Liver/Pancreas/Peritoneum
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- Describe the postmortem changes observed in the liver.
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Autolysis: Soft, friable, red to gray, gas bubbles, pale "rose spots"
Imbibition of Bile: leakage of biel from the gallbladder and extrahepatic ducts
Pseudomelanosis: Contact with GI tract
Streamling of perfusion: especially prominent in horses - List the two congenital anomalies observed in the liver.
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Cysts: yellow to red content, bile duct origin
Porto: equal shunt - List and describe the types of physical injury that can be incured by the liver.
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Perforation: FB, parasites or biopsy
Rupture: caused by massive trauma (HBC), hepatomegaly (congestion, fatty liver, hepatitis)
Strangulation: diapragmatic hernia, occasionally get torsion of a lobe (usually left lateral lobe) - Describe the different types of pigments that can be found in the liver.
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Icterus: yellow to green liver, distended extrahepatic ducts and gallbaldder; yellow to orange bile casts in biliary tree
Hemosiderosis: brownish-black, hemolytic anemias (EIA) may cause; yellow-brown crystalline deposit in Kupffer cells
Melanosis: congenital, may be acquired in old sheep and cattle
Fluke Pigment: black excretory pigment acculmulated in periductal tissue and hepatic lymph nodes (Fe-porphyrin compound)
Carotenosis: yellow ether-souble pigment that can accumulate in the liver of animals fed large amounts of carotene - What are the causes of atrophy of the liver?
- Cachexia, starvation, chonic congestion, post-necrosis, external compression, cirrhosis, portocaval shunt
- What are the lesions associated with atrophy of the liver?
- Decreased weight, sharp edges, fibrotic
- What are the lesions of nodular hyperplasia of the liver?
- Scattered pale nodules, often cirrhosis present, common in old dogs, proliferation of hepatocytes but lack of normal achitecture
- What are the causes of hydropic degeneration of the liver?
- Hypoxia, anemia, septicemia, toxic injury, glucocorticoid hepatopathy
- What are the lesions assoicated with hydropic degeneration of the liver?
- Pale and swollen grossly with swollen vacoulated hepatocytes
- What are the causes of negative engery balance in the liver?
- Diabetes mellitus, ketosis, starvation, choline deficiency, advanced pregnancy, pregnancy toxemia of sheep, hyperlipidemia and hepatic lipidosis
- What are the lesions assoicated with fatty liver?
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Pale, swollen, friable. Histologically, spherical empty vacuoles in heptocytes
+/- floation in fixative/water - What are the causes of amyloidosis in the liver?
- Idiopathic or secondary to tissue-destroying process (abscesses, neoplasms, chronic inflammation)
- What are the lesions associated with amyloidosis in the liver?
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Swollen, pale firm liver
Homogenous eosinophilic deposits. - Describe focal necrosis. What is its significance?
- Scattered pale foci (1-2 mm in diameter) that give the appearance of a sawdust liver. Of little significance because of the great functional reserve of the liver.
- What can cause focal necrosis of the liver?
- Mild toxic damage and septicemia (salmonella, tularemia, pseudotuberculosis, listeria of fetus, pseudorabies, rhinopneumonitis)
- Describe centrilobular (zonal) necrosis.
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Mottled, slightly depressed red centers of lobules
Histologically, CL coagulation necrosis - What can cause central lobular necrosis of the liver?
- Hypoxia, anemia, shock, right heart failure, toxins (chemical, bacteria, plant), Rift Valley Fever, Infectious Canine Hepatitis
- List the 3 sequelae of centrilobular necrosis
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Regeneration without scarring
Regeneration with scarring
Death from acute or chronic hepatic failure - Describe the appearance of a liver with massive (zonal) necrosis.
- Scattered red swollen necrotic lobules. If chronic, irregular pitted surface from post-necrotic collapse and scarring. Histologically, coagulation necrosis and hemorrhage +/- involving scattered whole lobules, lobular collapse and scarring if chronic
- What can cause massive zonal necrosis of the liver?
