Lecture 5: Liver 2 Flashcards
Dogs recovering from or vaccinated against infectious canine hepatitis may develop ocular lesions. What are these ocular lesions and what is their pathogenesis?
Infectious canine hepatitis, caused by canine adenovirus type 1 (CAV-1) is associated with development of “blue-eye”, in which the cornea becomes edematous and opaque. Infection or vaccination with CAV-1 can result in immune complex uveitis, a type III hypersensitivity reaction
Compare and contrast the appearance and causes of (1) nodular hyperplasia and (b) nodular regeneration in the liver of dogs
(1) Nodular hyperplasia: usually solitary, well demarcated, smoothly domed and NOT associated with hepatic disease (neither causing nor resulting from it); (2) Nodular regeneration: the liver is small, firm and irregular with nodules of regenerative parenchyma separated by tracts of fibrous connective tissue. This disease is the result of prolonged insult to the liver, such as that caused by chronic anticonvulsant administration.
You are performing a necropsy on a foal and find disseminated abscesses throughout the mesenteric lymph nodes, spleen, liver and large intestine. What is the most likely cause?
Rhodococcus equi
Name the organism that causes Tyzzer’s disease.
Clostridium piliforme
Which pattern of hepatic necrosis (centrilobular or periportal) is more likely in cases of anemia or hypoxia and why?
Centrilobular. Hepatocytes in Zone 3 of the lobule (centrilobular; closest to central veins) are the last to receive blood and, therefore, may be the first to be injured by ischemia -> CENTRILOBULAR NECROSIS
What lifecycle stage of the harmless Taenia tapeworms found in wild and domestic canids is found in intermediate hosts, and where in the intermediate host are these found??
The encysted intermediate stages of Taenia tapeworms are called Cysticercus. They are found in solid organs (often liver) of the intermediate hosts: horses, ruminants, pigs, rabbits, rodents etc.
What organism causes hydatid cysts in sheep and aberrantly infected humans?
Echinococcus spp. These are tapeworms in canids that, when ingested in feces, cause formation of large cysts in the solid organs of the intermediate host. These cysts can be fatal in humans.
Theiler’s disease in horses results from (a) Clostridium piliforme infection or (b) recent injection of a biologic that contains equine serum (e.g., tetanus antitoxin). [Choose one answer]
(b) Recent injection of a biologic that contains equine serum (e.g., tetanus antitoxin)
You are examining the liver of a cow and find several encysted parasitic cysts, later identified as Cysticercus species. How was this cow infected? What is the lifecycle of this parasite?
From grazing on pasture contaminated by the feces of a canid infected with the tapeworm species Taenia. The lifecycle is completed when the canid eats the cyst in the intermediate host (i.e., the cow).
Where, precisely, are hepatic Ito (stellate) cells found within the liver?
In the space of Disse
How does lack of iron supplementation result in liver disease in young, indoor-housed pet pigs?
Iron deficiency -> anemia -> ischemic injury to centrilobular hepatocytes -> centrilobular necrosis -> icterus
Which pattern of hepatic necrosis (centrilobular or periportal) is more likely in cases of hepatotoxicity and why?
Periportal. Hepatocytes in Zone 1 of theliver lobule (periportal; closest to portal areas) are the first to receive blood and, therefore, may be the first to be injured by circulating toxins -> PERIPORTAL NECROSIS
You are examining the liver of a horse that died of hepatic failure. The liver is small, flabby and limp (“dishrag” appearance). What is the most likely disease, and what aspect of this horse’s history should be investigated?
Theiler’s disease. You should investigate whether this horse has had a recent injection of a biologic that contains equine serum (e.g., tetanus antitoxin)
Name 3 routes in which bacteria can reach the liver via the bloodstream.
- The portal vein; 2. The umbilical veins from umbilical infections in newborn animals; 3. The hepatic artery, as part of a generalized bacteremia.
Canine adenovirus type 1 (CAV-1), the cause of infectious canine hepatitis, has a tropism for which types of cells? Name three.
(1) Hepatocytes; (2) Endothelial cells; (3) Mesothelial cells, such as those lining the peritoneal, pleural and pericardial cavities
What is the name and appearance of a malignant liver mass derived from the cells that line biliary ductules?
Cholangiocellular carcinoma; Multiple, randomly distributed firm hepatic nodules, many with umbilicated centers
What is the term for the condition of gallstones?
