
Lundehunds
What is the suspected cause of bilious vomiting syndrome?
Motility disorder characterized by duodenogastric reflux
What is the mechanism by which erythromycin promotes gastric motility?
Releases motilin to act on motilin receptors and mimic phase III of the inter digestive migrating motility complex to empty the stomach of solids
What is the most common gastric neoplasm in dogs? In cats?
Dogs: Adenocarcinoma (47-72%)
Cats: Lymphoma
Where do gastric carcinomas most commonly occur in the dog?
Lesser curvature and pylorus
In a retrospective analysis of dogs and cats with gastric neoplasia, what percent of neoplasms were identified on ultrasound? On endoscopy?
50% on ultrasound, 95% on endoscopy
In a retrospective analysis of dogs and cats with gastric neoplasia, what neoplasm was the most commonly missed by ultrasound?
Lymphoma
In a prospective clinical trial, did laparoscopic assisted gastropexy affect GI transit time in healthy dogs?
Nope!
Does the cat esophagus enter the abdomen?
No - transitions directly into the stomach at the diaphragm level
How small must particles be to enter the duodenum?
2mm
How often do motilin plasma levels increase and what do they trigger?
Every 90-120 minutes, trigger migrating motor complexes
What cat breed can develop pyloric stenosis at a young age?
Siamese
Where are 5HT4 receptors located? Activation of these receptors results in what changes?
Located on enteric cholinergic neurons that innervate intestinal smooth muscle. Activation results in release of acetylcholine in the synaptic cleft and excitation of the cell membrane to increase motility
How does gastroesophageal intussusception differ from a hiatal hernia?
The gastroesophageal junction remains in the normal anatomic position with an intussusception
What is the average age of dogs with gastroesophageal intussusception?
Young - 13 months
What was the survival to discharge and MST for dogs with gastroesophageal intussusception?
88% survival to discharge, MST 995 days
What is common following surgical correction of gastroesophageal intussusception?
Persistent regurgitation, although some dogs had prior megaesophagus so ??
What two drugs have been shown to increase gastric transit time in healthy cats?
Metoclopramide, erythromycin (equally effective)
Chronic gastritis with lymphofollicular hyperplasia is associated with what other disease condition?
Chronic upper airway obstruction - brachycephalics, inspiratory dyspnea
Compared to dogs with chronic gastritis, dogs with gastric carcinoma displayed what changes?
Older (10 vs 6.5 yrs), lower BCS (3 vs 4.5), higher CRP (>25), low folate
Describe feline gastrointestinal eosinophilic sclerosing fibroplasia
Presence of eosinophilic masses confined to the GI tract and local LNs - cause unknown
What breed of cat is over-represented in cases of feline gastrointestinal eosinophilic sclerosing fibroplasia?
Ragdolls
What is a common physical exam finding in cats with feline gastrointestinal eosinophilic sclerosing fibroplasia?
Firm, irregular fixed abdominal mass in the cranial or mid-abdomen
In cats with feline gastrointestinal eosinophilic sclerosing fibroplasia, what are common clinicopathologic changes?
Peripheral eosinophilia (50%), hyperglobulinemia (70%)
When IV apomorphine is administered, what percent of dogs successfully vomit up foreign material?
76% in one study (495 dogs), 78% in another (61 dogs)
What factors were associated with successful emesis of foreign material after apomorphine? With unsuccessful emesis?
Success: young dogs, dogs ingesting fabric, leather, or bathroom waste
Unsuccessful: longer time between consumption and administration of apo, dogs that received opioids, sedatives, or antiemetics first
