Obstructive Jaundice

Question 1

What are the 2 main signs of jaundice and why?

Answer 1

1. Yellow eyes
   
   • yellow sclera —> 1st sign
     - high in elastin —> high affinity for
     bilirubin
2. Yellow skin
   
   • over 2.5mg/dL serum bilirubin

+ pale stool, dark urine

Question 2

How is bilirubin produced?

Answer 2

Red blood cells die (120 days) —> phagocytosed in
reticuloendothelial system (spleen + lymph nodes):

Hb —> heme —> iron
—> protoporphyrin —> unconjugated
bilirubin
—> globin —> amino acids

Question 3

What is the difference between UCB and CB?

Answer 3

Unconjugated bilirubin:
- lipid-soluble —> not water-soluble —> binds to
albumin to be carried in blood (to hepatocytes for
conjugation)
- indirect bilirubin

Conjugated bilirubin:
- water-soluble
- via UGT (uridine glucuronyl transferase) in
hepatocytes
- secreted by liver to bile canaliculi —> bile ducts —>
gallbladder

Question 4

What are the 3 steps of bilirubin being excreted in faeces?

Answer 4

1. Food —> CB secreted by gallbladder —> small
   intestine
2. CB to UBG (urobilinogen) by intestinal microbes
3. UBG to stercobilin —> excreted in faeces

Question 5

What are the … steps of bilirubin being excreted in urine?

Answer 5

1. Food —> CB secreted by gallbladder —> small
   intestine
2. CB to UBG (urobilinogen) by intestinal microbes
3. UBG reabsorbed to blood —> UBG to urobilin via
   oxidation
4. Urobilin —> most to liver
   —> some to kidneys —> excreted in urine

Question 6

What are 5 causes of increased UCB?

Answer 6

1. Extravascular haemolytic anaemias
   
   • RBCs broken down too early
2. Ineffective haematopoiesis
   
   • RBCs not formed correctly —> broken down
3. Gilbert’s syndrome - genetic
   
   • low UGT
4. Crigler Najjar syndrome
   
   • no UGT
   • usually fatal ∵ UCB deposits in brain basal ganglia
     —> kernicterus
5. Newborn jaundice
   
   • lower UGT + fetal RBC destruction
   • treat: phototherapy (non-invasive)

Question 7

What are the … causes of increased CB?

Answer 7

1. Dubin-Johnson syndrome - genetic (auto rec)
   
   • MRP2 deficiency —> use MRCP3 —> transports CB
     to blood instead of bile canaliculus
2. Obstructive jaundice
   
   • bile flow blocked

Question 8

What is obstructive jaundice?

Answer 8

Blockage of bile/pancreatic duct causing jaundice

Question 9

What are … causes of obstructive jaundice?

Answer 9

1. Tumours - Hilar cholangiocarcinoma
   - Distal cholangiocarcinoma
   - Head of pancreas carcinoma
2. Cancers - Gallbladder
   - Duodenal
   - Ampullary
   - Malignant hilar lymphadenopathy
3. Diseases - Primary sclerosing cholangitis
   - Chronic pancreatitis
   - Hydatid cyst (helminth infection)
   - Mirizzi’s syndrome
4. Other - CBD stones (common bile duct)
   - Post cholecystectomy ischaemic CBD
   stricture

Question 10

What are 6 symptoms of obstructive jaundice?

Answer 10

1. Pruritis = itchy skin
   - bile contents deposit in skin
2. Hypercholesterolaemia - cholesterol in bile
3. Xanthomas = yellow patch on skin
   - lipid deposits in skin
4. Dark urine - excess urobilin through kidneys
5. Steatorrhea - lose bile —> can’t digests fats
6. Fat-soluble vit deficiencies - lose bile —> can’t
   digests fats

Question 11

What is a cause of increased UCB and CB?

Answer 11

Viral hepatitis:
Hepatocytes infected and die
—> less conjugation —> excess UCB
—> bile can leak out to blood —> excess CB

Question 12

Which 2 blood tests are used to diagnose obstructive jaundice?

Answer 12

1. Serum amylase
2. Prothrombin time

Question 13

Which 3 scans are done to diagnose obstructive jaundice?

Answer 13

1. US —> first
2. MRCP —> second
3. CT —> final (to exclude other cause)

Question 14

How are gallstones treated?

Answer 14

Laparoscopic cholecystectomy
= gallbladder removal (keyhole surgery)
- simultaneous CBD (common bile duct) exploration
- may discharge after ERCP —> book surgery later

Open cholecystectomy
- if keyhole surgery won’t work