GI Flashcards
What is the cut off for feline small intestinal size radiographically?
No more than twice the high of the central portion of L4, or 12 mm.
What are the most common causes of hemoabdomen in a cat
Non neoplastic- 54%. Neoplastic- 46%
Define pure transudate
< 2.5 g/dL TP
<500 cells/ul
Define modified transudate
2.5-5 g/dL TP
300-5500 cells/ul
Define an exudate
TP >3 g/dL
Cell count > 5000-7000cells/ul
Describe ratio approach to small intestinal diameter measurement in cats
Ratio of maximal small intestinal diameter to the height of the cranial endplate of L2 should not be > 2
Describe ratio approach to small intestinal diameter measurement in dogs
Ratio of maximal small intestinal diameter to the narrowest width of L5 on a lateral radiograph should not be >1.6
According to silverstein, what is the sense/spec of the SNAP cpLI
Sensitivity 92-94%. Specificity 71-78%
According to silverstein, what is the sens/spec of the cPLI
82% sent with severe panc, 63.6% with less severe panc.
96.8% specificity
According to silverstein, what is the sens/spec of the SNAP fPLI
Sens 79%, Spec 80%
According to silverstein, what is the sens/spec of the fPLI
Sensitivity 67% in all cats with panc and 100% in cats with moderate to severe panc
Specificity 100%.
Risk factors for development of AP in dogs
Middle aged-older
Overweight
Hx of prior or recurrent GI signs
Concurrent endocrinopathies (DM, hypoT, HAC)
Yorkies, min schn, terriers may be at risk.
What electrolyte abnormality is prognostic in cats with AP?
hypocalcemia- associated with poorer outcome
T/F PLI is affected by renal disease and steroid administration
false
Evidence for early nutrition in AP in people
Fewer complications including fewer infections, decreased risk of MODS, decreased mortality rates, less expense, and shorter duration of hospitalization when compared to parenteral nutrition.
what are the functions of each of these cells in the stomach:
Parietal cells
Chief cells
Mucus- producing cells
Parietal cells- secrete hydrochloric acid
Chief cells- secrete pepsinogen
Mucus-producing cells- secrete bicarb
Life span of enterocytes at villus
2-5 days
What is the organism is implicated in histocytic ulcerative colitis of Boxer dogs? How diagnosed and treated?
E. coli.
Identify organisms with fluorescent in situ hybridization (FISH).
Treat with FQ.
Treatment for campylobacter
Erythromycin, enrofloxacin, cefoxitin.
Breeds with congenital megaesophagus
Wire-haired fox terriers Min SChn GSD Great danes irish setters labs newfies shar peis
Siamese cats
Causes of acquired Megaesophagus
**MG Addisons Lead and thallium poisoning Lupus Esophageal neoplasia Severe esophagitis Inflammatory myopathies Peripheral neuropathies
What type of food should be fed to animals with delayed gastric emptying
Frequent small meals that are low in fat and protein and high in carbs (cottage cheese, rice, pasta)
What cells store serotonin in the GI tract
enterochromaffin cells - secrete serotonin (5-HT) into lamina propria with overflow into portal circulation and intestinal lumen
What is the function of the 5-HT-1p receptors in the GIT
Initiates peristaltic and secretory reflexes
No drugs target this
What is the function of the 5-HT3 receptors in the GI tract. What drugs work here?
Activates extrinsic sensory nerves and is responsible for sensation of nausea and induction of vomiting from visceral hypersensitivity.
Ondansetron and granisetron are 5-HT3 receptor inhibitors.
What is the function of the 5-HT4 receptors in the GIT?
Increase pre-synaptic release of ACH and calcitonin gene-related peptide, thereby enhancing neurotransmission. This promotes propulsive peristaltic and secretory reflexes..
CIsapride is a 5-HT4 receptor agonist
What drugs are known to inhibit the metabolism of cisapride
Clarithromycin
Erythromycin
FLuconazole
Itraconazole
(metabolized by the liver by cytochrome p450)
MOA of reglan
Central dopaminergic antagonist and peripheral 5-HT3 receptor antagonist and 5-HT4 agonist.
