Lecture 35 4/15/25 & 4/22/25 Flashcards by Danika Boltz

What are the functions of the liver?

-bile production and excretion
-protein synthesis
-regulation of glucose
-uptake of fatty acids
-elimination of ammonia
-metabolism of drugs and toxins

How well did you know this?

Not at all

Perfectly

What are the characteristics of Kupffer cells?

-fixed tissue macrophages in the liver
-conduct phagocytosis and release cytokines
-control endotoxemia

How well did you know this?

Not at all

Perfectly

What are the characteristics of hepatic insufficiency?

-requires at least 60 to 80% loss of function
-can occur with hepatic dz or hepatic failure

How well did you know this?

Not at all

Perfectly

What are the characteristics of liver disease presentation?

-signs are not often noticeable until dz is advanced
-signs are often similar irrespective of underlying cause

How well did you know this?

Not at all

Perfectly

What are the common clinical signs of liver dz?

-lethargy
-anorexia
-weight loss
-icterus
-colic
-hepatic encephalopathy

How well did you know this?

Not at all

Perfectly

What are the mechanisms of hepatoencephalopathy?

-nitrogenous waste/ammonia build up
-false neurotransmitters/GABA
-cerebral edema

How well did you know this?

Not at all

Perfectly

What are the signs of hepatoencephalopathy?

-head pressing
-dementia
-blindness
-seizures

How well did you know this?

Not at all

Perfectly

What are additional clinical signs that may be seen with liver dz?

-diarrhea
-hemorrhage
-fever
-hemolysis
-photosensitization

How well did you know this?

Not at all

Perfectly

What are the characteristics of photosensitization?

-secondary
-may be caused by phylloerythrin
-animal may have dermatitis and/or be pruritic
-limited to white areas of the body

How well did you know this?

Not at all

Perfectly

Which lab values are used to evaluate for liver dz?

*AST
-produced by liver and muscle
*SDH
-specific for hepatocellular damage
-labile with a short half-life
*GGT
-indicates biliary tract damage or cholestasis
*ALP
-can indicate biliary tract dz or cholestasis
-also produced by GI, bone, and placenta
*LDH
-not specific for liver dz
*arginase
-specific for hepatocellular dz
-short half-life

How well did you know this?

Not at all

Perfectly

What is the most common cause of hyperbilirubinemia in the horse?

fasting/anorexia

How well did you know this?

Not at all

Perfectly

What are the characteristics of bile acids?

-sensitive indicator of hepatocellular and/or biliary dz
-assesses liver function
-no post-prandial increase due to horses not having a gall bladder; only need a single sample and feeding time is not important

How well did you know this?

Not at all

Perfectly

Which other lab values may be abnormal in the face of liver dz?

-glucose
-total protein; esp. albumin
-fibrinogen
-BUN
-ammonia
-coagulation parameters

How well did you know this?

Not at all

Perfectly

What are the characteristics of ultrasound location for visualizing the liver?

*right side:
-best visualization
-ultrasound on a line between ICS 5-6 and ICS 15-16 from the tuber coxae to the elbow
*left side:
-ICS 6-9 below the lung

How well did you know this?

Not at all

Perfectly

What are the characteristics of the starry sky ultrasonographic pattern?

-associated with fibrosing hepatic granulomas
-incidental finding in most cases

How well did you know this?

Not at all

Perfectly

What are the characteristics of liver sampling?

-can try an aspirate or take a biopsy
-must assess clotting function before taking a biopsy
-coagulation abnormalities are found in over half of horses with liver dz, but biopsy complications are not common

How well did you know this?

Not at all

Perfectly

Which other diagnostic tests can be used to assess liver dz

-scintigraphy
-laparoscopy

How well did you know this?

Not at all

Perfectly

Which blood tests are most useful and should be prioritized in a suspected liver dz patient?

-SDH
-GGT
-serum bile acids

How well did you know this?

Not at all

Perfectly

What are the poor prognostic indicators for liver dz?

-high serum bile acids
-histologic inflammation
-hypoalbuminemia
-decreased BUN

Which categories of disorders are associated with increased liver enzymes in horses?

-inflammatory/infectious
-toxins
-neoplasia
-congenital
-miscellaneous/idiopathic

What are the steps to therapy for liver dz?

-treat underlying cause
-fluid therapy if indicated to maintain hydration, glucose, and electrolytes/acid-base
-decrease production and absorption of protein metabolites/ammonia
-change diet to have low protein, higher carbs, and good fats
-B vitamin supplementation
-NSAIDs
-antibiotics as indicated
-therapy for hyperlipidemia
-use drugs with hepatic metabolism with caution
-corticosteroids
-vitamin K1
-avoid sunlight

Which products can be used to decrease production and absorption of protein metabolites such as ammonia?

