Liver 1 Flashcards
1
Q
What is the liver responsible for?
A
- Clearance of gut-derived toxins
- Produces and acivates clotting factors
- Production of proteins, cholesterol, bile, glucose, BUN
2
Q
What are the lobes of the liver?
A
Left- medial and lateral
Right- medial and lateral
Quadrate
Caudate- 2 processes: caudate and papillary
3
Q
Which lobe is associated with the gall bladder?
A
Quadrate
4
Q
What are the large blood vessels in the liver?
A
Portal vein, hepatic artery, hepatic vein/vena cava
5
Q
What are the large biliary ducts?
A
Common bile duct and cystic duct
6
Q
What are the components of the biliary system?
A
- Common hepatic duct
- Cystic duct
- Gall bladder
- Common bile duct
Many branches are intrahepatic
7
Q
What is bile made up of?
A
- Water and electrolytes
- Bicarbonate
- Bile acids
- Cholesterol
- Phospholipids
- Bilirubin
8
Q
What are bile acids for?
A
Absorption and digestion of fat and fat soluble vitamins
9
Q
T/F: Bile is not the main elimination route of cholesterol.
A
False
10
Q
What is bile release stimulated by?
A
CCK and secretin
11
Q
What is the difference in the anatomy of the major duodenal papillae between the dog and the cat?
A
Dog: pancreatic duct and bile duct enter duodenum at separate places
Cat: pancreatic duct and bile duct join and enter the duodenum at the same place
12
Q
What is a lobule?
A
Hexagonal plate of hepatocytes radiating out from a central vein
- Portal triads are at the edges of lobules
13
Q
What are portal triad?
A
Collection of the there major vessels surrounding lobules
- Hepatic artery: oxygenated blood
- Portal vein: venous blood from abdomen
- Bile duct: carries bile away to larger intrahepatic ducts and then the GB
14
Q
What is an acini?
A
A cone of tissue that runs for zone 1 to 3
15
Q
What is a limiting plate?
A
Peri-portal hepatocytes
16
Q
What is zone one and what kind of injury is it most prone to?
A
Area closest to the portal triads that is most prone to hepatotoxins
17
Q
What is zone 2?
A
The area between zones 1 and 3
Nothing really special…..
18
Q
What is zone three and what kind of injury is it most prone to?
A
Area around the central vein that is most prone to hypoxia
19
Q
What is seen in the limiting plate in chronic hepatitis?
A
Inflammation and necrosis
20
Q
How much of the blood supply to the liver passes through the portal vein?
A
75%
21
Q
What organs drain into portal circulation?
A
Small intestine, pancreas, spleen, stomach
22
Q
T/F: Anything that can effect blood flow can effect liver enzyme values even if there is no specific liver disease.
A
True- anemia, shock, heart failure, etc
23
Q
How much of the blood supply to the liver passes through the hepatic artery?
A
25%
24
Q
Where d the branches of the hepatic artery and portal veins empty into?
A
Sinusoids
25
What are sinusoids?
Vascular channels lined circumferentially by hepatocytes that empty into the central vein
- Highly fenestrated endothelial cells
26
What is the space of disse and what does it do?
Area between the endothelial cells and hepatocytes
Site of plasma filtration and a large part of the lymph supply
27
Where do the central veins go?
Coalesce into larger hepatic veins and dump into vena cava
28
What are bile canaliculi made up of?
Basal aspect of hepatocytes joined together in junctional complexes- form the space of the bile canaliculi
29
What is contained within the bile ducts?
Products secreted by hepatocytes flow through canaliculi into bile ducts
30
What is the flow in he canaliculi relative to the blood flow in the liver?
Opposite
31
What is the flow from canaliculi to gall bladder?
Canaliculi-- intrahepatic bile ducts-- common bile duct-- custic duct-- gallbladder
32
What does the gall bladder do?
Storage and concentration of bile during fasting
| Expulsion of bile when needed
33
What are kupffer cells, where are they found, and what do they do?
- Liver macrophages
- Located in sinusoids
- Scavenge bacteria and other foreign materials
34
What are some clinical signs or presenting concerns of animals with liver disease?
Can be normal with labwork changes
Weight loss, vomiting, diarrhea, lethargy, icterus/jaundice, peritoneal effusion, acholic feces, hepatic encephalitis, abdominal pain, enlarged or small liver
35
What is acholic feces indicative of?
Bile duct obstruction or cholestasis
36
What are some CBC findings in patients with liver disease and what are they indicative of?