What drug can be used to restore dopamine to ACH balance if adverse effects noted from raglan?
Diphenhydramine
Oral absorption of cisapride INCREASES/DECREASES with food.
INCREASES. Give 15 minutes before feeding.
What is MOA of erythromycin and clarithromycin’s effect in the GIT
Motilin receptor agonists. Stimulate migrating motility complies and integrate peristalsis in the GIT.
Also stimulate cholinergic and noncholinergic neuronal pathways that increase motility.
Increases gastroesophageal sphincter pressure, increases gastric emptying, accelerates colonic transit, stimulates canine but not feline colonic smooth muscle in vitro.
MOA of ranitidine/ nizatidine
Histamine H2 receptor antagonists.
Prokinetic activity due to acetylcholinesterase inhibition
Greatest activity in the proximal GIT.
What BUN/creatinine ratio is suggestive of GI Hemorrhage
> 20:1
What can cause a false positive result on the occult fecal blood test? What does this test measure?
Test detects peroxidase activity.
Diets containing red meat or with high peroxidase activity (fish, fruits, vegetables).
Peroxidase-producing bacteria in GI tract can also cause false positive result.
What % of feline esophagus is smooth muscle
Caudal 1/3.
In dogs, esophagus is entirely striated muscle
Where is the CRTZ and what is unique about it vs. the rest of the brain
Floor of the fourth ventricle- lacks intact blood-brain barrier.
What receptors are located in the emetic center? Where is the emetic center?
Medulla oblongata of the brain stem
Serotonergic (5HT1) and adrenergic (alpha2) receptors.
What receptors are located in the CRTZ
Dopaminergic (D2) Histaminergic (H1) Andrenergeic (alpha2) Serotonergic (5HT3) Cholinergic (M1) Neurokinergic (NK1) Enkephalinergic (ENK u, d)
What receptor does apomorphine stimulate to induce vomiting?
Dopaminergic receptors in CRTZ
Differences in vestibular stimulation of vomiting in dog vs. cat?
In the dog, vestibular stimulation feeds directly into CRTZ before activating the emetic center, vs. the vestibular system acts directly on the emetic center in the cat.
What receptors are located in the vestibular system to induce vomiting?
Histaminergic (H1)
Cholinergic (M1)
NMDA
what receptors are located in the cerebral cortex to induce vomiting and what stimulates them?
Anxiety/anticipation stimulates
Benzodiazepine receptor
Enkephalinergic opioid receptor
List at least 12 medications commonly assoc with diarrhea
H2 blocker Misoprostol PPI Oral antacids Quinidine, procainamide, digoxin ACEI B-blockers Azathioprine Cyclophosphamide Cyclosporine Mitotane Trilostane Methimazole acarbose Amitriptyline Parasiticides Bethanechol Clomipramine Cochicine Acetazolamide NSAIDS
T/F:
Diarrhea is most common from increased peristalsis rather than decreased segmental contractions
FALSE.
Diarrhea typically from decreased segmental contractions
T/F:
Anticholinergics decrease propulsive peristalsis and segmental contractions
TRUE.
Predispose to ileus.
MOA of opioid-containing antidiarrheals
Decrease/Increase propulsive contractions
Decrease/increase segmental contractions
Decrease propulsive contractions and increase segmental contractions.
Risk factors for leakage following intestinal anastomosis
pre-op peritonitis
intestinal FB
serum albumin <2.5
intraoperative hypotension
Where do the histamine blockers specifically work in the GIT?
H2RAs block histamine receptor on gastric parietal cell- competitively inhibiting gastric acid secretion.
Which of the following histamine receptor blockers have delayed absorption by food
Famotidine
Ranitidine
Cimetidine
Cimetidine
not ranitidine or famotidine.
which H2RA are metabolized by liver and which excreted in urine?
Famotidine- excreted unchanged in urine
Ranitidine and cimetidine- metabolized by liver.
What is cimetidine’s effect on hepatic blood flow?
Decreases by 20%
MOA of PPIs
irreversibly inhibit hydrogen-potassium adenosine triphosphatase on the luminal side of the parietal cell, thus stopping secretion of hydrogen ions into the gastric lumen.
