C12 pt 2 Flashcards

1
Q

liver fibrosis involves activation of what cells?
- when reversible? permanent?

A

o Potentially reversible in acute, self-limiting injury
o In severe injury, cross-links and becomes resistant to degradation, leading to
permanent scarring
o In persistent injury, becomes progressive and can lead to cirrhosis
o Variety of possible patterns…

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2
Q

Fibrosis along the Space of Disse leads to

A

o Fibrosis along the Space of Disse leads to loss of endothelial fenestration
(capillarization) and impairs exchange between hepatocytes and blood
o Hypoxia leads to accompanying hepatocellular atrophy
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Dissecting fibrosis – worst prognosis

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3
Q

liver cirrhosis: when do we see it?

A

Cirrhosis: nodular regeneration, bridging fibrosis, vascular disruption, biliary hyperplasia
o Associated with hepatic insufficiency
o End result of multiple pathological processes
o Nodules have increased cellular mass but
less sinusoidal space
o Fibrosis contributes to portal hypertension
(ascites)
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* Nodules do not always mean cirrhosis!
o Dogs are the only species that tend to form
regenerative nodules

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4
Q

signs of liver dysfunction often manifest where?

A
  • Signs of dysfunction often manifest in other organs (brain, skin, gut)
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5
Q

acute liver failure
- is it common? causes?

A

Acute liver failure is uncommon and due to severe and rapid injury
o Usually toxins, sometimes hyperthermia or acute ischemia

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6
Q

Chronic liver failure subdivisions and what they are

A

Chronic liver failure is subdivided into end stage liver (failure due to progressive fibrosis and loss of functional mass) and acute-on-chronic (a compensated failing liver suddenly flips into acute failure)

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7
Q

Hepatic encephalopathy cause, signs, prognosis

A

o Ammonia toxicity is important (mostly derived from dietary protein, detoxified and removed by the liver)
o Ammonia crosses the blood-brain barrier, damages astrocytes and reduces brain metabolism
o Variable neurologic signs
§ Ruminants: blindness, dullness
§ Horses: mania
§ Dogs and cats: subtle (inappetence, vomiting)
o Can cause death due to cerebral edema
o Poor prognosis in acute disease, less negative indicator in chronic disease

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8
Q

Cholestasis - whats this? leads to? types?

A

Cholestasis: impaired bile secretion and/or flow
o Leads to increased bilirubin in the blood
o Can be hepatocellular (altered function) or obstructive

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9
Q

Jaundice
- what is it? where to look?

A

Jaundice: yellow pigmentation of tissues due to excess plasma bile pigments
o Most prominent in the sclerae
o Do not mistake carotenoids in fat for jaundice! (horses, channel island cows: look
for pigment in connective tissue of dermis and periosteum to confirm jaundice)

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10
Q

Cholestasis and jaundice
- cateogires of jaundice?
- cholestasis always associated with what?
- NO JAUNDICE in what type of cholestasis?

A

o Jaundice can be prehepatic (ex. hemolysis), hepatic (altered function), or posthepatic (ex. obstruction) in cause
o Cholestasis is always associated with ductular reaction; in later stages may develop concentric fibrosis around bile ducts
o NO JAUNDICE in focal cholestasis – unaffected regions are still working

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11
Q

Photosensitization - what is it
- primary?
- hepatogenous?

A

o Inflammation of skin (usually unpigmented) due to action of UV light on photodynamic compounds bound to dermal cells

o Primary: the liver excretes unchanged native compounds that the animal ingested (ex. St. John’s wort)

o Hepatogenous: caused by cholestasis in herbivores eating green forages
> Plant porphyrins are catabolized to phytoporphyrins and normally excreted in
bile, but if retained they can cause photosensitization

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12
Q

Coagulopathy/hemorrhage
- more likely in what liver pahtology?
- will we see hemorrhage in chronic disease?

A

o Uncommon in acute liver failure, but more likely in acute liver necrosis
o Necrosis causes consumption of clotting factors in the necrotic areas
o In chronic disease, there is usually no hemorrhage due to reduced clotting
factor production unless there is increased pressure on the clotting cascade
o Ex. surgical procedures

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13
Q

Edema/ascites
- what is it, when do we see?

A

o Ascites is low protein fluid, can form in chronic liver failure but more commonly seen with venous congestion
o Reduced protein production by the liver can contribute but ascites mainly forms due to increased sinusoidal pressure

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14
Q

Hepatocutaneous syndrome
- what species? signs?

A

o Also called superficial necrolytic dermatitis (SND), mostly seen in dogs
o Erythema, crusting, exudate, ulceration and alopecia of the footpads, periocular/perioral region, anogenital region, pressure points

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15
Q

Congenital portosystemic shunt (PSS) - what is not connected properly?
- types?
- compare with acquired PSS?
- signs
- Tx

A

o Aberrant connection between the portal vein and vena cava (portocaval) or azygous vein (portoazygous)
o Can be extrahepatic or intrahepatic, most common in dogs and cats o Regardless of location, always a single vessel (compare with
acquired PSS later…)
o Clinical signs: failure to thrive, +/- hepatic encephalopathy
o Hypoplastic liver (not getting growth factors from the gut)
o No portal hypertension = no ascites
o Typically respond well to shunt ligation but not always

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16
Q

Extrahepatic portosystemic shunt (congenital)
- what may we see beyond the shunt?
- animals affected?