- Regenerative anemia if toxin, GI bleed, coagulopathic
- Normocytic normochromic anemia in chronic disease
- Microcytosis in congenital/acquired shunts
- Thrombocytopenia: lepto or coag issues
- Thrombocytosis: chronic blood loss, Cushing's disease
37
What are the serum chem findings in patients with liver disease and what are they indicative of?
Increased cholesterol: cholestatic disease
Decreases cholesterol: shunts and failure
Increased bilirubin: cholestatic disease, EHBDO, sepsis and hemolysis
Increased BUN: GI bleed
Decreased BUN: shunting or failure
Albumin: decreased with PSS and dysfunction
Hypoglycemia: dysfunction, shunts
Hyperglycemia: concurrent diabetes mellitus?
38
What are the UA findings in patients with liver disease and what are they indicative of?
Hyposthenura and isosthenuria common in extra and intra hepatic diseases
- PSS often PU/PD
- Glucoseuria: copper disease or lepto
- Bilirubinuria: abnormal in CAT
- Ammonium biurate crystals: shunts or failure
39
What can radiographs and US tell you when evaluating liver disease?
Radiographs: hepatic size, mineralization in liver or GB, mass lesions
US: masses, blood flow and shuntning, clots, gallbladder patency, shape, echogenicity, allows for aspirates/cultures of paranchyma and bile
40
T/F: Normal appearance of the liver on an ultrasound definitely rules out liver disease.
False
41
What can be diagnosed on cytology of the parenchyma of the liver?
- Hepatic lipidosis
- Some neoplasias like lymphosarcoma
- Vacuolar hepatopathy
42
What are some additional lab tests that are useful in working up a liver disease patient?
- Bile acids
- Protein C
- Coag profiles
- Lepto and other infectious disease tests
- Fecal analysis for parasites
43
When should you biopsy the liver?
When other diseases have been ruled out non-invasively and you're stuck
44
T/F: Biopsy is not the best way to identify primary paranchymal diseases as most conditions can be diagnosed on cytology of FNA.
False- also helps guide treatments
45
What should ALWAYS be run prior to performing an intestinal biopsy?
Coag profiles- usually within 1 day of procedure
46
What are the pros/cons of needle biopsies of the liver?
- Can be done percutaneously via US
- Less invasive
- Can't monitor hemostasis directly
48% correlation to surgical biopsy
47
What are the different types of surgical biopsies and what is the advantage?
Laparotomy and laparoscopy
Allows for direct hemostatic control and provides best diagnostic pieces
48
When should you pursue laparotomy over laparoscopy?
When you need to assess or biopsy other organs
49
What are the different stains you can use to evaluate liver histopathy and what are they diagnostic for?
```
H&E- routine
Masson's trichrome- cirrhosis and fibrosis
PAS- ceroid lipofuscin/lipid
Rubeanic avid/Rhodanine- copper
Congo red- amyloid
Perl's stain- iron
```
50
What cultures can you run on liver tissue and which is more diagnostic?
Anaerobic and aerobic cultures
Bile usually is more diagnostic than liver tissues so culture both if possible
51
T/F: Liver enzyme elevations are often nonspecific clues and are not diagnostic for disease.
True- some have indications but mostly are not very useful on their own
52
What are the three patterns of elevation in liver enzymes?
Hepatocellular, cholestatic, and mixed
53
How is most liver disease caught?
On routine bloodwork of apparently healthy pets
54
What is the half life of ALT (alanine aminotransferase) in the dog?
56 hours
55
Where is ALT usually located and what is an elevated value indicative of?
Cytosol of hepatocytes
Elevations indicate inflammation or necrosis
56
What should you suspect if ALT decreases or normalizes but you find other evidence of hepatic synthetic factor decreases?
Loss of functional liver mass
57
Where is AST (aspartate aminotransferase) usually located?
Cytosol and mitochrondria of hepatocytes and myocytes
58
What does an elevated AST mean?
Compare to ALT.
Hepatocellular or myocellular damage
Less specific than ALT
59
How can you tell that an elevated ALT is associated with liver or muscle damage?
If muscular origin, CK will also rise
Hepatocellular will have a normal CK
60
What is the half life of AST in the dog and cat?
12 hours in dog
| 77 min in cat
61
What will the expected AST and ALT values be relative to each other with irreversible liver injury?
AST > ALT
62
What conditions can effect hepatocellular enzymes?