Absorption of omeprazole is increased/decreased by food
Decreased
MOA of sucralfate
Binds to epithelial cells especially at erosions and ulcers, remaining there for 6 hours. Serves as physical barrier protecting ulcer from pepsin and bile acids.
Stimulates local production of prostaglandins and binding to epidermal growth factor, which favors mucosal repair
Adverse effects of sucralfate
Constipation
Adsorption of other drugs (enrofloxacin)
MOA of misoprostol
Prostaglandin E1 analog
Antacid and mucosal protective properties:
Stimulates secretion of mucus and bicarbonate and increases gastric mucosal blood flow
Antisecretory effect on gastric acid, acting directly on parietal cells.
Adverse effects of misoprostol
Uterine contractions, diarrhea
SE of maropitant in young dogs and what age?
Bone marrow hypoplasia when given to puppies younger than 11 weeks.
What affect do NK1 antagonists have on anesthetic drugs?
Reduce the MAC of sevoflurane.
Route of elimination of raglan
kidneys
What is the MOA of promazine derivative antiemetics
Antidopaminergic and antihistaminergic effects that block CRTZ and at higher doses the MVC.
Also have anticholinergic, antispasmodic and alpha blocking effects
MOA and contraindications of aminopentamide
anticholinergic used as antiemetic.
Used with caution in patients with glaucoma, cardiomyopathy, tachyarrythmias, hypertension, MG and gastroesophageal reflux.
Examples and MOA of cholinomimetic drugs as pro kinetic agents
Ranitidine and nizatidine- inhibit acetylcholinesterase.
Bethanecol - true cholinomimetic drug, binding muscarinic receptors.
Bethanecol works throughout GIT but ranitidine and nizatidine seem most effective for promoting gastric emptying
Define intra abdominal hypertension
Sustained or repeated pathologic elevation of IAP more than 12 mm Hg
Define abdominal compartment syndrome
Sustained increase in IAP of more than 20 mmHg that is associated with new organ dysfunction or failure
Four risk factors for ACS
1- diminished abd wall compliance
2- increased intraluminal content
3- increased abdominal content
4- capillary leak syndrome
Describe 4 grades of IAH and recommendations for treatment
1- IAP 12-15 mmHg - maintain normovolemia, look for underlying disease
2- IAP 16-20 mmHg- Volume resuscitation, consider decompression
3- IAP 21-25 mmHg- volume resuscitation, decompression
4- IAP >25 mmhg - decompression required
How much fluid should be used to fill the bladder for IAP monitoring?
0.5-1 mL/kg, maximum of 25 mL per patient of sterile 0.9% NaCl
How is IAP monitoring done
Insert urinary catheter, connect to 3 way stop-cock with syringe of saline and manometer. Fill bladder with 0.5-1 mL/kg saline. System is zeroed to the patient’s midline at symphysis pubis with the patient in lateral recumbency and the manometer filled with saline. Stopcock closed to fluid source so that meniscus in the manometer can drop and equilibrate with pressure in urinary bladder. Difference between the reading at the meniscus and the zero point is the IAP
What is the normal IAP
0-5 cm H2O - dogs. 4-8 cmH2O cats
What factors influence the IAP reading
body position body condition pregnancy increased abdominal wall tone- pain, anxiety eternal pressure- belly bandages volume of infusate
What is abdominal perfusion pressure
MAP- IAP
What are the sites for TFAST exam
- bilateral chest tube site (ribs 7-9)
- bilateral pericardial chest site - 5-6 ICS over heart
- sub-xyphoid view
What are A-lines
horizontal lines of decreasing echogenicity in far field of image, similar and equidistant from pleural line.
These are result of reverberation artifact.
May be seen in patients with and without pneumothorax
What are B-lines
A type of comet tail artifact.
These are reverberation artifacts originating from visceral pleura.
Hyperechoic vertical lines extending from pleural line to far edge of image, passing through A lines without fading.