Cholelithiasis
A thickened edematous gall bladder in a dog that died of systemic disease is characteristic of which disease, and what is the cause of this disease?
Infectious canine hepatitis, caused by canine adenovirus type 1 (CAV-1)
Mucocele of the gall bladder is seen most frequently in which domestic species?
Dogs
One cause of chronic hepatitis in dogs is copper accumulation. In one breed in particular there is a well-recognized genetic mutation that prevents copper excretion by hepatocytes. Name this breed.
Bedlington terrier
You are examining the carcass of an aborted calf and notice randomly distributed white “dit-dots” through the liver, kidneys, lungs and spleen. What is the most likely cause of these?
Abortion due to infection with bovine herpesvirus type 1 (BHV-1)
What is another name for equine serum hepatitis?
Theiler’s disease
You are performing a necropsy on a feedlot steer and find numerous foci of necrosis and abscess formation throughout the liver. What are the likely (a) cause and (b) pathogenesis?
(a) Fusobacterium necrophorum; (b) Damage to ruminal mucosa (rumenitis) -> bacteria enter portal circulation -> shower liver -> hepatic abscesses -> poor production
Why are humans so concerned about infection of pet dogs and wild canids (e.g., coyotes) with the relatively harmless tapeworms in the genus Echinococcus?
Echinococcus spp. are tapeworms in canids that, when ingested in feces, cause formation of large cysts in the solid organs of the intermediate host. These cysts can be fatal in humans.
How is canine adenovirus type 1 (CAV-1), the cause of infectious canine hepatitis, transmitted among dogs?
Urine-oral infection
Cholecystitis (gall bladder inflammation) is seen most commonly in calves with which infectious disease?
Enteric salmonellosis
What does the term cholangiohepatitis mean?
Inflammation affecting both the biliary ducts and hepatic parenchyma
Cholecystitis (gall bladder inflammation) is seen most commonly in dogs with which infectious disease?
Infectious canine hepatitis, caused by canine adenovirus type 1 (CAV-1)
You are examining the liver of a cow and find numerous linear and branching dark black tracts throughout the parenchyma that appear to follow vessels. What is the most likely cause?
These are migration tracts of liver flukes (Fasciola hepatica), which live in and migrate along biliary ductules
Which hepatic disease is caused by Clostridium piliforme?
Tyzzer’s disease
True or false: infection with canine adenovirus-1 generally causes fulminant infection which is often fatal.
False; most infections are asymptomatic
What is one characteristic (and “non-lumpy”) appearance of a liver with infiltrative / metastatic lymphoma? How does this appearance arise?
Diffuse hepatic enlargement, pale liver and an enhanced lobular pattern that can mimic various other hepatic diseases. The reason for this is that neoplastic lymphocytes typically aggregate in portal areas of each lobule, rather than forming discrete nodules (although the latter is possible and even common; lymphoma does not follow rules and should always be considered in a differential list).
Name two clostridial species that may proliferate in the necrotic debris left by migrating hepatic flukes in ruminants.
C. haemolyticum –> bacillary hemoglobinuria (red water disease); C. novyi –> infectious necrotic hepatitis (black disease)
Name 3 NON-vascular routes by which bacteria may reach the liver.
- Ascending infection of the biliary system; 2. Parasitic migration; 3. Direct extension of an inflammatory process from tissues immediately adjacent to the liver, such as the reticulum.
What is the name and appearance of a malignant liver mass derived from hepatocytes?
Hepatocellular carcinoma; Poorly demarcated and multilobular mass that invades adjacent liver parenchyma. The centres of neoplastic lobules are frequently necrotic
What agent causes infectious canine hepatitis?
Canine adenovirus type 1 (CAV-1)
Tyzzer’s disease in horses results from (a) Clostridium piliforme infection or (b) recent injection of a biologic that contains equine serum (e.g., tetanus antitoxin). [Choose one answer]
(a) Clostridium piliforme infection
You perform a necropsy on a dog with no clinical signs and note that the gall bladder has a “sponge-like” consistency. What is this condition?
Cystic mucinous hyperplasia
Each species has its own abortigenic herpesvirus strain. What strain causes abortion in: (a) horses; (b) cattle; (c) dogs; (d) cats?
(a) EHV-1; (b) BHV-1; (c) CHV-1; (d) FHV-1
Iron deficiency is a risk in which particular population of pigs?
Young, indoor-housed pet pigs
What is the alternative name for a hepatic Ito cell?
Hepatic stellate cell