Liver Function Flashcards

1
Q

What is the role of the liver?

A

Key roles included excretion and secretion, synthesis, and detoxification and drug metabolism.
-Other functions include metabolic function, and storage.

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2
Q

What enzymes are used to assess liver function?

A
  • ALT
  • AST
  • ALKP
  • GGT
  • 5’ Nucleotidase
  • LDH
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3
Q

Which two enzymes rise together in liver disorders?

A
  • AST/ALT – Rise rapidly in liver disorders. Remain elevated in chronic conditions.
  • Both will be low when liver cells are destroyed ( liver failure ).
  • Both normal or slightly elevated in obstruction
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4
Q

Where is ALT found and what is it sensitive to?

A

Found in hepatocytes – specific to liver

More sensitive in viral induced hepatocellular damage

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5
Q

Which stays elevated longer, AST or ALT?

A

ALT

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6
Q

What is ALT>AST indicative of?

A

ALT>AST – hepatitis, most liver disease

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7
Q

Where is AST found and what causes it to increase?

A

Found in many sources. Many things can cause it to increase

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8
Q

What is AST>ALT indicative of?

A

AST>ALT – cirrhosis

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9
Q

What do AST values higher than 400 suggest?

A

Acute viral hepatitis

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10
Q

Where is ALKP found?

A

many sources of the body

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11
Q

What is ALKP useful to distinguish?

A

Useful to differentiate obstruction from Hepatocellular injury

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12
Q

What do high ALKP values suggest?

A

Highest amounts found in obstruction

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13
Q

What do mild ALKP values suggest?

A

Mild elevation in cirrhosis or hepatitis

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14
Q

What is GGT and where is it found?

A

Membrane enzyme that helps amino acid cross cell membrane

-Found in liver cells and bile duct walls

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15
Q

What is GGT a sensitive marker for?

A

Makes it sensitive marker for obstructive cholestasis and ETOH ingestion – highest values seen in these cases

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16
Q

How is GGT used to help determine where high ALKP values come from?

A

Can help differentiate cause of increased ALKP. If ALKP is high and GGT is normal – probably not liver
When liver cells are destroyed, values will be decreased

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17
Q

Where is LDH found?

A

Widely distributed in the body.
high amounts in RBCs
LDH is increased as RBCs turnover

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18
Q

What can LDH be used to differentiate the cause of?

A

the cause of increased ALKP

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19
Q

What does moderate LDH increase suggest?

A

hepatobiliary disease

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20
Q

What does a slight LDH elevation suggest?

A

biliary tract disease

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21
Q

What does a high LDH elevation suggest?

A

hepatic carcinoma

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22
Q

Where is 5’ nucleotidase found?

A

widely distributed in the cells

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23
Q

What can 5’ nucleotidase help differentiate?

A

elevated ALKP

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24
Q

What 2 enzymes will be elevated in liver disease?

A

5’ nucleotidase and ALKP

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25
Q

What one enzyme will be elevated in bone disease?

A

ALKP

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26
Q

What does a significant elevation of 5’ nucleotidase suggest?

A

hepatobiliary disease

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27
Q

What usually happens to ammonia and what can changes in ammonia reflect?

A
  • Normally converted to urea by liver and excreted

- Reflects the liver’s ability to convert ammonia to urea

28
Q

In what conditions will ammonia be increased?

A

Will be increased in liver failure and can lead to hepatic coma, also in Reye Syndrome

29
Q

What methods are used to assess ammonia?

A

Caraway, Nessler’s and Enzymatic reaction

30
Q

What are normal and critical values of ammonia?

A

Normal 20-50 umol/l. greater than 100 is critical

31
Q

Where is albumin synthesized and what can it help measure?

A

Synthesized in liver – liver problem will result in decreased synthesis

32
Q

What type of disease is decreased albumin usually found in?

A

Decrease found more in chronic disease

33
Q

When are IgG and IgM both increased?

A

chronic active hepatitis

34
Q

When is just IgM elevated (Liver)

A

in primary biliary cirrhosis

35
Q

What liver problem will just IgA be increased?

A

alcoholic cirrohosis

36
Q

Why would PT be increased in liver disease?

A

The clotting factors are synthesized in the liver

37
Q

What is a common tumor marker and may be used to see cancer in the liver?

A

AFP-hepatic carcinoma

38
Q

What are the general characteristics of unconjugated bilirubin?

A

Bound to albumin – insoluble in water, is not filtered and excreted by kidney

39
Q

What are the general characteristics of conjugated bilirubin?