Primary liver disease, infection, hepatotoxicity, reactive disease, hepatic abscess, liver lobe torsion, hyperthyroiidism
63
What values are associated wtih cholestasis?
ALP, GGT, total bilirubin, increased cholesterol
64
Which animal is ALP (alkaline phosphatase) cortisol induced?
Dogs ONLY
65
What are other things that can contribute to increased ALP?
Bone growth and osteolytic disease
| Small contributions from intestine kidney, liver, bone
66
What are increased ALP usually induced by?
Hepatocellular injury to canalicular membranes of hepatocytes
67
T/F: Increased ALP can be neoplasia induced.
True- hepatocellular carcinoma, LSA, osteosarcoma, mammary carcinoma
Increased ALP is a negative prognostic indicator for osterosarcoma patients
68
T/F: ALP source should be differentiated as adds to clinical diagnosis.
False- supportive but does not add to clinical diagnosis
69
What is the half life of ALP in the dog and cat?
70 hours in dogs
| 6 hours in cats
70
T/F: ALP is very specific for hepatobiliary disease in the cat.
True
71
Where is GGT (gamma-glutamyl transpeptidase) normally found?
Membrane bound on biliary surfaces
- Pei-portal hepatocytes
- Minimal contribution from kidney and pancreas
72
T/F: GGT is more specific for cholestasis than ALP.
True
73
What is the half life of GGT in the dog?
80 hours
74
What are some conditions that can cause elevations in cholestatic values?
```
Extrahepatic conditions- pancreatitis, IBD, masses, endocrine, sepsis
Breeds
Drug induced
Primary cholangitis/cholangiohepatitis
Benign nodular hyperplasia
```
75
What enzymes elevate first in cholestasis, what enzymes elevate later?
AST and ALT first
| ALK and GGT later
76
What is bilirubin derived from?
Breakdown of hemoglobin from RBCs and myoglobin
77
What is bilirubin a test of?
Hepatic function
78
What is the difference between conjugated and unconjugated bilirubin?
Unconjugated- bound to albumin
| Conjugated- made water soluble in bile for excretion into intestine and clearance in feces
79
What levels of bilirubin will produce pigment change in the skin and the serum?
2. 0-3.0 = skin
| 1. 0-2.0 = serum
80
What does an increased bilirubin level support?
Diagnosis involving hemolysis or hepatobiliary disease
81
How long does it take bilirubin to clear from the skin?
Depends on cause, usually takes several days once cause is resolved
82
Where is bilirubin conjugated?
Liver
83
What disease will present with higher amounts of unconjugated bilirubin versus conjugated?
Hemolytic disease or hepatic deficiencies
84
What are other values associated with hepatic function?
Bile acids, ammonia, clotting factors, synthetic factors (BUN, albumin, cholesterol, glucose)
85
What are bile acids derived from?
Cholesterol- cholic and chenodeoxycholic
86
What are bile acids conjugated to for excretion?
Glycine, taurine, glucuronic acid, and sulfates
87
T/F: Bile acids undergo enterohepatic recycling.
True- 96% that is excreted is reabsorbed and secreted back into bile canaliculi
88
T/F: Enterohepatic recycling is impaired with disease and can result in inappropriate excretion of bile acids in the feces.
False
89
Bile acids are useful to run to assess hepatic function in what kind of patients?
Non-icteric
90
What is the procedure for testing bile acids?
Measure pre feeding and 2 hours post feeding
91
What are increases in bile acids associated with?
Shunts, MVD, hepatic disease, failure, cholestatic disease
92
What are normal bile acid values?
Pre
93
What clotting factor does the liver NOT produce?
VIII
94
What should you give prior to liver procedures to help clotting abilities?
vit K1
95
What are clotting factor deficiency associated with?
Poor absorption of vit K and decreased activation associated with cholestasis or hepatic dysfunction
96
What percentage depletion is needed to increased clotting times?
70%
97
What values will you see with decreased hepatic function?
Prolonged: PT and PTT
Decreased: BUN, cholesterol, albumin, glucose
98
What is protein C and what is it associated with?
Anticoagulant protein made in the liver
Deceased values associated with poor function or perfusion, synthetic failure, shunts
Can differentiate MVD and shunts
99
What is the significance of ammonia?
Liver removes ammonia from circulation and enters urea cycle or consumed in synthesis of glutamine
Increases and be used to confirm hepatic encephalopathy but is not definitive for it