- Nutritional deficiency (Se, Vit E), toxic injury (mycotoxins, plants), chemicals (cerosol, phosphorus, halogenated hydrocarbons)
- What is the sequelae of massive zonal necrosis of the liver?
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Death from acute hepatic failure
Healing from postnecrotic collapse and scarring - What is hepatosis dietetica of swine?
- Se-Vit E deficincy in growing pigs that causes massive zonal necrosis (with hemorrhage). May be accompanied by ascites, mulberry hear disease and white muscle disease
- List the causes of edema in the liver.
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ICH
Hepatosis dietetica - Describe the lesions of edema in the liver.
- Wet translucent distention of the connective tissue around the gallbladder, bile ducts and hepatic interstitium
- What is the cause of chronic passive congestion (nutmeg liver)?
- Right heart failure
- Describe the lesions associated with nutmeg liver.
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Gross: mottled with red central and yellow peripheral lobular appearance, swollen and congested if acute, but may be atrophied if chronic
Histologically: CL degeneration, necrosis and atrophy of hepatocytes, fatty change in peripheral-lobular hepatocytes, hemosiderin in Kupffer cells, post-necrotic fibrosis if chronic - What is the sequelae to chronic passive congestion in the liver?
- Ascites, subcutaneous edema (brisket disease) and eventual hepatic failure
- What are the causes of hemorrhage in the liver?
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Trauma
Massive necrosis
Parastic migration - What are the lesions associated with hemorrhage in the liver?
- Hemorrhage and necrosis, clot formation, scarring if chronic
- What is a portocaval shunt?
- Observed in dogs, this allows portal blood to bypass the liver, often produces hepatic encephalopathy and high blood ammonia leves, produces hepatic atrophy
- What are the causes of thrombosis and infacrtion of the portal vein?
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Bacillary hemoglobinuria of cattle
Phycomycosis - What is telangiectasis?
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Scattered purple groups of lobules filled with blood, common in cattle (idiopathic)
Histologically, coalesced sinusoids - In what species is peliosis hepatits commonly observed?
- Cats
- List the causes of necrotizing hepatitis.
- Infectious: ICH - adenoviruses, rhinopneumonitis, canine herpes infection, leptospirosis, toxoplasmosis and pseudorabies
- What is the pathogenesis of necrotizing hepatitis?
- Hematogenous infection by hepatotrophic agents
- What is the appearance of a liver with necrotizing hepatitis?
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Gross: swollen, pale, mottled friable liver (with gallbladder edema in ICH)
Histo: necrosis of hepatocytes, inculsion bodies, organisms, minimal inflammatory reaction, dissociation of hepatocytes (with lepto) - What are the causes of suppurative hepatitis (abscesses, suppurative cholangiohepatitis)?
- Actinomyces pyogenes, Streptococcus sp., Staphyloccus sp., Fusobacterium necrophorum, Clostridium piliformis
- List the 5 routes of infection for suppurative hepatitis.
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Secondary to caustic rumenitis
Secondary to omphalophlebitis
Secondary to hardware disease
Secondary to hematogenous spread in bacteremia
Secondary to ascending cholangitis - List the common bacterial pathogens to cause disease in the liver and the animals in which the infections are observed.
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Listerosis and Campylobacter fetus (neonatal lambs);
Actinobacillus equuli (foals);
Yersinia pseudotuberculosis (lambs);
Francisella tularensis (lamb/rabbit);
Salmonella (all);
TB (all);
Clostridium hemolyticum (cattle - fluke migration);
Clostridium piliformis (rodent, dog, cat -Tyzzer's Dz)
Leptospirosis
Chlamydiasis (birds) - What parasites migrate through the liver?
- Ascaris suum, Stephanurus dentatus, Strongylus, Fasciola hepatica and gigantica, Fascioloides magna, Dircrocoelium dendriticum, Metorchis conjunctus
- List toxins that cause damage to the liver.
- Plants (blue-green algae), Chlorinated tetracarbons, phosphorus, cresols, iron compounds, idosyncratic drugs, aflatoxins, mycotoxins, pyrrolizidne alkaloids, nitrosamine, copper
- What is serum hepatitis of horses?
- Sporatic occurence of acute liver failure with neurologic signs, jaundice that may occur 40-60 days following vaccination.
