Chapter 95 Liver and Biliary System Flashcards
How many triangular ligaments are there?
Three:
One to R lateral, one to R medial, one to “L lobe”
Name the hepatic ligaments.
Coronary, tirangular, hepatorenal, lesser omentum (=hepatograstric + hepatoduodenal)
What % volume of blood does HA vs portal vein supply to liver?
And % oxygen supply each?
Portal vein supplied 80% of blood volume, HA 20%
Portal vein and HA supply 50% oxygen each
What artery does the cystic artery originate from?
Left branch of HA
What tributaries join the portal vein cranial proximal to the cofluence of cranial and caudal mesenteric veins?
Splenic vein and gastroduodenal vein (N.B. this is absent in cats).
Relevant re pringle manouvre - make sure to angle finger cranially to occlude gastroduodenal vein too).
The hepatic veins enter the CVC in a spiral fashion. Which side has the most caual entry?
R enter most caudal (usually within liver parenchyma)
L most cranial (usually close to where CVC passes through diaphragm)
Describe the borders of the epiploic formaen
Dorsal: CVC
Ventral: Portal vein and HA
Caudal: Mesoduodenum
Carnial: Liver
How many hepatic ducts are there in dogs?
2-8
When does cystic duct become CBD?
at entry of hepatic ducts
Where does the bile duct open?
What is the name of the sphincter?
Opens at major duodenal papilla
Sphincter of Oddi
How does feline CBD/pancreatic duct anatomy differ from dogs?
Dogs:
- Separate opening of CBD vs pancreatic duct (Duct of Wirsung) at major duodenal papilla
- Majority of pancreatic secretions via accessory pancreatic duct = Duct of Santorini (minor duodenal papilla)
Cats:
- Conjoined CBD and pancreatic ducts at major duodenal papilla
- Only 20% of cats have accessory duct (i.e. CBD disease/obstruction in cats may affect exocrin epancreatic secretions)
Where are the major and minor duodenal papillae located?
Major 3-6cm aboral to pylorus (usually 1-2cm distal to where CBD enters duodenum (i.e. 1-2cm intramural portion)
Minor 2cm aboral to major
List 6 broad functions of the liver
- Synthesis and clearance of plasma proteins:
- Carb and lipid metabolism
- Coagulation factor and anticoagulant synthesis: Almost all coagulation factors except vWf and VIII. Plasminigen, antithrombine etc
- Thrombopoetin synthesis
- Storage organ for vitamins fats, glycogen, zinc, copped
- Immune function: Reticuloendothelail function i.e. phagocytosis. Largest in body
How much hepatic function has to be lost before hypoalbuminaemia is evident?
70-80%
How much hepatic function capacity has to be lost for hypoglycaemia?
70-80%
How depleted do coag factors need to be before clotting time prolongation?
depleted to <15% of normal concentrations
What is the name of hepatic macrophages?
Kupffer cells
List 6 ‘ingredients; of bile
(BBBC…PW)
- Bile salts
- Bilirubin
- Bicarb
- Cholesterol
- Phospholipids
- Water
- Other ions
Where does majority of bilirubin come from?
80% from Hb breakdown
What are bile salts made from?
Cholesterol
What are bile acids conjugated with in dogs?
And cats?
Taurine or glycine in dogs
Taurine in cats
What does cholecystokinin do (stimulated by food in duodenum, released by SI cells)?
Caused GB contraction and Sphincter of Oddi relaxation.
List 2 functions of bile salts
- Emulsify fats
- Bind endotoxin to preven absorbtion
How is bilirubin excreted?
Bacteria convert bilirubin to urobilinogen
Urobilinogen converted to urobilin or stercobilin
90% excreted in faeces (small amoiunt in urine)
10% re-absorbed
What gives faeces the brown colour
Stercobilin
i.e. acholic faeces due to reduced bile flow
N.B. sterco means faeces!
What volume of of liver can be removed acutely?
70%
84% –> death (due to portal hypertension avoid portal pressure >16mmHg - create portocaval shunt if so)
How long does it take for near complete regeneration after 70% hepatectomy?
7 days on average (can be up to 10 weeks
List 2 factors that have been associated with reduced hepatic regeneration
Biliary obstruction and diabetes mellitus (reduced insulin. Insulin = potent hapatotrophic factor)
How long does it take for US detectable CBD dilation after obstruction?
And for intrahepatic dilation?
1-2 days for CBD dilation
1 weeks for intrahepatic ducts
List 7 pathophysiological consequences of EHBTO
- Hypotension
- Decreased myocardial function
- Coagulopathy: Lack of fat + fat soluble vitamin absorbtion (i.e. Vit K)
- Endotoxaemia: Absence of bile salts –> bacterial overgrowth + endotoxin absorbtion
- ARF: Endotoxin = potent vasoconstrictor –> tubular necrosis
- GI haemorrhage: Endotoxin mediated ischaemia
- Delayed wound healing: Decreases fibroplasia and angiogenesis
What are the 3 most common canine caused of bile peritonitis?