-mineral oil
-activated charcoal
-lactulose-disaccharide
-neomycin

What is the therapy for hyperlipidemia?

-maintain energy intake*
-insulin to inhibit hormone sensitive lipase
-heparin to stimulate lipoprotein lipase

When is surgery used as a treatment for liver dz?

-cholelithiasis
-chronic biliary obstruction

What are the characteristics of milk thistle?

-low oral bioavailability in horses -safe -increased antioxidant activity with increasing dose

What are the characteristics of SMA-3?

-increases liver glutathione -may help minimize oxidative injury

Which anti-fibrotic drugs can be used in the treatment of liver dz?

-pentoxyfilline -colchicine -corticosteroids -ursodeoxycholic acid

What are the characteristics of Theiler's disease?

-aka idiopathic acute hepatic dz, serum hepatitis, or serum sickness -common cause of equine hepatitis -mortality rates between 50 and 90% -acute to subacute onset -generally associated with use of equine biologic; tetanus antitoxin most common -viral cause; equine viral hepatitis

What are the characteristics of the equine viral hepatitis viruses?

-Flaviviridae family -Hepacivirus genus -small, enveloped, ssRNA viruses -spread via blood-to-blood contact

What are the four viruses identified in equine viral hepatitis?

-Theiler's disease associated virus -equine hepatitis virus -equine pegivirus -equine parvovirus

What are the characteristics of equine viral hepatitis diagnosis and prognosis?

-more common in adults than foals -diagnosed through history, signs, biopsy, and PCR -poor prognosis

What are the implications of equine viral hepatitis?

-most plasma products are now being screened -blood and stem cell donors at many facilities (including UT) are now being screened

What are the characteristics of Tyzzer's disease?

-caused by Clostridium piliformis -spores are in soil and are ingested orally -typically occurs around 7 to 42 days of age -signs are non-specific; animal is often found dead -median survival time is 30 hours

Which parasites can cause parasitic liver dz?

-Parascaris equorum -large strongyles -Echinococcus granulosus

What are the characteristics of pyrrolizidine alkaloid (PA) toxicity?

-common in horses -can occur with senecio, amsinckia, heliotropium, and crotolaria plants -plants are in pasture or in contaminated hay -generally a chronic, low-level exposure

What are the characteristics of the megalocytic hepatopathy that occurs with PA toxicity?

-pyrroles inhibit cellular division -hepatocytes enlarge and become megalocytes -cell death and fibrosis occurs -liver ultimately shrinks -process is generally chronic but signs may appear acutely -no specific therapy/antidote

What are the characteristics of alsike clover toxicity?

-common clover found in pasture mix -signs only occur if alsike "takes over" pasture -causes periportal fibrosis

What are the management steps for PA and alsike toxicities?

-evaluate other horses on property -remove animals from the source

What are the characteristics of chronic active hepatitis?

-chronic progressive hepatopathy -undetermined etiology; may be autoimmune or a hypersensitivity -causes hepatocellular necrosis, fibrosis, and cirrhosis -treated with corticosteroids and antibiotics if concurrent with cholangitis

What are the characteristics of cholelithiasis/cholangitis?

-biliary tract inflammation occurs -can be bacterial -may lead to calculi -signs include fever, icterus, and abdominal pain -most common in middle-aged horses -lab parameters include markedly increased GGT, neutrophilia, and hyperfibrinogenemia

How is cholelithiasis/cholangitis diagnosed and treated?

-ultrasound showing dilated bile ducts and/or stones -biopsy to do histopath. and culture and sensitivity -treated with antibiotics; typically TMS for 4 to 6 weeks

What is the presentation for hyperlipemia/hepatic lipidosis?

-any breed, but commonly in ponies, AMH, and donkeys -occurs with stress or pregnancy

What are the characteristics of hyperlipemia?

-negative energy balance occurs due to pregnancy, lactation, stress, or underlying dz -fatty acids mobilize and go to the liver where they are stored -triglycerides are released into circulation -liver enzymes become elevated

What is the therapy for hyperlipemia?

-maintain energy balance -treat concurrent dz -minimize stress -inhibit fat mobilization -increase triglyceride uptake by peripheral tissues

What is the prognosis for hyperlipemia?

guarded to poor

What are the characteristics of hepatic neoplasia?

-primary hepatic tumors are rare; hepatoblastoma can occur -metastatic neoplasms are typically lymphosarcoma or melanoma

What are the characteristics of congenital liver abnormalities in horses?

-rare -portosystemic shunts have been reported