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59 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What are 3 indications for surgery on the liver?
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1) Biopsy
2) Tumor excision 3) Correction of porto-systemic shunts |
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How are percutaneous biopsies of the liver performed?
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Routinely ultrasound guided
-be careful with automatic biopsy in cats, creates a wave that can damage the liver |
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When is a punch biopsy used on the liver? What lesions?
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During a laparotomy
*For lesions in the middle of a lobe |
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When is a Guillotine technique used to biopsy the liver?
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For lesions at the edge of a lobe
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How can a Guillotine biopsy be used when the lesion is not at the tip but right on the edge of the lobe?
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make several loops so create hemostasis all the way around and cut the lesion out, want sutures to overlap so there's no area missed by suture so don't bleed
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What are 2 methods used for a partial lobectomy of the liver?
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Guillotine
Finger fracture |
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What is the preferred method for a biopsy when the lesion is more on the body of the liver lobe?
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Lobectomy (simpler and safer than finger fracture etc.)
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What are the 6 lobes of the liver?
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1) Left lateral
2) Left medial 3) Quadrate lobe 4) Right lateral 5) Right medial 6) Caudate lobe -caudate process of caudate lobe -papillary process of caudate lobe (more on left side of liver but hilus is on right so considered on the right) |
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What are the 3 DIVISIONS of the liver, based on blood supply?
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Portal vein comes in and there’s a right branch and then the major branch keeps going then central branch and then left branch and then keeps dividing more, portal vein brings 3 branches and goes to each division so think of right, central and left
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Why are right liver lobectomies much more difficult and have a higher mortality rate than left liver lobectomies?
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Right liver lobe is intimately involved with the caudal vena cava with the liver parenchyma encircling the vena cava
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What type of stapler can be used for liver lobectomies? Where do you put the staples
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Thoracoabdominal (TA) staplers
-fastest way to get liver lobe out -use staples at the hilus |
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What side of the liver do tumors in the liver seem to favor?
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Left side (easier to perform lobectomy)
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What is the prognosis of a massive hepatocellular carcinoma with surgical resection?
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the majority are enormous but if get all of tumor prognosis is excellent
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What is the definition of a porto-systemic shunt?
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Abnormal communication between venous system and the systemic venous system allowing blood from the portal system to by-pass the liver
-with shunt blood goes from portal vein---> hepatic vein--> caudal vena cava; bypasses capillary network through liver |
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What 3 arterial systems bring the blood that will eventually be drained by the portal vein into the liver?
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Celiac
Cranial and caudal mesentery arteries |
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What organs are drained by the portal system to the liver? (6)
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GI tract
Stomach SI Colon Pancreas Spleen (rectum is drained by systemic circulation) |
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What are the two portal systems in the body?
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1) Portal vein ( liver)
2) Pituitary (hypophyseal portal system) |
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What is the definition of a portal system?
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It goes through a capillary system so is drained by a capillary system instead of delivering the venous blood straight to the heart
-Hepatic portal vein--> capillary system in liver--> hepatic vein--> caudal vena cava--> heart |
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What are 2 unpaired veins in the body (i.e. no artery)?
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Azygos vein
Portal vein |
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What are the 2 main reasons that problems will arise in animals with portosystemic shunts?
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1) Metabolites of digestion (ammonia) and toxins are able to by-pass the liver and escape the metabolism
2) Liver lacks hepatotrophic factors -Insulin & glucagon |
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Why do animals with a Portosystemic shunt have microhepatica?
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Because lack the hepatotrophic factors insulin and glucagon which should go to the liver when its growing
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What type of porto-systemic shunt do small and toy breed dogs get > 90% of the time?
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Extrahepatic shunts
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What type of porto-systemic shunt do >75% of large breeds get?
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Intrahepatic shunts
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Portosystemic shunts are less common in cats but what type do they tend to get?
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Extrahepatic shunts
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What is a sign of portosystemic shunts unique to the cat?
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Copper-colored eyes
-seeing this justifies running bile acid tests |
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What are the 5 signs of hepatic encephalopathy?
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1) Seizures
2) Ataxia 3) Circling 4) Head-pressing 5) Blindness |
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What are 3 GI signs of a PSS?
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vomiting, diarrhea, anorexia
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What are signs related to the urogenital system caused by portosystemic shunts?
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Uroliths with or without urinary tract infection
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When will signs of a portosystemic shunt get worse?
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Classic history to hear its worse after eating a meal bc a lot of the toxins come from proteins so toxins absorbed from GI bypasses the liver and goes systemic
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A german shepherd comes into your clinic with a urolith and analysis reveals that it is ammonium biurate. What is the most likely cause of the stone formation?
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Liver disease
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What molecule is eventually broken down into uric acid in the mammalian system?
