Flashcards in Icterus in horses Deck (36):
1
pre-hepatic icterus
problem with the rbc breakdown-haemoglabin-unconjugated bilirubin part of bile production
haemolysis - incr bilirubin production
primarily unconjugated bilirubin
2
haemolysis in horses
Neonatal isoerythrolysis - immunocompatibility between foeal + mothers RBCs
Infections eg EIA
Drugs eg penicillin
Toxins eg onion
Autoimmune HA – relatively rare in horses
3
hepatic icterus
Impaired hepatic uptake or conjugation
Increased unconjugated bilirubin
Common causes in horses : anorexia, acute hepatocellular disease
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anorexia + icterus
anorexia is most common cause of icterus in horses
10-15% horses look mildly icteric
may be due to ligandin shortage - protein needed for uptake of unconjugated bilirubin into liver
5
post-hepatic icterus
Impaired excretion of bilirubin
Cholangitis, cholangiohepatitis etc
Cholestasis if conjugated bilirubin >30% of total bilirubin shunts very uncommon
6
common clinical signs of liver dysfunction
depression
anorexia
colic
abnormal behaviour
weight loss
icterus
7
less common clinical signs of liver dysfunction
photosensitization
diarrhoea
bilateral laryngeal paralysis
haemorrhagic diathesis
ascites
dependant oedema
8
colic - suggests which hepatic dysfunction
hepatocellular swelling
biliary obstruction
9
weight loss - suggests which hepatic dysfunction
Chronic disease
Decreased intake
Metabolic dysfunction
10
hepatic encephalopathy
Severe hepatic dysfunction
clinical signs of cerebral disease vary - mild depression–head pressing
11
hepatic encephalopathy - pathogenesis
decr ammonia clearance
amino acid alterations - creates false neurotransmitters
12
photosensitisation
Phylloerythrin - photodynamic, made by bacteria in gut + excreted by liver
liver dysfunction = more phylloerythrin
UV exposure causes cell membrane damage + necrosis
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liver specific components of blood test
bile acids
SDH
GGT
14
what to look for on a hepatic ultrasound
size
Changes in echogenicity
Dilated bile ducts, choleliths, abscesses, neoplasia
15
hepatic biopsy can provide info for ___
diagnosis
prognosis
treatment options
16
treatment of HE
Sedation – care
Mannitol/hypertonic saline: cerebral oedema
Oral lactulose: limit ammonia absorption
Oral BCAA (branched chain amino acids): no evidence that this is beneficial
17
dietary modification
High carbohydrate, limited protein – protein source rich in BCAA
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anti-inflammatories
NSAIDS - Flunixin meglumine
DMSO
Corticosteroids - dexamethasone, prednisolone
19
pyrrolizide alkaloid toxicity - aetiology
Ingestion of plants containing pyrrolizidine alkaloids - Ragwort
Usually unpalatable
Long term ingestion (cumulative) – 4-12 weeks
20
pyrrolizide alkaloid toxicity - pathogenesis
Pyrrolizidine alkaloids metabolized by liver to toxic pyrrole derivatives
Pyrroles are antimitotic: cross link DNA + bind to nucleic acid and proteins within hepatocytes
Cells can't divide - megalocyte production (large RBC) - megalocyte death - fibrosis
21
pyrrolizide alkaloid toxicity - clinical signs + diagnosis
non-specific clinical signs
diagnosis - History of ingestion, Blood work, Biopsy - megalocytosis
22
pyrrolizide alkaloid toxicity - treatment + prognosis
no specific treatment
Poor prognosis
Typically death within 10 days of clinical signs of liver failure
Regeneration not possible if fibrosis present + megalocytosis extensive
23
theiller's disease a.k.a
serum sickness
acute necrotic hepatitis
serum associated heptitis
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theiller's disease
unknown cause
widespread hepatic necrosis
small liver at post mortem
no specific treatment
prognosis - poor if severe HE
25
tyzzers disease - cause by which bacteria
Clostridium piliformis
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tyzzers disease - clinical signs
May be none – found dead
Non-specific
Loss of suckle, depression, recumbency
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tyzzer's - diagnosis
antemortem – difficult
Definitive diagnosis – post mortem identification of organism
Multifocal hepatitis and enteritis
28
tyzzer's - treatment + prognosis
treat - antibiotics + supportive, only 1 ever successful case
prognosis - grave
29
cholelithiasis - diagnosis
Liver enzyme activity: GGT, SDH, AST
Ultrasound: ? Dilated bile ducts, cholelith
Biopsy: histopathology, culture
30
cholelithiasis - treatment + prognosis
treat - Antimicrobials: long term (weeks – months) Supportive care
prognosis - Depends on fibrosis, number and extent of choleliths, severity of clinical signs
31
hyperlipaemia
mostly in miniature breeds
incr risk of obese
due to -ve energy balance - disease, stress, pregnancy, lactation
32
hyperlipaemia - clinical signs
Lethargy
Anorexia
Weakness
Icterus
Mild colic, diarrhoea
Recumbency
+/- more severe signs of liver disease
33
hyperlipaemia - diagnosis
Breed
History
Clinical signs
Measure Tg in serum - Hyperlipidaemia, Hyperlipaemia
+/- liver biopsy
34
hyperlipaemia - treatment
reverse -ve energy balabnce
treat hepatic disease
eliminate stress/treat disease
inhibit further fat mobilization - insulin
incr triglyceride uptake by peripheral tissue - heparin
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hyperlipaemia - prognosis
poor once clinical signs seen
36