Equine Liver Flashcards
What is jaundice?
Retention of bilirubin
Unconjugated form is more prominent in horses
What disease can mask jaundice and why?
Sepsis, as the mm are deep red/blue
Give some clinical signs of liver disease
Jaundice Weight loss Depression/CNS signs Photosensitisation (accumulation of phylloerythrin from chlorophyl) Haemorrhage Colic Oedema (due to hypoalbuminaemia, rare) Diarrhoea Dyspnoea (usually Ragwort; laryngeal paralysis) Anorexia/inappetence
How would you diagnose liver disease?
Liver enzymes
Serum bilirubin
Liver function tests (bile acids)
Blood ammonia (hyperammonaemia)
Give the functions of the liver
Digestive and secretory (bile salts) Metabolic (CHO, protein, fat metabolism) Detoxification/excretory Synthetic (clotting factors, proteins) Storage (vitamins, minerals)
Elevated GGT would indicate disease where?
Mainly biliary tract
Also specific to liver and pancreas
Elevated AST indicates what?
Hepatocellular damage
Elevated SDH indicates what?
Hepatocellular damage
What is the best test for liver function?
Bile acids
Continuous production so no need to fast
Correlated with severity
High blood ammonia levels may then cause what?
Encephalopathy (decline in brain function)
Which clotting factor has the shortest half life so is the first to have a prolonged PT (prothrombin time) when testing liver function?
VII
Give some risks of performing a liver biopsy
Haemorrhage (don't do if clinical coagulopathy) Inappropriate sample eg focal lesions Negative culture Infections Pneumothorax (rare)
Give some advantages of performing a liver biopsy
Biopsy score is the best indicator of prognosis in liver disease
(>6= poor prognosis)
Give some clinical signs of ragwort poisoning
Frequently only see signs of liver failure just prior to death
Early clinical signs are hard to difficult to detect and non-specific:
weight loss, behavioural change, anorexia
Other signs: inspiratory dyspnoea (laryngeal paralysis), severe CNS signs (hepatic encephalopathy), colic (gastric impaction), photosensitisation, haemorrhages, icterus
How do you diagnose ragwort poisoning?
History
Clinical presentation
Clinical pathology (GGT best enzyme to screen)
US (small liver may be difficult to find)
Biopsy (may not always see megalocytosis)
How do you treat ragwort poisoning?
Probably shouldn’t treat if bile acids >50 umol/L (>20=poor prognosis)
Can try supportive therapy (fluids, electrolytes, glucose)
Reduce hepatic encephalopathy (moderate to low protein diet, high branched chain amino acids -BCAAs, neomycin or metronidazole)
What causes cholangiohepatitis and cholelithiasis?
Ascending bile duct infection form GIT
Gram-negatives deconjugate bilirubin -> precipitates out and causes choleliths
Give the clinical signs of cholangiohepatitis and cholelithiasis
Fever, jaundice, colic
Marked increase in liver enzymes esp GGT
Biopsy may yield a positive culture (neutrophilic inflammation)
How would you treat cholangiohepatitis and cholelithiasis?
Long-term antibiotic therapy
What is chronic active hepatitis?
Any progressive inflammatory hepatitis
Biopsy may indicate immune-mediated (plasmocytic-lymphocytic)
How should you treat chronic active hepatitis?
Corticosteroids or other immunosuppressive medications eg azathioprine
Give the clinical signs of acute hepatitis
Severe CNS signs, jaundice, discoloured urine
Give some risk factors for hyperlipaemia
Breed Obesity Females Age vs insulin sensitivity (older) Underlying disease Transport, stress, lactation Starvation
Describe the pathogenesis of hyperlipaemia
Breakdown of stored fat (hormone-sensitive lipase) -> fatty acids to liver -> energy
Liver has poor ketogenic capability -> energy production is overwhelmed -> trigylcerides accumulate in liver and in plasma -> hyperlipaemia -> liver failure -> death
Ideally want to promote re-uptake in periphery by LPL (lipoprotein lipase) but LPL can’t keep up with HSL and liver
Give some presenting signs of hyperlipaemia
Non-specific: anorexia, weakness, lethargy, progress to more severe CNS and other signs
Signs may be due to hyperlipaemia, underlying disease, or secondary liver disease
Be aware of at risk animals eg colic surgery
How do you diagnose hyperlipaemia?
Cloudy serum
-Triglycerides >5 mmol/L = hyperlipaemia
-Triglycerides <5 (but over 1.5) = hyperlipidaemia
Presence of liver disease, azotaemia (inhibits LPL-lipprotein lipase)
How do you treat hyperlipaemia?
Treat underlying disease and parasites
Positive energy balance
Correct dehydration, electrolyte imbalance, acidosis
Other symptomatic therapy
Normalisation of lipid metabolism
-Insulin therapy? Risk of laminitis. Don’t give unless you have to.
What is the prognosis like for hyperlipaemia?
Guarded to poor
Worse if female, other organ involvement, poor initial response, failure to eat
Get horse out of the box
Give 2 causes of jaundice
Anorexia (causes hyperbilirubinaemia)
Haemolysis
How do you distinguish between the liver and spleen on ultrasound?
Spleen is more hyperechoic (brighter/more white) than liver
What should you do before taking a liver biopsy?
Check clotting profile