- What are the lesions assoicated with serum hepatitis of horses?
- Friable "dish-rag" liver with fatty change, bile stasis, necrosis and leukocytic infiltration
- What is cirrhosis?
- Progressive end stage chonic liver disease with NECROSIS, FIBROSIS, and REGENERATION (self-perpetuating)
- What are the lesions associated with cirrhosis of the liver?
- Atrophic, firm, nodular liver with extensive fibrosis, loss of parenchyma and ongoing necrosis and regeneration
- What is the pathogenesis of cirrhosis of the liver?
- Hepatic injury (toxic, nutritional, infection, congestion) --> initiates necrosis, fibrosis and regeneration --> repeated insults provokes self-perpetuating damgae that continues even if primary cause is removed
- What is the sequelae of cirrhosis of the liver?
- Chronic hepatic failure, ascites and portal hypertension
- List the 3 neoplastic diseases that can be found in the liver.
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Bile duct adenoma (adenocarinoma) found in the dog and cat
Hepatocellular adenoma (hepatoma) and carcinoma: usually bening in dogs and cats and malignant in cattle and sheep
Metastatic neoplasms (second to the lung) - What are common causes of obstruction of the gallbladder?
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Inflammation
Choleoliths
Parasties
External compression by neoplasms
Granulomas
Abscesses - What can cause edema of the gallbladder?
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ICH
Hepatosis dietetica - What are the lesions associated with hypoplasia of the pancreas?
- Lack of development of acinar tissue, duct system is prominent --> steatorrhea
- What can cause atrophy of the pancreas?
- Cachexia, starvation, chonic destruction (necrosis, inflammation, obstruction)
- What are the lesions of atrophy in the pancreas?
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Lack of zymogen granules.
Fibrosis if a destructive process has occured - Describe the lesions of nodular hyperplasia of the pancreas.
- Pale nodules comprised of proliferated acinar cells lacking normal architecture
- What are causes of necrosis in the pancreas?
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Nutritional (high fat, low protein) influence, bile reflux, toxic injury
Seen in obsese, old dogs usually females
Se deficiency in chickens - What is the pathogenesis of pancreatic necrosis?
- Activation of digestive enzymes in the gland --> autodigestion --> hemorrhagic necrosis and necrosis of peripancratic fat --> shock if recovery (often have multiple reoccurances)
- What is the appearance of necrosis in the pancreas?
- Red areas of hemorrhage, white plaques of fat necrosis (saponification), pancreas is firm, edematous, irregular and swollen
- What is the sequelae of pancreatic necrosis?
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Death from a single episode;
Mutliple episodes and eventually development of DM or acinar insufficiency;
Chronic interstitial pancreatitis - What are the causes of pancreatitis?
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Asending infection from the intestine
Hematogenous infection (toxo) - What are the causes of fibrinous peritonitis?
- FIP, Mycoplasma hyrhinis, Glasser's disease (Hemophilus parasuis), blackleg
- What are the lesions of fibrinous periototis?
- Yellow sheets and strands of fibrin adhering to viscera, excess serous to serosanguinous fluid in the cavity
- What is the sequelae to fibrinous peritonitis?
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Complete resoultion
Healing with fibrous adhesions
Death from septicemia - What are the causes of suppurative peritonitis?
- Contaminated wounds (post-castration), contaminated abdominal surgery, ruptured viscus, hardware disese
- What can cause granulomatous peritonitis?
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TB (pearl disease);
Systemic mycoses - What are the lesions associated with FIP?
- May have extensive fibrin and fluid accumulation throughout the cavity (wet) or scattered white foci of pyogranulomatous inflammation on the surface of the viscera (dry), may have accompanying pleuritis, ophthalmitis and meningitis
- What is the cause of abdominal fat necrosis in ruminants?
- Toxic injury --> fescue toxicity
- What are the common neoplastic conditions of the peritoneum?
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Lipoma: often multiple and pedunculated in horse (may produce intestinal strangulation)
Mesothelioma: primary tumor on serosal surface
Metastatic neoplasms: ovarian carcinoma common