Pathology of the Hepatobiliary System #3 Flashcards
List the reactions of the liver to injury.
- Intracellular accumulation
* Glycogen accumulation
* Fatty change / lipidosis
* Bile stasis
* Amyloidosis - Cell degeneration and death: apoptosis, necrosis
- Inflammation
- Cirrhosis
* Regeneration, fibrosis, and ductular reaction (biliary hyperplasia)
Hepatocytes may be killed by a variety of insults:
- Hypoxia: focal area of infarct –> hypoxia –> infarct.
- Toxins: e.g. Central lobular most impacted, alcohol –> cirrhosis –> apoptosis
- Microorganisms: infectious disease e.g. milliary hepatitis will occur in case of microorg infection.
- Immunological events / inflammation
- Severe metabolic disturbances: e.g. too much ammonia
- Trauma: HBC –> liver rupture
What are the patterns of necrosis? Explain each.
What can be seen in this image below?
This pig suffered from Hepatosis dietetica.
This is an example of ACUTE Massive (Panlobular) Necrosis
* Cause: deficiency of vitamin E and/or selenium.
What can be seen in this image below?
Zonal Necrosis
* This horse suffered from zonal necrosis; most commonly centrilobular necrosis
* Caused by hypoxia
Enhanced zonal pattern of hepatocellular necrosis in a horse
What can be seen in the image below?
Multifocal Random Necrosis
* Caused by many infectious agents, including viruses, bacteria, and certain protozoa
Random hepatocellular necrosis caused by equine herpesvirus infection in a foal
EHV-1 causes this; abortion of fetus
What can be seen in the image below?
Sequelae to Hepatic Injury
Cirrhosis (“End-stage liver”)
Multifocal nodules affecting liver; liver is very small, and these nodules are representative of regeneration b/c liver is trying to repair itself
As much as ____% of the normal liver can be removed surgically ________ clinical insufficiency, and in the course of a few weeks, it is back to its _______ mass.
As much as 70% of the normal liver can be removed surgically without clinical insufficiency, and in the course of a few weeks, it is back to its normal mass.
What happens during the process of hepatic regeneration?
In regeneration
* Hepatocellular loss is replaced by proliferation of mature hepatocytes or
biliary epithelium, bipotential progenitor cells (ductular reaction; biliary
hyperplasia).
* Endothelial buds establish sinusoidal channels
* Hepatic stellate cells replicate and synthesize extracellular matrix
Describe the process in which the liver can regenerate itself.
If you damaged the reticulin framework, there is no way you can regenerate your liver.
Cirrhosis is loss of hepatic _________, ________ regeneration, _______ fibrosis, biliary ______.
Loss of hepatic parenchyma, nodular regeneration, bridging fibrosis, biliary
hyperplasia
What is the consequence of cirrhosis in dogs?
Consequence in dogs: Acquired portosystemic shunts (sinusoids are bypassed)
* Liver injury → Hepatic fibrosis → portal hypertension → acquired portosystemic shunts →
nutrients are not received → increased hydrostatic pressured → ascites (due to loss or protein, hydrostatic pressure).
What is the difference between nodular regeneration and nodular hyperplasia?
Do not confuse nodular regeneration with nodular hyperplasia.
* Nodular regeneration is in response to loss of hepatocytes.
* Nodular hyperplasia is a common incidental finding in older dogs.
List the causes of Cirrhosis.
- Chronic toxicity (therapeutic agents or naturally occurring toxins)
- Chronic cholangitis and/or obstruction
- Chronic congestion (right-sided heart failure) [nutmeg liver]
- Inherited disorders of metal metabolism (copper or iron)
- Chronic hepatitis
- Idiopathic
End-Stage Liver (Cirrhosis), Dog
Not helpful to biopsy the parts of the liver that are not nodular b/c if you biopsy the nodules it won’t be helpful. Also avoid fibrosis.
End-Stage, Liver, Dog.
n: regenerative nodule
don’t see normal hepatic parenchyma
stringy material = fibrosis
Normal hepatocytes but they are dissociated. More blue cells = biliary epithelium. Should not be randomly arranged.
Acute passive congestion of the liver in a dog due to heart failure
Back up of fluid –> hepatic congestion
Chronic Passive Congestion (“Nutmeg Liver”), Liver, Cow
Reticular pattern looks like giraffe (white with black intermingled).
Subcutaneous edema due to congestive heart failure in a cow
Brisket disease
A. Normal
- PV enters sinusoid, blood goes into circulation via central vein, then vena cava.
B.
- Connection between two larger caliber vessels so it bypasses sinuoids –> hepatic atropy b/c liver does not get nutrients due to bypassing
C.
- Connection of PV directly into other veins either caudal vena cava, etc. but there is not much blood entering liver.
If proteins you eat are not metabolized, they accumulate and cause this.
Hepatic Lobar Torsion
* Trauma or idiopathic
Hepatic rupture with hemorrhage, Dog.
Usually see fissures on the liver
Amyloidosis with hepatic rupture and hemorrhage, Non-human primate.