Trauma, ruptured GB mucocoele, necrotising cholecystitis
What % of canine and feline choleliths are radiopaque?
What are they most commonly made up of?
Dogs:
50% radiopaque
Calcium carbonate or calcium bilirubinate
Cats:
80% radiopaque
Calcium carbonate (mostly)
List 6 imaging modalities that can be used to investigate hepatobiliary disease
- Radiography
- US (+ US guided cholecystograpthy - not described in cases of obstruction)
- CT
- MRI
- Scintigraphy: Technetium 99 iminodiacetic acid derivates. Iv injection –> biliary excretion
- Endoscopic retrograde cholangiopancreatography
In scintigraphy for EHBTO, what duration is consitent with EHBTO
>3 hours for compounds to accumulate in SI
What is normal CBD diameter in dogs?
And cats?
3 mm in dogs
4 mm in cats
An option to evaluate GB emptying is to inject synthetic cholecystikinin (Saincalinde).
What % of Gb volume is emptied in normal dogs vs obstructed?
Normal = 40% emptied within 1 hour
Abnormal = <20% emptied within 1 hour
What % liver resection –> inc ammonia?
>60% hepatectomy –> inc ammonia
name hepatotoxic inhalation agent
halothane
What 4 organisms are most commonly cultured from liver?
Clostridium, E. coli, Enterococcus, Bacteroides
How do hepatic cultures relate to bile cultures?
No positive hepatic cultures with negative bile culture.
List 6 methods to improve hepatic exposure
- Release triangular ligaments
- Induce pneumothorax
- Pack swabs in front of liver
- Gastric stay sutures
- Caudal sternotomy
- Paracostal approach
List the 3 ways that hepatic vasulcar occlusion techniques are classified i.e. for control of extensive haemorrhage
- Control of CVP (<5cm H2O)
- Liver inflow occlusion i.e. Pringle manouvre)
- Liver inflow and outflow occlusion (i.e. Pringle + pre- and post-hepatic CVC)
CVP doesnt really make sense as a vascular occlusion technique but this is how its classified in tobias
What is the time limit for Pringle manouver?
20 mins
How does liver tumour blood supply differ from normal liver parenchyma?
95% perfusion from hepatic artery (c.f 20% from HA in normal parenchyma)
What was the cause of death in experimental dogs undergoing HA ligation?
How is this prevented?
Gangrenous necrosis
Abx
Consider propylactic cholecystectomy if time (cystic artery from left HA)
How does liver cytology compare to histo?
FNA 48% accurate
What was minor (PCv drop by 10% or more) and major (transfusion or death) of hepatic tru-cut biopsy.
What was greatest risk factor for bleeding?
22% minor, 6% major
Thrombocytopaenia
Name a cat specific complication of hepatic tru cut biopsy
Vagotonic shock
What is conversion rate of lap liver biopsies?
2-4%
How can life threatening portal hypertension be managed after e.g. liver lobectomy?
What options are available if staged resection feasible?
create portocaval shunt
Selective portal vein branch embolization/ligation to stimulate hepatic regenration of remnant liver before definitive lobectomy.
List the % volume of respective liver lobes
Caudate + R lateral = 28%
Central division = 28%
Left medial + lateral = 44%
List 3 benefits of selective arterial embolization/chemoembolization/chemo delivery.
What feature of hepatic tumours make them particulary suitable to these techniques.
- Increased local chemo concentrations (x10-50) and dwell times
- Reduced systemic toxicities
- Reduced tumour blood supply/oxygenation
Hepatic tumours receive 95% blood supply from HA (vs 20% in normal parenchyma)
What product is added to chemo for embolization?
Why
Iodized poppy seed oil (Lipiodol)
–> slurry + improved radiopacity (tumours lack Kupffer cells i.e. no clearance of fatty substances so chemo mixture is concentrated in tumour.
What is a complication of embolization?
Post-embolization syndrome (malaise, fever, pain)
Above what serum tbil level is icterus clincially visible
25-35 umol/L (= 1.5 - 2.0 mg/dL)
How long after EHBTO can it take fo rcoag tests to become abnormal?
10d
How is bile effusion diagnosed?
Effusion tbil >x2 serum tbil
Bile crystals/pigment on cyto
What is the Vit K dose
And ffp/whole blood volume?
1 mg/kg sc bid
FFP or whole blood at 10 ml/kg
What % of EHBTO dogs have positive bile culture?
And cats?
What organisms most common?
17 - 39% dogs
30 - 50% cats
E. coli, Clostridium, Enterococcus, Enterobacter, Bacteroides
List 2 options for management of ‘transient’ biliary obstruction
Stent of cholecystostomy tube
What is the main concern if need to do cholecystojejunostomy instead of CCD?
