Obstructive Jaundice

Question 1

Classify the different causes of cholestatic jaundice?

Answer 1

Intrahepatic cholestasis:
Inflammatory changes in the ductal cells cause there to be no bile secretion.

Extrahepatic cholestasis:
Large duct obstruction of bile flow at any point in the biliary tract distal to the bile canaliculi (tube which collects bile from the hepatocytes)

Question 2

Describe and explain the classical clinical features of obstructive jaundice?

Answer 2

Jaundice: due to build up of bilirubin

Pale stools: because obstruction no excretion of sterobilin (gives faeces a brown colour).

Dark Urine: Urine urobilinogen levels are low. Large quantities of conjugated bilirubin excreted by the kidneys giving the urine a very dark colour.

Pruritis: accumulated bile salts

Poor fat absorption: steatorrhea as bile is not available to emulsify fats

Question 3

What laboratory and radiological investigations could be done to help make a diagnosis in a jaundiced patient?

Answer 3

Urine:
Bilirubin absent in non-obstructive causes.
Urobilinogen low in obstructive causes.

Bloods:
FBC: Low Hb in haemolytic causes
Raised WBC will indicate an infectious cause, (cholangitis)
Leukopenia suggests viral infection.

LFTs:
Bilirubin conjugated/nonconjugated.
Hepatocellular damage:
Alcoholic AST:ALT 2:1
V. high ALP suggests obstructive.
Low albumin suggests chronic.

Viral Serology

Scans:
Ultrasound to look for biliary stones/obstruction
Abdominal CT if malignancy suspected (painless jaundice)

Question 4

Describe the symptoms and pathophysiology of cholelithiasis (gallstones)?

Answer 4

Gallstones are stones formed from bile when there is to high a ratio of cholesterol to bile salts.

They are more common in the 4F’s:
Fat, Fertile (oestrogen) , Forty yo, Females,

Patients with gallstones may be asymptomatic ‘silent stones’ or may suffer from gallstone attacks.

Gallstone attacks present with severe sudden onset epigastric or right upper quadrant pain. It is often associated with nausea and vomiting.

Gallstone attacks are more frequent at night and are often precipitated by a fatty meal or alcohol.

Consequences: If a gallstone blocks drainage of bile from the gallbladder it will cause cholecystitis (infection of the gallbladder)

If a gallstone blocks another part of the biliary tree it can case cholangitis (infection of the bile duct, medical emergency)

If it blocks drainage from the pancreas (pancreatic duct) it can cause pancreatitis.

Question 5

Describe the presentation and pathological consequence of pancreatic carcinoma?

Answer 5

Presents with painless obstructive jaundice, (usually severe jaundice), weight loss.

May become painful as the tumour progresses.

Courvoisier’s sign positive: palpable gallbladder which is non tender the pathology is unlikely to be with the gall bladder.

May be lympathendopathy and splenomegaly.

Very poor prognosis 5 year mortality very low even with treatment.

Question 6

Describe the difference between unconjugated and conjugated bilirubin?

Answer 6

• *Unconjugated bilirubin:**
• *Bound** to albumin (cannot be excreted in urine) and circulates to the liver where conjugated to glucuronic acid

Conjugated bilirubin:
Excreted in the bile to reach the gut.
n the distal gut, bacteria split the conjugate into urobilinogen, most of which exits in the faeces. However, 20% is resorbed into the blood and re-excreted by the liver (enterohepatic recirculation)

A very small amount of resorbed urobilinogen is excreted in the urine. Unconjugated bilirubin is lipid soluble. Dangerous if present at high conc as it saturates albumin -> (kernicterus)

Question 7

DDx of Intrahepatic and extrahepatic obstructive jaundice

Answer 7

Most come cause is obstruction of bile secretion

Intrahepatic obstructive jaundice:

• Primary biliary cirrhosis
• Primary sclerosing cholangitis
• Alcohol
• Drugs
• Viral hepatitis

Extrahepatic obstructive Jaundice:

• Choledocholithiasis (CBD gallstone)
• Carcinoma:
  
  • Ampullary
  • Pancreatic
  • Bile Duct (cholangiocarcinoma)
  • Secondary

Question 8

Discuss Imaging methods for an obstructed common bile duct

Answer 8

1st line USS: high proximity of USS probe allows less invasive bile duct imaging

MRCP allows detailed imaging of the biliary tree without administration of contrast

ERCP involves passage endoscope into the second part of the duodenum and cannulation of the ampulla.
Contrast is injected into both systems

Can remove common bile duct stones with therapeutic ERCP
NB pancreatitis is common complication