Patients_Liver & Biliary

Question 1

7 α-Hydroxylase - function?

Answer 1

Breaks down cholesterol during synthesis of Bile

Question 2

Where is fat absorbed?

Answer 2

Ileum

Question 3

3 enzymes necessary for fat absorption/

Answer 3

• Lipase (pancreas)
• Bile salts (gall bladder)
• Enterocytes

Question 4

Bile salt synthesis includes conjugation w/ what 2 amino acids?

Answer 4

Taurine & Glycine

Question 5

What is the rate-limiting step of bilirubin conjugation?

Answer 5

The transfer of conjugated bilirubin from the hepatocyte into the cannaliculi

Question 6

Is Bilirubinuria due to conjugated or unconjugated bilirubin in the urine?

Answer 6

Conjugated (always)

(b/c unconjugated bilirubin is attached to albumin & this is too large to be excreted by kidneys)

**this is always pathologic

Question 7

Is it ever normal for bilirubin to be in the urine?

Answer 7

No, this is always pathologic & due to massive hepatic injury (conjugated bilirubin released into blood upon hepatic injury)

(urobilinogen should be in urine, not bilirubin)

Question 8

What is the molecular marker for Hepatocellular Carcinoma (HCC)?

Answer 8

α-fetoprotein (AFP)

Question 9

Which labs are the markers of true “liver function?”

Answer 9

• Albumin
• Ammonia (converted → urea; this is more a test of liver failure)
• Prothrombin time
• Bilirubin (conjugation - both types)

Question 10

Which labs are the markers of “structural integrity” of the liver?

Answer 10

• AST (more specific for alcoholic injury b/c produced in mitochondria as well as cytosol)
• ALT (more specific to liver, b/c AST will also increase in muscle damage, hemolysis)

Question 11

Since Alkaline Phosphatase is synthesized in the liver & bones, what test distinguishes the source of an elevated Alk Phos?

Answer 11

γ-Glutamyl Transferase (GGT) indicates liver

Question 12

Upon hemolysis, what is the carrying protein that binds to hemoglobin?

Answer 12

Haptoglobin

so levels are low in patients w/ hemolysis

Question 13

What is Gilbert Syndrome?

Answer 13

Transient reduction in UDP-glucuronyl transferase activity

Question 14

What is the black substance that builds up in the liver in Dubin Johnson Syndrome?

Answer 14

Polymers of epinephrine metabolites

Question 15

Does an elevated Alkaline Phosphatase suggest Hepatocellular damage or Cholestasis?

Answer 15

Cholestasis

post-hepatic injury

Question 16

A patient presents to the ER with right upper quadrant colicky pain and fever. They are most concerned that the patient has acute cholecystitis. Which of the following tests is most helpful in establishing acute cholecystitis as the cause of this patient’s complaints?

1. Opacities in the right subcostal area on AXR
2. Increased serum AST and ALT
3. Failed gallbladder visualization on radionuclide biliary scan
4. Highly reflective structures inside the gallbladder on U/S
5. Distended duodenum on upper GI series

Answer 16

3. Failed gallbladder visualization on radionuclide biliary scan

Question 17

What Paraneoplastic properties does Hepatocellular Carcinoma (HCC) sometimes possess?

Answer 17

• Erythropoietin (↑HCT)
• PTH-rP (hypercalcemia)
• Hypoglycemia

Question 18

Primary Biliary Cirrhosis – Cause?

Answer 18

Autoimmune destruction of intrahepatic bile ducts

Question 19

What other diseases is Primary Biliary Cirrhosis related to?

Answer 19

Sjogren’s Syndrome

Question 20

Primary Biliary Obstruction – what effect may this have on eyesight?

Answer 20

Worse night vision due to ↓vitamin A

REMEMBER: Biliary obstruction causes ↓ fat-soluble vitamin uptake

Question 21

Which of the following mechanisms contribute most greatly to hepatocellular injury and centrilobular necrosis seen in acetaminophen toxicity?

1. Glutathione Depletion
2. Excessive Glucuronide Conjugation
3. Excessive Sulfation
4. Alcohol Dehydrogenase Depletion

Answer 21

1. Glutathione Depletion

(Glutathione normally stabilizes NAPQI, which is formed by hydroxylation of Glucuronic acid & Sulfate. An overload in NAPQI formation can damage hepatocytes)

Question 22

Acetaminophen toxicity primarily affects which Zone of the liver lobules?

Answer 22

Zone 3

Centrilobular Necrosis