Hepatobiliary Disease in Large Animals- Intro

Question 1

define hepatic disease vs hepatic insufficiency

Answer 1

hepatic disease: any condition affecting the liver, wide range of problems

hepatic insufficiency:
-inability of liver to perform its normal functions
-most hepatic functions not impaired until greater than 80% of hepatic mass is lost

hepatic disease can be present even without accompanying hepatic insufficiency!

Question 2

describe clinical signs of hepatic disease

Answer 2

1. highly variable and non-specific
2. likelihood of liver disease increases when several signs are present in the same patient
3. may appear acutely once hepatic insufficiency occurs even with more chronic etiologies

Question 3

describe hepatic encephalopathy

Answer 3

1. complex clinical syndrome that accompanies severe hepatic insufficiency
2. changes in hepatic metabolism/detoxification alter cerebral neurotransmission
   -impaired energy metabolism
   -increased GABA-benzodiazepine tone due to ammonia
   -altered aromatic to BCAA ratio
   -cerebral hypertension and edema
   -inflammation

Question 4

describe clinical signs of hepatic encephalopathy

Answer 4

1. signs manifest as cerebral/forebrain disease
2. behavioral changes:
   -obtunded/stuporous to hyperexcitable to aggressive
   -head pressing
   -circling
   -ataxia
   -seizures are rare
   -must rule out other causes of cerebral disease

Question 5

describe icterus

Answer 5

1. yellow discoloration of tissues due to hyperbilirubinemia and subsequent deposition in tissues
2. most apparent in nonpigmented skin:
   -MM: gums, vulva
   -sclerae
3. pre-hepatic/hemolytic, hepatic, or post-hepatic

Question 6

describe weight loss with hepatic disease

Answer 6

1. associated with anorexia
2. more consistently present with chronic hepatic disease/insufficiency

Question 7

describe photosensitization with hepatic disease

Answer 7

1. secondary to increased phylloerythrin concentrations, exposure to UV light, and oxidative damage
2. erythema and edema first
3. pain, ulceration, necrosis, and sloughing follows
4. rule out primary photosensitization

Question 8

describe fever with hepatic disease

Answer 8

1. very nonspecific
2. accompanies several of the more infectious/inflammatory etiologies

Question 9

describe colic and hepatic disease

Answer 9

1. very nonspecific
2. may be related to acute hepatic swelling, bile obstruction, or (rarely) associated gastric impaction

Question 10

describe peritoneal effusion/ascite and hepatic disease

Answer 10

1. secondary to portal hypertension
2. clinical hard to detect in large animals

Question 11

describe ventral edema and hepatic disease

Answer 11

1. secondary to hypoalbuminemia and decreased oncotic pressure
2. fairly infrequent due to albumin’s long half life

Question 12

describe diarrhea and hepatic disease

Answer 12

1. may be related to portal hypertension, low oncotic pressure, deficiency of bile acids for digestion, and/or alterations in intestinal microflora
2. uncommon overall but more likely with chronic etiologies

Question 13

describe hemorrhage and hepatic disease

Answer 13

1. due to decreased synthesis of coagulation factors, particularly vitamin K-dependent factors (II, V, VII, X)
2. rare, but when present is a poor to grave prognostic sign

Question 14

describe hemolysis and hepatic disease

Answer 14

1. exact cause unknown
2. rare but when present is a poor to grave prognostic sign

Question 15

describe endotoxemia and hepatic disease

Answer 15

1. decreased removal of endotoxins
2. rare but when present is a poor prognostic sign

Question 16

describe clinical pathology and hepatic disease

Answer 16

1. liver specific:
   -SDH: hepatocyte injury/necrosis
   -GGT: cholestasis
   -bile acids: liver function
   -indicate liver disease (plus insufficiency for bile acids), but not a specific etiology
2. non-specific:
   -hyperbilirubinemia: hemolysis, anorexia (horses), certain drugs, liver disease

-if conjugated fraction is >30% of the total bilirubin, that indicated cholestasis

-hyperglobulinemia, hypoalbuminemia, hypoglycemia, decreased BUN, hyperammonemia: changes in protein/carb metabolism

-prolonged PT and APTT: prolonged PT first due to shortest half life of factor VII

Question 17

describe ancillary diagnostics for hepatic disease

Answer 17

1. transabdominal ultrasound: size, shape, appearance of parenchyma and biliary ducts
   -can’t rule in or out just because you can’t see the whole thing on US
2. liver biopsy: for histopath and culture, insight into diagnosis, prognosis, and treatment guidance
3. viral PCR testing
4. fecal diagnostics: fecal sedimentation for certain parasites
5. miscellaneous testing: peritoneal fluid analysis