Liver disease Flashcards
Clinical signs of hepatic dysfunction
Lethargy/inappetance
Weight loss
Colic
Photosensitisation
Encelopathy (change in mentation?)
Diarrhoea
Jaundice (usually only seen in haemolysis rather than liver disease)
Oedema (hypoalbuminaemia)
Coagulopathy
Or none!
Prognosis of liver disease
If signs then prognosis guarded
How useful are clinical signs in determining prognosis of a horse with liver disease?
Clinically normal horses may well have significant hepatic disease
When signs of hepatic insufficiency are present then the prognosis is guarded to poor
Liver enzymes
ALP - biliary
AST - hepatocellular, can go up in muscle disease
GGT - biliary, can also be elevated in GI disease
GLDH - hepatocellular
Biliary damage markers in horses
GGT and ALP
GGT can also be increase in GI disorders
Hepatocellular damage markers in horses
AST and GLDH
AST can also go up in muscle disease
Functional parameters of liver
Albumin
Globulins
Bile acids
Bilirubin
Urea
How useful is blood biochemistry for liver disease in horses?
Blood test results offer diagnostic and prognostic guidance but are frequently misleading
Why perform a liver biopsy?
Confirms presence of liver disease
Guides treatment selection
Provides reliable estimate of prognosis
When to perform a liver biopsy
Clinical signs
Clinical pathology results
One horse in herd has suspected liver disease, test herd mates
When not to performa liver biopsy
Hepatic lipidosis - because liver may rupture
Colic - can induce transient liver insult
Where to perform liver biopsy
Hip to horse
Scan dorsal to ventral in each intercostal space
Check from 15th to 10th ICS
Pause to watch lung
Check left and right sides of the horse
Measure depth of liver
Method of taking a liver biopsy
Sharp stab incision with number 15 scalpel blade - large enough to insert biopsy needle without dragging skin
Stand hip to horse
Insert and fire biopsy needle
Withdraw biopsy needle
Administer NSAIDs and possibly antimicrobials
How many biopsy samples do you need to take to overcome inaccuracy
> 10 complete portal tracts need to be examined so 2 or 3 biopsies
Potential complications of liver biopsy
Haemorrhage
Peritonitis/enterocentesis/colic
Pneumothorax/pleuritis
Specific diagnoses that can be made from histopathological assessment of liver biopsy
Amyloidosis
Neoplasia
Marked eosinophilic infiltrate -> MEED (multisystemic eosinophilic epitheliotrophic disease)
Septic cholangiohepatitis
Pyrrollizidine alkaloid toxicity
Haemosiderosis
Septic cholangiohepatits
Look for neutrophilic portal infiltration on the report
rarely diagnosed
Ragwort toxicity
Megalocytosis
Rare cause of liver disease in the UK
Avoid presumptive diagnosis - take biopsy
Haemosiderin deposition
Look for deposition haemosiderin in a proportion of hepatocytes
Severe deposition (>50%): poor prognosis
Excess dietary iron is deposited as haemosiderin
Might cause outbreaks of hepatic insult
Horses are never iron deficient, but can get toxicity
Chronic active hepatitis
Used to be more common
Look for mononuclear infiltrate in the portal areas (lymphocytes and plasma cells)
Aim of treatment is to reduce inflammation and risk of fibrosis development
Fibrosis
Treat with prednisolone and azathioprine
Spotty necrosis
Look for focal aggregates of neutrophils in hepatic parenchyma
Common finding in liver disease outbreaks - check herd mates
Signs that can suggest a prognosis?
Fibrosis
Irreversible cytopathology
Inflammatory infiltrate
Haemosiderin accumulation
Biliary hyperplasia