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Nucleic acids
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What happens to uric acid NORMALLY in the system? Compare this to what happens to animals with a portosystemic shunt.
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uric acid is not very water soluble so normally uric acid is converted to allantoin, the enzyme that allows this to happen is uricase and this is located in the liver, so if bypass the liver you’re not able to produce allantoin and have excess uric acid which is secreted by kidneys and not very water soluble so get stones= ammonium biurate
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What abnormal finding may be present on a CBC in a dog with a portosystemic shunt?
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*Microcytosis is common (60-72%)
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What does a decrease in albumin, glucose and cholesterol on a chem panel suggest?
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Liver failure
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Are liver enzymes elevated in a patient with a portosystemic shunt?
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They may or may not be elevated
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What is the golden standard for ruling out a portosystemic shunt?
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Bile acids test
-have to specifically order |
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What does a high bile acid mean?
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Implies LIVER DISEASE, have to perform further work up to figure out what type of liver disease
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How can you make a bile acids test more specific?
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Do pre and post prandial
-When eat gallbladder contracts an increases bile acids in GI, but in healthy animal 98% returns to liver, if animal has PSS then this goes into circulation= high |
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How can you tell if an animal has liver disease based on pre and post prandial bile acid measurements?
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If pre or post prandial is higher then 25 then animal has liver disease
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What type of imaging can be helpful for diagnosing a portosystemic shunt? (4)
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1) Ultrasound
2) *Nuclear scintigraphy -great, but not readily available 3) Portogram 4) MRA |
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What are 3 methods used to medically manage a portosystemic shunt?
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1) Low protein diet
-K/D -L/D 2) Oral antibiotic -to control intestinal bacteria 3) Lactulose |
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What are 3 types of oral antibiotics that can be used to medically manage Portosystemic shunts?
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1) Neomycin
2) Metronidazole- be careful 3) Amoxicilling |
W
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Why do you have to be careful using metronidazole in a dog with a portosystemic shunt?
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Metabolize din the liver and one of the side effects is seizures
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Why do we give animals with a portosystemic shunt lactulose?
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-Converts ammonia (NH3)--> ammonium (NH4+) and the positive charge makes it remain in the intestinal lumen --> increases ammonia excretion
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Why can animals given lactulose have diarrhea?
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Results in decrease intestinal transit time
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What 4 things should you do if a dog with a portosystemic shunt presents to you and is actively seizuring?
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1) Administer diazepam
2) Give an enema 3) Infuse lactulose rectally 4) Administer IV fluids (after do everything else) |
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What's the 3 reasons for administering fluids to an animal with a portosystemic shunt that is actively seizuring?
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1) Correct electrolyte imbalances
2) Correct pH imbalance 3) Correct hypoglycemia by adding dextrose (e.g. toy breed dogs) -doesn't hurt to give |
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Most patients will greatly improve with medical management of a portosystemic shunt. So why should you still operate?
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Usually of short duration, with 50% of dogs euthanized w/in 10 months
-dogs that do well long term are older and have a normal BUN |
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Why is it best to combine medical and surgical management for portosystemic shunt correction?
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*Surgery is NOT an immediate fix!!!!
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What are 2 surgical corrections used on extrahepatic portosystemic shunts?
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1) Ligature
2) Ameroid constrictor |
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What are 2 extravascular techniques used to repair an intrahepatic portosystemic shunt? 2 Intravascular techniques?
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-Extravascular: ligature, ameroid constrictor
-Intravascular: ligature, coils |
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Why can't we always just go in and completely occlude a portosystemic shunt?
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Some dogs will suffer from portal hypertension
-some dogs have a liver that isn't fully mature and hasn't seen much blood flow |
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********What are 4 signs of portal hypertension at surgery?
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1) Pallor or cyanosis of the intestines
2) Increased intestinal peristalsis 3) Cyanosis or edema of the pancreas 4) Increased mesenteric vascular pulsation *If see any of these remove whatever is occluding the shunt |
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What is an ameroid constrictor?
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Device that allows gradual occlusion of a PSS
-allows gradual increase in blood flow to liver = time to grow & accomodate to increased flow |
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How long does it theoretically take for a portosystemic shunt to completely close?
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4-6 weeks*** why we need to do medical management too
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portosystemic shunt repair on what division of the liver has the highest mortality?
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Right sided
-harder than left or central, have to go intravascular |
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What technique is used to correct most left sided and central division portosystemic shunts?
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extrahepatic, extravascular technique
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What are 4 postoperative complications of portosystemic shunt correction?
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1) Portal hypertension
-often life threatening 2) Post-ligation seizures 3) Failure to close or recanulization 4) Development of multiple extra-hepatic shunts |
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What postoperative complication of portosystemic shunt corrections is the worse negative prognostic indicator?
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Post-ligation seizures
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