Gastric ulceration due to gastric acid oversecretion
(normally presence of bile in duodenum inhibits gastric acid secretion)
What is the recommended stoma lenght in cholecystoenterostomy?
>2.5cm
List 5 potential complications of cholecystoenterostomy
Stricture, ascending cholagitis, dehiscence, gastric ulceration, haemorrhage
What is shown in this image?
Human (Cotton-Huibregtse) polyethylene stent over a 0.03-inch hydrophilic guide
What were the 2 main complications of lap-assissted cholecystostomy tube placement?
Obstruction and early dislodgement (recommend tsi 3-4 weeks)
Comment re histo of canine hepatic abcesses
And feline?
No underlying neoplasia in dogs
25% neoplasia in cats (n.b. very few cases)
List some possible predisposing factors for canine hepatic abcesses
DM, recurrent UTI, Pancreatitis, pneumonia, GB rupture, long term pheno or corticosteroids
N.B. NOT neoplasia
What bacteria was most commonly identified in canine hepatic abcess?
E. coli
List 4 management options for canine hepatic abcess
- Surgery
- medical
- US drainage
- US drainage + ablation (half of volume drained 95% ethanol injected and left there for 3 mins - also reported for hepatic and renal cysts)
List some concurrent conditions with whihc liver lobe torsion has been seen
Hepatic abcess
Hepatic tumour
Diaphragmatic hernia
Septic peritonitis
GDV
Which liver lobe is most comonly affected in llt
left lateral
What is prognosis for LLT managed surgically?
excellent (11/12 survived)
What is the underlying lesion if GB mucocoele?
Cystic mucosal hyperplasia
Deficiency of what gene has been found in dogs with Gb mucocoele?
ABCB4 gene
What is the magnitude of risk factor for the following for having GB mucocoele:
Hypothyroidism
Hypoadrenocorticism
Hypothyroidism –> x3
Hypoadrenocorticism –> x29
What bacteria are most commonly isolated form Gb mucocoele?
E coli and Enterococcus
IN what % of GB mucocoele has concurrent EHBTO been documented?
30%
i..e ensure GB patency!
What is mortality rate following sx for GB mucocoele?
16 - 40%
Comment on Gb rupture vs mortality
No association unless septic
What 5 of canine choleliths had +ve culture (aerobic vs anaerobic)?
70% cultured positive for aerobic
55% for anaerobic
What is post-op mortality rate for cholelithiasis in dogs?
What factro was assocated with increased mortality
10%
Presence of EHBTO
What are the 4 general types of hepatic tumour?
Hepatocellular, cholangiocellular, neuroendocrine, mesenchymal
What are the most common hepatic tumour ‘type’
metastatic (haemoatopoetic and lymphoid)
Name a parneoplastic syndrome seen with hepatic masses
Hypoglycaemia
List the 3 types and (% occurence) of hepatocellular carcinomas
- Massive (61%)
- Nodular (29%)
- Diffuse (10%)
where does massive hepatocellular carcinoma most frequently occur and in what % of cases?
L lobe, 67% of cases (about 20% in middle vs R)
What is the met rate in massive vs diffuse or nodular hepatocellular carcinoma?
What are 3 most common sites?
Massive = 36% metastasis vs 93% in nodular/diffuse
LN (40/%), lungs (40%), peritoneum (20%),
What is the MST in surgicall yve medically managed canine massive hepatocellular carcinoma?
What factor was associated with poorer prognosis?
Surgery –> 1500d MST
Medical –> 270d MST
R sided tumour (n.b. NOT associated with completeness of excision)
What are the most common locations of bile duct carcinoma in dogs (intrahepatic ducts vs extrahepatic vs GB)
Intrahepatic (90%) > extrahepatic (10%) > GB (1%)
What factors has been associated with cholangiocellular carcinoma in humans (and found in 1 dog)?
Chinese liver fluke
What is the most common type of primary hepatic neoplasm in cats?
Bile duct tumours (benign bile duct adenoma (aka biliary cystadenoma) > carcinomas)
What was periop mortality for feline malignant biliary tumours?
And met rate?
100% periop mortality
67% metastasis
What are the two most common body sites for neuroendocrine carinomas?
GI and lungs
In canine hepatic neuroendocrine carcinoma, what % had diffuse disease?
And mets?
100% diffuse
93% mets
i.e. terribele prognosis. Sx not recommended
List 8 canine mesenchymal hepatic tumours
Haemangioma
Haemangiosarcoma
Leiomyosarcoma
Osteosarc
Chondrosarc
Fibrosarc
Mesenchymoma
(Rhabdosarc in cats. Not chodro in cats).
What was MST for cats undergoing spelnectomy for MCT (even with mets)
19 months
What was MST for dogs with histiocytic sarcoma managed with lomustine?
100d
What % of malignancies metastasise to liver?
30% i.e. most common site for mets.
What is the most common metastatic neoplasm of liver?
Lymphoma (60%) > carcinoma (20%) > sarcoma (15%)