A

Is now soluble in water and can be filtered and excreted

40
Q

What is delta bilirubin and how does it occur?

A

conjugated bili that is bound to albumin. Can occur when liver is conjugating effectively but it cannot be excreted from the liver. Is a problem because it is measured as conjugated in lab testing

41
Q

when is delta bilirubin generally seen?

A

Results will not add up. Only seen in significant obstruction

42
Q

Where is urobilinogen created ?

A

Derived from Bilirubin in GI tract. Oxidized by intestinal bacteria to form urobilin. Adds color to stool.

43
Q

When is urobilinogen seen in disease and when is it absent?

A
  • Absent in obstruction

- Increased in hemolytic disease, defective liver cell function, hepatitis

44
Q

When is hepatomegally generally seen?

A

Seen primary or secondary to liver disease.

45
Q

What is ascites fluid?

A

Presence of free fluid in the peritoneal cavity

46
Q

When is ascites fluid generally seen?

A

Commonly seen in cirrhosis due to alcoholism
Hepatitis
Hepatic vein obstruction

47
Q

What is kernicterus?

A

Bilirubin deposited in nuclei of brain and nerve cells. Is life threatening. May require exchange transfusion

48
Q

What are signs of prehepatic jaundice?

A

Total Bili rarely exceed 5 mg/dL
Bilirubin will not be seen in a UA
Urobilinogen in seen in urine as result of increased bili being conjugated
Stool will be dark brown due to increase in conjugated bili being broken down

49
Q

What are the common diseases of biliary metabolism?

A

Gilberts syndrome
Criggler-Najjar syndrome
Neonatal jaundice

50
Q

What will you see an increase in if you have a biliary disorder?

A

Results in increase in unconjugated bili

51
Q

What are some common disorders of biliary transport?

A

Dubin-Johnson syndrome
Rotors syndrome
other intra or extrahepatic obstruction

52
Q

What will you see an increase in if you have a biliary transport disorder?

A

See increase in conjugated bilirubin

53
Q

What is Gilbert disease and what does it effect?

A
  • inherited disease affecting 5% of population – No morbidity or mortality
  • Increase in Bu absent of hemolysis or other disease affecting bili conjugation
  • Occurs in adolesence or early adulthood
  • Problem is with encoding of enzyme that catalyzes bilirubin conjugation
54
Q

Which diseases are Unconjugated Hyperbilirubinemia

diseases?

A

Gilbert disease
Criggler Najjar
neonatal jaundice

55
Q

Which diseases are Conjugated Hyperbilirubinemia

diseases?

A

dubin-johnson syndrome

rotor syndome

56
Q

What is dubin-johnson syndrome and what does it cause?

A

rare inherited disorder causing a deficiency in a transport protein
Liver can uptake and conjugate bilirubin properly, problem is in transporting it out of cells to be excreted in Bile
The conjugated Bili can back-up into blood and bind with albumin ( delta bilirubin )
Mild in nature – normal life expectancy
Characterisitic dark staining granules seen on liver biopsy

57
Q

What are the signs of posthepatic jaundice?

A

Bile is not presented to intestines
No urobilonogen
Stool - no color
Urine – No urobilinogen

58
Q

What things should you avoid when taking a bilirubin sample?

A

Protect from light
Avoid hemolysis
Icteric sample

59
Q

What is Ehrlich’s method and how is it done?

A

original method for bili determination
Done on urine
Bili reacts with Diazotized Sulfanilic Acid to form a color
Diazo reaction

60
Q

What is the van den bergh method?

A

Modified this in early 1900 to use on serum
Addition of an accelerator or solubilizer – Bu not soluble in water
Method had errors

61
Q

What is cholestasis?

A

Stoppage of bile flow. Commonly due to bile duct obstruction

62
Q

What is cirrhosis and what are common causes?

A

Normal, healthy tissue is replaced by scar tissue
Liver unable to function. Scar tissue disrupts blood flow through the organ
Most common causes – Alcohol abuse, Hep C infection

63
Q

What is hepatitis?

A

Inflammation of liver tissue
Caused by bacteria, virus or parasite in addition to autoimmune disorders, radiation or drugs
Most hepatitis is viral in nature

64
Q

What is the most useful hepatitis marker and why?

A

HbsAG
can detect before symptoms occur
allows for early treatment

65
Q

What can be used to differentiate active, chronic or resolving infection when used with other tests in hepatitis cases?

A

Hbcore AB