GI Final--Cattley & Boothe Flashcards
3 components of the portal triad
portal venule
bile duct
hepatic artery
What is the idea of metabolic zonation of hepatocytes?
hepatocytes will vary in their functions and enzymes depending on their location along the gradient
4 functions of Kupffer cells
plasma protein turnover
clearance of endotoxin
erythrophagocytosis
phagocytosis of particulates (bacteria)
What are the 3 mechanisms by which jaundice can occur?
1) Overproduction (increased extravascular hemolysis)
2) decreased uptake, conjugation, and secretion (impaired liver function)
3) reduced outflow of bile (obstructed bile ducts)
Two major mechanisms of liver-associated ascites formation
portal hypertension (increased hydrostatic pressure)
decreased albumin production (decreased plasma oncotic pressure)
What are the 4 factors that contribute to CNS signs with hepatic encephalopathy
Ammonia elevation (increases glutamate and GABA)
endogenous benzodiazepine ligands from gut microbes can interact with GABA
astrocyte injury (ammonia related)
manganese–neurotoxic
Give the cause for each type of photosensitizaiton
1) Type 1
2) Type 2
3) Type 3
1) ingestion and deposition of preformed photoreactive pigments
2) congenital
3) liver failure
Which photodynamic pigment is involved in liver failure-associated photosensitization (type 3)
Phylloerythrin (PE)–produced from chlorophyll by GI bacteria and usually excreted in bile
Why are central lobular cells most susceptible to toxic drugs and chemicals?
they have the highest amount of CYP450 which activates toxins
What patterns of hepatocellular injury do we expect with infectious agents?
Random
4 patterns of hepatic fibrosis and what they are secondary to
diffuse (secondary to chronic parenchymal process)
biliary (portal inflammation)
postnecrotic (focally extensive necrosis)
centrilobular (congestive heart failure)
Prolonged/sustained increases in glucocorticoids are associated with?
glycogen accumulation
Concerning hepatic lipidosis, what are the 2 main categories of how it’s caused
1) physiological (dietary or adipose mobilization)
2) pathological (injury impairs utilization)
What type of shunt primarily impacts small breed dogs? what veins are usually anatomosed?
Extrahepatic congenital shunt;
portal vein and caudal vena cava OR azygous vein
Which type of shunt is seen in large breed dogs? what’s the cause?
Intrahepatic congenital shunt;
persistence of fetal ductus venosus
Thought they present similarly, how will congenital shunts and portal vein hypoplasia differ on clinical presentation?
Hepatic microvascular dysplasia WILL have portal hypertension and therefore, ascites
What type of hepatic necrosis presents with infectious canine hepatits
Centrilobular
different than most infectious agent which cause a random pattern
How does CAV-1 (infectious hepatitis) lead to DIC?
it likes to replicate in endothelial cells, and that damage leads to consumption of coag factors
Mutation of what gene in Bedlington Terriers predisposes them to copper storage hepatitis
Mutated COMMD1 gene
What is the function of the COMMD1 gene?
helps diret the ATP7B-Cu complex to the lysosome
The toxin associated with aflatoxicosis
Aflatoxin B1 (binds proteins, DNA, and RNA leading to cell injury and necrosis)
4 histopathic changes seen in horses with pyrrolizidine alkaloid (PA) toxicity
hepatocyte loss
fibrosis
bile duct proliferation
megalocytosis
These flukes reside in the bile ducts of sheep and cattle and lead to chronic cholangitis, liver atrophy, and poor body condition
Fasciola hepatica
These flukes of sheep and cattle migrate through the parenchyma and cause extensive damage; they occasionally become encased in fibrotic cysts
Fascioloides magna
Another name for:
1) Infection with Clostrium haemolyticum
2) infection with Clostridium novyi
1) bacillary hemoglobinuria
2) black disease
Both baciallary hemoglobinuria and black disease have spores that can be activated by?
tissue injury
2 causes of copper toxicosis in sheep
dietary excess
grazing Mb-deficient pastures
Mb usually binds copper in the gut to decrease it absorption
Most common cause of EPI in
1) dogs
2) cats
1) juvenile acinar atrophy
2) chronic pancreatitis
3 mechanisms of acute pancreatitis
1) obstruction of pancreatic ducts
2) direct injury to acinar cells
3) disturbed intracellular trafficking within acinar cells
No matter the mechanism of acute pancreatitis, what is the key event?
activation on trypsin
Which is associated with clinical signs:
1) gallbaldder mucocele
2) cystic mucinous hyperplasia
2) cystic mucinous hyperplasia
Which radiographic view do you start with if GDV is suspected?
Right lateral (do a left if right only show dilation)
During a gastropexy what layers s are being sutured together?
transversus abdominus
seromuscular layer of stomach
3 things to evaluate to determine gastric viability
visible arterial pulsations
color of serosa
thickness of gastric wall
With small intestinal surgery, you want to avoid which border?
mesenteric border—contains blood supply
When there is luminal disparity do you:
1) make the larger segment smaller to match the small one
OR
2) make the smaller segment larger to match the big one
2) Make SMALLER LARGER
Holding layer for intestines?
Submucosa
What type of suture material is best for intestinal anastomosis
small, synthetic absorbable (i.e. 4-0 PDS)
You should, if possible, incise _____ to the foreign body
proximal (orad)…closer to the mouth
Which suture pattern should never be used for an anastomosis
360* simple continuous pattern (can have purse string effect)
Primary complication with intestinal surgery?
Leakage
How to definitively diagnose a PSS?
Ultrasound
Biggest draw back for using suture material to attenuate a shunt?
doesn’t allow for gradual closure over time, which can cause acute portal hypertension
how long should supportive therapy be continued after PSS surgery?
at least 2 months
*includes low protein diet, lactulose therpay, and antimicrobial therapy
Which shunt type
1) extrahepatic OR
2) intrahepatic
offers a better prognosis?
Extrahepatic (easier to reach during surgery and more options for closure)
Two important muscles of pelvic diaphragm
levator ani (medial) coccygeus muscle (lateral)
Damage to this nerve can lead to fecal incontinence
caudal rectal nerve (supplies anal sphincter)
Colopexy is used to treat ______
deviation of the colon
Principle complication associated with perineal hernias?
Recurrence
The preferred approach for rectal/anal neoplasia?
rectal eversion
Rectal eversion is only for what type of neoplasms?
mucosal-based