Occasional B-line is normal but excessive B-lines or close together are indicative of interstitial-alveolar lung abnormality
What is the lung point
When moving the probe from a dorsal to ventral direction in a patient with pneumothorax, the point where the glide side returns = lung point.
What is Meissner’s plexus
Inner plexus lying in submucosa of GIT.
What is the stimulus for secretion, site of secretion and action of secretin
stimuli: acid, fat
site: S cells of duodenum, jejunum, and ileum
Action: stimulates pepsin secretion, pancreatic bicarbonate secretion, biliary bicarbonate secretion, growth of exocrine pancreas
Inhibits gastric acid secretion
What is the stimulus for secretion, site of secretion and action of gastrin
Stimuli: protein, distension, nervous control
Site: G-cells of antrum, duodenum, and jejunum
Actions- stimulates gastric acid secretion, mucosal growth
What is the stimulus for secretion, site of secretion and action of cholecystokinin
Stimulus: protein, fat, acid
Site: I cells of duodenum, jejunum, ileum
Action: stimulates pancreatic enzyme secretion, pancreatic bicarb secretion, gall bladder contraction, growth of exocrine pancreas
Inhibits gastric emptying
What is the stimulus for secretion, site of secretion and action of glucose-dependent insulinotropic peptide
Stimuli: protein, fat, carb
Site of secretion: K cells of duodenum and jejunum
Action: stimulates insulin release
Inhibits gastric acid secretion
What is the stimulus for secretion, site of secretion and action of motilin
stimuli: fat, acid, nervous system
Site: M cells of duodenum and jejunum
Action: stimulates gastric motility, intestinal motility
What hormonal signals are released after a meal to increase intestinal motility
gastrin, cholecystokinin, and insulin
Which two hormones inhibit intestinal motility
secretin and glucagon
What are the main electrolytes in saliva
high K and bicarb
low sodium and chloride
What is released by pyloric glands in antrum of stomach
Mainly mucus but also some pepsinogen and hormone gastrin
What do parietal cells secrete
hydrochloric acid as well as intrinsic factor, which is essential for absorption of vitamin B12 in the ileum.
What does acetylcholine stimulate, compare to gastrin and histamine
secretion of pepsinogen by peptic (i.e., Chief) cells, hydrochloric acid by parietal cells and mucus by mucous cells
Gastrin and histamine strongly stimulate secretion of acid by parietal cells but have little effect on other cells
At what gastric pH is gastrin secretion inhibited
less than 3
This is bc high acidity stimulates release of somatostatin from delta cells, which in turn suppresses gastrin secretion by G cells
AND the acid causes inhibitory nervous reflex that inhibits gastric secretion
What three hormones stimulate pancreatic secretion
acetylcholine, cholecystokinin, secretin
What are the crypts of lieberkuhn and what do they secrete
Lie between intestinal villi, have goblet cells, which secrete mucus and enterocytes secrete large quantities of water and electrolytes.
What are the following disaccharides broken into?
lactose
sucrose
maltose
Lactose- galactose + glucose
Sucrose - fructose + glucose
Maltose- glucose
Which glucose transporter is in the gut and causes transport of sodium with glucose into intestinal cells
GLUT1
Which neuroendocrine peptides inhibit vagal and spinal afferent neurons to result in delayed gastric emptying?
CCK
5HT- via 5-HT3 receptors
Which of these increase and which decrease GI motility: Ach GABA Substance P/Neurokinin A NO Serotonin VIP Somatostatin
Ach - increase GABA - decrease Substance P/Neurokinin A - increase NO - decrease Serotonin -increase VIP -decrease Somatostatin- decrease
what electrolyte abnormalities have been shown to slow intestinal motility?
hypokalemia
hypermagnesemia
hyper- and hypo-calcemia
Haworth JVECC 2014: Diagnostic accuracy of the SNAP and Spec cpl tests for pancreatitis in dogs presenting with c/s of acute abdominal disease.
Findings?
SNAP and spec cpl may provide false positive diagnosis for pancreatitis in up to 40% of dogs presenting for acute abdominal disease. Good overall agreement between tests but 4/38 dogs with positive SNAP and normal Spec.
