Jaundice

Question 1

What is jaundice?

Answer 1

Yellowing of the skin, sclerae, and mucosae from increased plasma bilirubin (visible >60umol/L).

Question 2

How is jaundice classified?

Answer 2

1. Site - prehepatic, hepatocellular, or cholestatic/obstructive.
2. Type of circulating bilirubin - conjugated or unconjugated

Question 3

What are the steps of conjugated bilirubin production, starting at red blood cells?

Answer 3

1. RBCs broken down by macrophage into globin and heme.
2. Heme broken down into iron and protoporphyrin which becomes unconjugated bilirubin.
3. Unconjugated bilirubin is transported from the reticular endothelial system to the liver bound to albumin.
4. In the liver hepatocytes, uridine glucuronyl transferase convert unconjugated bilirubin to conjugated bilirubin (glucuronic acid).

Question 4

How is conjugated bilirubin broken down in the small intestine?

Answer 4

1. Conjugated bilirubin is broken down by microbes into urobilinogen.
2. This then breaks down into stercobilin which is excreted, or absorbed into the blood becoming urobilin.
3. Urobilin transported to the liver and kidneys for excretion.

Question 5

What is the pathway of the enterohepatic circulation?

Answer 5

Liver, bile, small intestine, enterocyte, hepatic portal vein, liver.

Question 6

What causes a raised unconjugated bilirubin?

Answer 6

Overproduction (haemolysis), impaired hepatic uptake, impaired conjugation, physiological neonatal jaundice.

Question 7

What causes a raised conjugated bilirubin?

Answer 7

Hepatocellular dysfunction, cholestasis.

Question 8

What are the prehepatic causes of jaundice?

Answer 8

Haemolytic disorders - G6PD, thalassemia, sickle cell anaemia, autoimmune haemolytic anaemia

Question 9

What are the hepatocellular causes of jaundice?

Answer 9

1. Gilbert’s syndrome - benign, mild jaundice during fasting or illness.
2. Acute liver injury - toxic, infective, autoimmune, metabolic and vascular liver insults.
3. Cirrhosis - chronic liver injury from any cause.
4. Hepatic tumours - metastatic

Question 10

What are the results in the LFTs in a hepatocellular cause of jaundice?

Answer 10

Disproportionate rise in ALT and AST relative to ALP and GGT.

Question 11

What are the post hepatic causes of jaundice?

Answer 11

1. Gallstones - most common, relatively rapid onset.
2. Benign strictures - trauma from surgery or consequence of inflammation.
3. Autoimmune - primary biliary cirrhosis or primary sclerosing cholangitis.
4. Malignancy - painless jaundice

Question 12

What are the results in the LFTs in a post hepatic cause of jaundice?

Answer 12

Pronounced rise in ALP and GGT.

Question 13

What is the effect of a post hepatic cause of jaundice on the clotting screen?

Answer 13

Raised PT time due to vitamin K malabsorption from the gastrointestinal tract.

Question 14

Which drug causes prehepatic jaundice?

Answer 14

Anti malarial (Dapsone)

Question 15

Which drugs cause hepatic jaundice?

Answer 15

Paracetamol overdose, cocaine, ecstasy, aspirin/NSAIDs, anti TB medication, antifungal (ketoconazole), antihypertensives (methyl-dopa).

Question 16

Which drugs cause post hepatic jaundice?

Answer 16

Penicillin, macrolides, azathioprine, oestrogens, amitriptyline, carbamazepine, ACEi, cimetidine, ranitidine.

Question 17

What are the risk factors for developing jaundice?

Answer 17

Alcohol, IVDU, sexual activity, piercings, tattoos, hepatitis B/C, blood transfusions, travel abroad, family history, medications.

Question 18

What are the symptoms of jaundice?

Answer 18

Yellow skin/sclera, fatigue, malaise, pruritus, weight loss, anorexia, pale stool, dark urine, may have severe RUQ pain preceding.

Question 19

What are the features of pre-hepatic jaundice on examination?

Answer 19

Mild jaundice, anaemia, splenomegaly, haematuria.

Question 20

What are the features of hepatic jaundice on examination?

Answer 20

Signs of liver failure: spider naevi, clubbing, palmar erythema, gynaecomastia, ascites, asterixis, hepatic encephalopathy, CAGE score >2.

Question 21

What are the features of post-hepatic jaundice on examination?

Answer 21

Hepatomegaly, palpable gallbladder, masses, scars.

Question 22

What are the causes of jaundice in a previously stable patient with cirrhosis?

Answer 22

Sepsis (UTI, pneumonia, peritonitis), malignancy, alcohol, drugs, GI bleed.

Question 23

What are the results of unconjugated serum bilirubin (indirect) in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 23

Pre-hepatic - increase
Hepatic - increased
Post-hepatic - slightly increased

Question 24

What are the results of conjugated serum bilirubin (direct) in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 24

Pre-hepatic - normal
Hepatic - increased
Post-hepatic - moderately increased

Question 25

What are the results of ALT in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 25

Pre-hepatic - normal
Hepatic - markedly increased
Post-hepatic - increased

Question 26

What are the results of ALP in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 26

Pre-hepatic - normal
Hepatic - increased
Post-hepatic - markedly increased

Question 27

What are the results of GGT in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 27

Pre-hepatic - normal
Hepatic - increased
Post-hepatic - markedly increased

Question 28

What are the results of INR in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 28

Pre-hepatic - normal
Hepatic - increased
Post-hepatic - increased

Question 29

What are the results of urine bilirubin in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 29

Pre-hepatic - 0 (normal)
Hepatic - present
Post-hepatic - present (via blood leak)

Question 30

What are the results of urine urobilinogen in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 30

Pre-hepatic - increased
Hepatic - increased
Post-hepatic - 0 (duct blocked)

Question 31

What are the results of urine in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 31

Pre-hepatic - normal
Hepatic - dark
Post-hepatic - dark

Question 32

What are the results of faeces in pre-hepatic, hepatic, and post-hepatic jaundice?

Answer 32

Pre-hepatic - normal
Hepatic - pale
Post-hepatic - pale

Question 33

What investigations should be carried out in jaundice?

Answer 33

1. LFTs, GGT, PT, total protein, albumin, urine, FBC, malaria parasites, U&Es
2. USS to see if bile ducts are dilated - gallstones, hepatic metastases, pancreatic mass

Question 34

What is the management for jaundice?

Answer 34

1. Treat the cause
2. Adequate hydration
3. Broad spectrum antibiotics if obstruction
4. Monitor for ascites and encephalopathy