Icterus in Horses Flashcards
What is important to remember about a horses biliary system? How does this affect bile acid analysis?
They have no gall bladder and thus secrete bile acid constantly. Therefore there is no need to take two measurements for bile acids.
How common is pre-heatic icterus in horses?
Relatively uncommon
What can cause heamolysis in horses?
Neonatal isoerythrolysis EIA drugs Toxins Autoimmune HA
What are common hepatic reasons for icterus in horses?
ANNOREXIA, acute hepatocellular disease
What is uncommon post-hepatically in horses?
Shunts
When should one think about liver disease in an icteric horse?
When it is still eating, not a foal and not pale.
What are the main clinical signs of liver failure in horses, are they specific?
Depression and annorexia - non specific
Colic - hepatocellular swelling, biliary obstruction (often will see a mild colic)
Weight loss
What is a cardinal sign of HE in horses?
Head pressing
What is the cause of photosensitization in icteric horses?
Phylloerythrin is no longer conjugated and excreted by the liver. Cells are then more responsive to UV
What needs to be done to diagnose liver disease?
Clinical signs
Bloods
Ultrasound
Biopsy
What tests are specific for the liver?
Increased bile acids
Increased SDH
Increased GGT
Why is abdominal ultrasound not that helpful in diagnosing liver disease?
It can only view ~20% of the liver as most of the liver is covered by lung tissue.
What can findings from a hepatic biopsy be used for?
Dx, Px, Treatment
What are the general principles of liver disease treatment in horses?
Suportive - maintain liver until regeneration. If fibrosis is severe this is less likely :
- Fluids/Acid base
- Glucose
- ABs????
- Anti-inflammatories
What are the priniciples of HE treatment?
- Sedate
- Mannitol/hypertonic saline - brain oedema
- Oral lactulose - limitis ammonia absorption
- Oral BCAAs (no evidence of efficacy)
What antiinflammatories can be used in liver disease? What should be remembered with corticosteroid use?
NSAIDs
DMSO
Cortico - link between these and laminitis
Pentoxifylline
What is the pathogenesis of Pyrolizidine alkaloid toxicity?
Meabolized by liver to toxic pyrrole derivatives . These are antimitotic and xlink DNA and bind to nucleic acid and proteins within hepatocytes. Cells cant divide and become megalocytes which will die and fibrose.
What can cause cholelithiasis?
parasites
Ascending biliary infection/inflammation
Biliary stasis
What clinical signs are strongly suggestive of cholelithiasis?
Fever+Icterus+Colic
How is cholelihiasis diagnosed?
Liver enzyme activity, ggt, shd, ast
Ultrasound (maybe)
Biopsy
How is cholelithiasis treated?
Antimicrobials Suportive care DMSO Anti-inflammatoris Others
When should hyperlipeamia be strongly suspected?
Obese pony breeds/ minature horses.
What causes hyperlipaemia?
Negative energy balance
How does hepatic lipidosis differ in horses compared to cats?
Horses very good at producing TGs and these are over produced so build up
How can HL be diagnosed?
Breed History Clinical signs Serum TGs (liver biopsy)
What are the principles of hyperlipaemia treatment?
1.Reverse te NEB
2.Treat hepatic disease
3.Eliminate stress/primary disease treatment
4. Inhibit fat mobilisation (insulin)
5.Increase uptake by peripheral tissues
(heparin - although likely that lipoprotein lipase is already maximally active)
