Usera: Liver 1 Flashcards

(54 cards)

1
Q

Describe the blood supply to the liver

A

portal vein: venous blood rich in nutrients from the alimentary tract
hepatic artery: arterial blood rich in oxygen from the celiac axis
hepatic veins: right drains the right lobe, left drains the left lateral lobe, middle drains the middle of the left lobe & some of the right lobe

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2
Q

What is included in the portal triad?

A

portal vein
bile duct
hepatic artery

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3
Q

Describe the structural unit of the liver

A

the lobule is a hexagonal unit that is oriented around a hepatic vein with portal tracts at the periphery
centrilobular = area closest to the hepatic vein
periorbital = area closest to the portal tract

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4
Q

Describe the acinus model with zones 1-3, which describes the physiologic relationship of hepatocytes & the blood supple

A

The acinus is a triangular unit, with the apex near the hepatic vein & the base formed by the vessels of the portal tract
Zone 1 is closest to the portal tracts, while zone 3 is closest to the hepatic vein

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5
Q

T/F: Liver disease is an insidious process in which clinical detection and symptoms of hepatic decompensation may occur weeks, months or many years after the onset of injury

A

True

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6
Q

What are three liver tests used to assess hepatocyte integrity?

A

AST
ALT
lactate dehydrogenase (LDH)

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7
Q

What are some liver tests used to assess biliary excretory function?

A

serum bilirubin (total & direct)
urine bilirubin
alkaline phosphatase

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8
Q

What are some liver tests used to assess hepatocyte function?

A

albumin
prothrombin time
ammonia

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9
Q

The most severe clinical consequence of liver disease

Results from loss of 80-90% of hepatic functional capacity

A

hepatic failure

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10
Q

What are the 3 categories of liver failure?

A

acute liver failure
chronic liver disease
hepatic dysfunction w/o overt necrosis

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11
Q

Hepatic necrosis and inflammation are present for at least 6 months
Most common route with the endpoint of cirrhosis

A

chronic liver disease

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12
Q

Viable hepatocytes with an inability to perform metabolic function
Tetracycline toxicity, acute fatty liver of pregnancy

A

hepatic dysfunction w/o overt necrosis

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13
Q

Liver disease associated with encephalopathy within 6 months after diagnosis

A

acute liver failure

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14
Q

Encephalopathy that develops within 2 weeks of jaundice

A

fulminant liver failure

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15
Q

Encephalopathy that develops within 3 months of jaundice

A

sub-fulminant liver failure

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16
Q

What drugs can cause acute liver failure?

A
acetaminophen
rifampin
isoniazid
MAOIs
halothane
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17
Q

What toxins can cause acute liver failure? What about infections?

A

carbon tetrachloride or mushroom poisoning

hep A and B

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18
Q

What are the clinical signs of hepatic dysfunction?

A
jaundice
easy bruising
hypoalbuminemia
hyperammonemia
hypoglycemia
fetor hepatis
hyperestrinism: hypogonadism, gynecomastia, spider angiomas, palmar erythema, muscle wasting (shoulder girdle atrophy)
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19
Q
What are these symptoms collectively known as? What are they clinical signs of?
Hypogonadism
gynecomastia
Spider angiomas
Palmar erythema
Muscle wasting (shoulder girdle atrophy)
A

hyperestrinism; signs of hepatic dysfunction

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20
Q

What are some complications of hepatic dysfunction?

A

hepatic failure: severe coagulopathy (can’t clot), encephalopathy, hepatorenal syndrome, multiple organ failure

portal hypertension: esophageal varices (abnormally enlarged veins in the lower esophagus - highly associated w/ liver failure)

malignancy

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21
Q

Disorder of neurotransmission in the CNS and neuromuscular system associated with elevated levels of ammonia
Spectrum of disturbances of consciousness
Subtle behavioral disturbances to confusion, stupor, coma and death

A

hepatic encephalopathy

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22
Q

What are the neurological signs of hepatic encephalopathy?

A

rigidity
hyper-reflexia
asterixis (flapping tremor)

23
Q

Renal failure in patients with severe chronic liver disease with no intrinsic cause for renal failure
Due to
Systemic vasodilation and decreased perfusion pressure
Activation of the renal sympathetic nervous system from vasoconstriction of afferent arterioles
Synthesis of renal vasoactive mediators

A

hepatorenal syndrome

24
Q

Common end stage to many underlying diseases
Fibrosis
Vascular disruption results in hypoperfusion
Nodular regeneration
Parenchymal/functional disruption

