Obstructive Jaundice Flashcards

1
Q

How is bile produced?

A

haem catabolism
uridine diphosphate glucuronyltransferase conjugates bilirubin –> bilirubin glucuronide –> secreted into bile

hepatocytes generate primary bile in canaliculi
= conjugated bilirubin + bile salts + cholesterol + phospholipids + proteins + ions + water

cholangiocytes modify canaliculi bile –> dilute and alkalinise bile

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2
Q

What does bile consist of?

A
water
Na+, K+, Ca2+
HCO3- (slightly higher than plasma)
Cl- (slightly lower than plasma)
lipids
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3
Q

How is bile excreted?

A

cholecystokinin stimulates the gallbladder and common bile duct to contract
secretin stimulates biliary duct cells to secrete bicarbonate + water –> increase bile volume –> increases flow into the intestine

~620mL/day - lowest during fasting
95% of bile salts will be reabsorbed

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4
Q

How is haem made into conjugated bilirubin?

A

haem – (haem oxygenase) –> biliverdin – (biliverdin reductase) –> bilirubin –> glucaronic acid attached by uridine diphosphate glucoronyltransferase (UGT) –> urobilinogen
to be excreted via feaces and urine

unconjugated bilirubin is attached to albumin
detached when it meets the sinusoidal surface of the liver
diffuses through hepatocytes to be conjugated

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5
Q

What are the main types of jaundice? Give examples.

A

Haemolytic - drugs, inherited disorder eg SCD

Hepatic - cirrhosis, hepatitis

Obstructive/Cholestatic - CBD stones, pancreatic cancer

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6
Q

What are some RFs for jaundice?

A
excess alcohol use
IV drug use
occupational history
travel history
sexual activity
pregnancy
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7
Q

How can you tell the difference between pre/hepatic and obstructive jaundice?

A

pre/hepatic - dark urine, slightly pale stool, v raised ALT, raised ALP, AST, splenomegaly

obstructive - dark urine, pale stool, v raised ALP, AST, raised ALT, no splenomegaly

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8
Q

What blood tests can be performed to determine the cause of jaundice?

A
LFTs
Bilirubin
PT + INR 
FBC
Aminotransferase
IgG4
Viral hepatitis serology
Copper concentration
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