A

o May have portal hypoplasia beyond the shunt
o Small dogs, cats
o Hereditary in Maltese, Yorkie

17
Q

Intrahepatic portosystemic shunt (congenital)
- most common cause?
- breeds?

A

o Persistent patent ductus venosus
most common
o Large dogs (hereditary in wolfhound)

18
Q

liver should not extend where? what does it mean if it does?

A
  • Liver should not extend beyond the costal arch
    o If it does, indicates enlargement or pressure from thorax on the diaphragm
19
Q

All or part of the liver can end up in the thorax, subcutis, or pericardium due to:

A

hernias
* Congenital or acquired (trauma)

20
Q

liver Lobe torsion
- in what species?
- what lobe?
- secondary issues?

A

o Reported in rabbits (seem especially prone), pigs, dogs,
cats, horses
o Left lateral lobe most common, can affect others
o Hypoxia can allow secondary clostridial growth

21
Q

most common reason for liver rupture? predisposing factors?
- usual presentation?
- what animal age group most commonly?

A
  • Liver rupture is most commonly due to trauma
    o Predisposing factors: tumours, lipidosis, amyloid, etc
    o Subclinical unless large enough to cause exsanguination or damage bile ducts (leading to bile peritonitis)
    o More common in young animals (liver more friable than in adults)
22
Q

Portal hypertension
- types and causes
- effect if persistent

A

o Prehepatic: uncommon, usually thrombosis
o Hepatic: pre-sinusoidal, sinusoidal, or post-
sinusoidal
o Post-hepatic: uncommon, increased resistance
to flow in vena cava or heart
o Persistent portal hypertension leads to acquired portosystemic shunts, ascites

23
Q

Acquired portosystemic shunts
o Can develop due to anything that causes:
- origins?
- PM considerations?

A

Acquired portosystemic shunts
o Can develop due to anything that causes
portal hypertension
o Originate from vestigial communications that dilate to relieve pressure
o Multiple, small, tortuous, thin-walled vessels o MUST LOCATE BEFORE REMOVING
ABDOMINAL VISCERA!

24
Q

Passive congestion of liver
- causes
- gross appearance

A

o Pressure in the hepatic veins increases relative to portal pressure
o Usually due to cardiac dysfunction, producing acute sinusoid congestion when
there is sudden decompensation or shock
o Gross: liver slightly larger, red, may have enhanced zonal pattern (nutmeg liver)
o Blood flows freely from the cut surface
o Chronic cases: increased fibrous tissue, ascites
o Over time fibrosis links the centrilobular areas (cardiac fibrosis pattern)

25
Q

Omphalitis
- how does it affect the liver?

A

o The umbilical vein drains to the left lobe,
so abscesses usually form here
o Spread is physical – no blood flow after
birth!

26
Q

Peliosis hepatis/telangiectasis
- what are these?
- cause?
- appearance?
- what animals?

A

o Cystic, blood-filled spaces in the liver
o Due to loss of cells or weakness in
connective tissue
o Well circumscribed, irregular, dark red foci
o Often depressed, drain blood when cut
o Older cats and cattle

27
Q

are fatal liver tumours common in dogs and cats?

A

no

28
Q

Nodular hyperplasia
- common in what species?
- associated with?
- appearance
- significance

A

Nodular hyperplasia: common in dogs, rare in other species
o Presence of nodules in otherwise normal livers increases with age
o Well circumscribed, often multiple, look similar to normal tissue
o Usually no clinical significance

29
Q

Gallbladder mucocele
- what
- animals
- possible sequelae

A

Gallbladder mucocele: dilation with mucoid secretion
o Mostly seen in dogs but can affect cats, etiology unknown
o May cause necrosis and rupture

30
Q

hepatocellular vs biliary tumors
- how common in dogs vs cats?

A

o Dogs hepatocellular > biliary
VS
o cats biliary > hepatocellular

31
Q

Hepatocellular adenoma
- appearance
- significance

A

o Usually single, spherical, well demarcated, and not clinically significant

32
Q

Hepatocellular carcinoma
- appearance
- possible developments?

A

o Poorly demarcated
o May be single, nodular, or diffuse
o Commonly invade veins
o Metastasis uncommon but possible
o Prone to rupture and can cause fatal hemorrhage

33
Q

Cholangiocarcinoma
- appearance
- possible developments

A

o Pale, often umbilicated, almost always multiple or diffuse
o Very invasive, commonly metastasize to lymph nodes and lungs
o May cause carcinomatosis (especially in cats)
o May resemble metastases of other carcinomas (mammary, pancreatic, etc)

34
Q

is the liver a common spot for metasteses? why?

A
  • Almost anything can metastasize to liver (because of its blood supply)
    o Lymphoma, hemangiosarcoma, pancreatic carcinoma most common in dogs
    o Also mammary carcinoma, thyroid carcinoma, melanoma,
    carcinomatosis, histiocytic sarcoma, etc. etc…