Hepatology - equine Flashcards

1
Q

What are the functions of the liver?

A

Protein/carb/lipid metabolism
Bile excretion
Detoxification
Mononuclear phagocyte system

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2
Q

How much hepatic mass needs to be lost/not functioning to cause hepatic insufficiency?

A

80%

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3
Q

What is a sequalae of hepatic insufficiency?

A

Hepatic encephalopathy - neuro signs

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4
Q

What disease causes orange skin on a horse?

A

Cholangiohepatitis

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5
Q

What is regurgitation icterus?

A

Impaired excretion of bilirubin into the biliary tract

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6
Q

How does liver disease cause hepatogenic photosensitisation?

A

Increased blood conc of photodynamic agent - phylloerythrin
Phylloerythrin combined with IV creates free radicals which damage skin

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7
Q

How do you evaluate for liver disease in horses?

A

Serum bile acid concentration - very good screen for liver failure
Bilirubin - not a sensitive indicator, only increased in 25% of horses

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8
Q

What is different about the serum bile acid concentration testing in horses to small animal?

A

Dont have a gall bladder so dont need to do pre and post prandial

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9
Q

What change in protein synthesis do you see in the liver? What does it indicate?

A

Albumin level - if hypoalbuminaemic then means more than 80% of liver has been affected for more than 3 weeks

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10
Q

What are the liver enzymes in horses specific to hepatocellular disease?

A

SDH
GLDH
GGT
(ARG)

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11
Q

What equine liver enzyme has a major drawback?

A

SDH - doesnt survive in a tube

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12
Q

Which equine liver enzyme is the most sensitive indicator of hepatic disease/hepatocellular damage?

A

GGT

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13
Q

What are the drawbacks to GGT equine liver enzyme?

A

Higher in foals - from colostrum
Continues to rise for 1-2 weeks after liver improving
May not increase in chronic disease

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14
Q

What are the first line lab tests done if suspect liver disease?

A

GGT - evaluate for damage
Bile acids - evaluate function

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15
Q

When can you not do a liver biopsy in horses?

A

Hepatic lipidosis - will make liver shatter
If impaired clotting

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16
Q

What diagnostic imaging can you use to look at the liver?

A

Ultrasound

17
Q

How do you do an equine liver biopsy?

A

Ultrasound guided tru cut

18
Q

How do you treat hepatic insufficiency? How should you feed horses?

A

Supportive
High carb low protein diet, multiple small feeds, oat hay/grass
Paraffin/magnesium sulphate - reduce toxin absorption in gut

19
Q

How can you tell the difference between acute and chronic disease in horses?

A

Difficult
Onset of signs can be sudden in both
Chronic disease may show hyperglobulinaemia, hypoalbuminaemia and fibrosis

20
Q

What is theilers disease?

A

Acute hepatic failure caused by giving equine origin antiserum eg. tetanus antitoxin injection

21
Q

How do you approach bacterial hepatitis?

A

Liver biopsy - culture, histology
Supportive therapy
4-6 weeks of appropriate antibiotic

22
Q

What can be ingested by horses to cause chronic liver failure? What is the name of the disease it causes?

A

Ragwort - yellow plant
Megalocytic hepatopathy

23
Q

How does ragwort cause chronic liver failure?

A

Cumulative toxicity - eaten over a long period of time
Stop hepatocyte division so cells enlarge - megalocytes
These die and get fibrosis causing liver failure

24
Q

What are the clinical signs of megalocytic hepatopathy from ragwort?

A

4weeks-12 months after ingestion
Hepatic encephalopathy
Photosensitisation
Anorexia/weight loss
Icterus

25
Q

What is the prognosis of megalocytic hepatopathy from ragwort?

A

Poor prognosis - fibrosis limits regeneration

26
Q

What are the features of cholelithiasis in horses?

A

Intermittent signs of icterus, colic, weight loss
Dilated bile ducts on ultrasound

27
Q

What is non-septic hepatitis in horses?

A

Inflammatory infiltrate without infection

28
Q

What are some causes of non septic hepatitis?

A

Unknown aetiology - likely viral or toxins in hay

29
Q

How do you treat non septic hepatitis?

A

Corticosteroids, azathioprine

30
Q

What should you do after looking at liver enzymes and bile acids when investigating a suspected liver disease case?

A

Liver panel, clotting, biopsy