25
What is the most common cause of cirrhosis of the liver?
alcoholic liver disease
26
What happens to hepatic stellate cells, which usu store Vit A, in response to inflammation or toxin exposure?
they transform into myofibroblasts & deposit collagen leading to fibrosis
27
What are 3 morphologic characteristics of cirrhosis?
bridging fibrosis: deposition of collagen (types 1 & 3) due to activation of stellate cells into myofibroblasts parenchymal nodule formation: after injury, hepatocytes regenerate as spherical nodules w/i the fibrous septa architectural distortion: diffuse parenchymal injury & fibrosis
28
An increase in pressure in the portal vein due to arterial pressures being imposed on the portal system
portal hypertension
29
What are some prehepatic causes of portal hypertension?
obstructive thrombosis massive splenomegaly portal vein constriction
30
What are some intrahepatic causes of portal hypertension?
cirrhosis schistosomiasis massive fatty change diffuse granulomatous disease
31
What are some posthepatic causes of portal hypertension?
Right sided heart failure Constrictive pericarditis Hepatic vein outflow obstruction
32
What are the two main factors in portal hypertension?
increased resistance at the level of the sinusoids & increased flow
33
What causes the increased resistance in portal hypertension?
disruption of blood flow by scarring & formation of parenchymal nodules
34
What causes the increased flow in portal hypertension?
arteries vasodilate in the splanchnic circulation, leading to increased venous efflux in the portal system
35
Complication of portal hypertension involving accumulation of serous fluid in the peritoneal cavity
ascites
36
What are some porto-systemic shunts (bypasses) that can emerge as a result of portal hypertension? Why do these develop?
esophageal varices rectum --> hemorrhoids falciform ligament & umbilicus --> caput medusae **The rise in the portal system pressure leads to reversal of blood flow (portal to systemic) by dilation of collateral vessels and development of new vessels
37
What are the differences b/w unconjugated & conjugated bilirubin?
unconjugated: insoluble in water, tight complex with albumin in serum, cannot be excreted in urine conjugated: water soluble, non-toxic, loosely bound to albumin, excess can be excreted in urine
38
What is jaundice?
occurs when bilirubin production exceeds hepatic clearance
39
What are some ways in which you can have an elevated unconjugated bilirubin?
overproduction - hemolysis defective uptake - Gilbert's syndrome impaired conjugation - neonatal jaundice, or Crigler-Najjar types 1 & 2
40
What is Crigler Najjar syndrome? Which form is more severe, type 1 or 2?
very rare inherited disorder in which bilirubin cannot be broken down 1 is AR & severe 2 is AD & less severe
41
What are some causes of conjugated hyperbilirubinemia?
Rotor syndrome Dubin-Johnson syndrome - defective secretion, absence of MRP-2 **Dubin-Johnson syndrome is an inherited, relapsing, benign disorder of bilirubin metabolism. This rare autosomal recessive condition is characterized by conjugated hyperbilirubinemia
42
What is Dubin-Johnson syndrome?
an inherited, relapsing, benign disorder of bilirubin metabolism due to absence of MRP-2
43
What are two forms of neonatal jaundice?
physiologic jaundice: due to immature hepatic function & excretion system breast milk jaundice: bilirubin deconjugating enzymes in breast milk
44
Autosomal recessive disorder due to absent UGT1A1 Characterized by unconjucated hyperbilirubinemia Fatal in neonatal period
Crigler-Najjar type 1
45
Autosomal dominant disorder due to decreased UGT1A1 activity Characterized by unconjugated bilirubinemia Mild symptoms
Crigler-Najjar type 2 or Gilbert syndrome
46
Autosomal recessive disorder due to mutation in MRP2, leading to impaired excretion of bilirubin glucuronides Characterized by conjugated hyperbilirubinemia
Dubin-Johnson syndrome
47
Autosomal recessive disorder due to decreased hepatic uptake & storage Leads to conjugated hyperbilirubinemia
Rotor syndrome
48
Pathologic condition of impaired bile formation and bile flow that leads to the accumulation of bile pigment in hepatic parenchyma
cholestasis
49
What causes cholestasis?
Obstruction of bile channels | Defection in bile secretion
50
Signs & symptoms of cholestasis?
``` jaundice pruritis xanthomas silver stool elevated alkaline phosphate intestinal malabsorption ```
51
Prolonged conjugated hyperbilrubinemia | Not a specific entity or necessarily inflammatory
neonatal cholestasis
52
What are some causes of neonatal cholestasis?
``` Bile duct obstruction Neonatal infection Toxic Metabolic disease Idiopathic neonatal hepatitis ```
53
What are some parasitic disease of the liver?
``` echinococcal (hydatid) cyst clonorchis sinensis fasciola hepatica schistosomiasis malaria strongyloides ```
54
T/F: You can also get bacterial or amoebic abscesses in the liver
True