Jaundice and Bilirubin Flashcards

1
Q

What is jaundice?

A

Yellow pigmentation of the skin or sclerae, caused by high levels of unconjugated or conjugated bilirubin in the blood

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2
Q

When is jaundice clinically apparent?

A

Plasma bilirubin concentration >50uM/L

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3
Q

Where is bile stored and concentrated?

A

Gallbladder

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4
Q

What causes bile to be released?

A
  • CCK (cholecystokinin)

- Vagal response to food

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5
Q

What is bile composed of?

A
  • Bile pigments (Hb breakdown products)

- Bile salts (derived from cholesterol and help emulsify fat)

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6
Q

What is bilirubin?

A

Hb breakdown product

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7
Q

Give an overview of bilirubin metabolism:

A
  1. Formed as a breakdown product of haemoglobin
  2. Conjugated in the liver to form a water-soluble molecule
  3. Extricated in the bile
  4. Metabolised in the gut by bacteria into urobilinogen and stercobilin
  5. Urobilinogen is reabsorbed and excreted in the liver
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8
Q

What is pre-hepatic jaundice?

A

Unconjugated hyperbilirubinemia

- Excess production of bilirubin that overtakes the ability of liver to conjugate the bilirubin and excrete into the gut

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9
Q

What can cause pre-hepatic jaundice?

A
o	Haemolytic anaemia 
o	RBC abnormality (sickle cell)
o	Incompatible blood transfusion
o	Drug reaction
o	Hypersplenism
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10
Q

What are the symptoms of pre-hepatic jaundice?

A
  • Skin yellowing
  • Pale urine
    unconugated bilirubin is water-insoluble so does not enter urine
  • Dark stools (normal)
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11
Q

What is the reason for the symptoms in pre-hepatic jaundice?

A
  • Liver function in patients with haemolytic jaundice is normal, but because of increased RBC breakdown, glucuronyl transferase is saturated.
  • The liver compensates by increasing conjugated bilirubin output, making the stools dark (normal).
  • This unconjugated bilirubin cannot be excreted in urine as it is not water soluble, so there is little/no bilirubin the urine causing pale urine
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12
Q

What is hepatic jaundice?

A

Conjugated and unconjugated hyperbilirubinemia
- Due to parenchymal liver disease (Intrinsic abnormality of the hepatocyte) with inability to either conjugate, uptake or excrete bilirubin.

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13
Q

What can cause hepatic jaundice?

A
  • Congenital
  • Acquired
    Infection (viral hepatitis)
    Cirrhosis (alcohol)
    Cirrhosis (NASH)
    Damage by toxins or drugs
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14
Q

What are the symptoms of hepatic jaundice?

A
  • Skin yellowing
  • Variable Dark urine
  • Variable Pale stools
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15
Q

In hepatocellular damage what would the LFTs show?

A

INCREASED:

  • ALT (markedly)
  • AST
  • GGT
  • Bilirubin
  • Alk. phos (mildly)
  • INR

Rise in ALT, AST&raquo_space; rise in alk phos

DECREASED:
- Albumin

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16
Q

What would you find on examination with hepatic jaundice?

A
  • Dull RUQ pain

- US: liver enlarged/shrunken with or without splenomegaly

17
Q

What is post-hepatic jaundice?

A

An impediment to the flow of bile due to a partial or complete obstruction of the extrahepatic biliary passage between the liver and duodenum.

18
Q

What can cause post-hepatitc jaundice?

A
•	Obstruction of bile duct by stone
•	Obstruction of bile duct by tumour
      Head of pancreas
      Cholangiocarcinoma
      Lymph Node metastasis
•	Also consider intra-hepatic cholestasis
      Primary biliary cholangitis
      Primary sclerosing cholangitis
19
Q

What is cholestasis?

A

A decrease in bile flow due to impaired secretion by hepatocytes or to obstruction of bile flow through intra-or extrahepatic bile ducts.

20
Q

What are the symptoms with post-hepatic jaundice?

A
  • Skin yellowing
  • Dark urine
    Liver fucntion is normal, so bile is conjugated
  • Pale stools
    No bilirubin in intestine
21
Q

In post-hepatic jaundice what would the LFTs show?

A
INCREASED:
- ALT (mildly)
- AST
- ALP (markedly)
- INR (maybe)
      can be correctable with Vitamin K
- Bilirubin

Rise in ALT, AST &laquo_space;rise in alk phos

UNCHANGED:
- Albumin

22
Q

What would you find on examination with post-hepatic jaundice?

A
  • Colicky RUQ pain
    Pain that stops and starts abruptly
  • US/CT: cholelithiasis, dilated biliary tree, SOL (space occupying lesions), gallbladder stones
  • Pruritis
23
Q

When is neonatal jaundice detectable?

A

Serum bilirubin > 85 micromoles/litre

24
Q

Which type of jaundice is more common in newborns?

A

Unconjugated hyperbilirubinaemia

25
Q

Which type of jaundice is toxic in newborns and why?

A

Unconjugated hyperbilirubinaemia

  • Can penetrate the blood-brain barrier
  • Stains neurological tissue, causing kernicterus (brain damage)
  • Causes bilirubin encephalopathy
26
Q

How do you prevent neonatal jaundice from worsening?

A
  • Fluid and caloric intake
27
Q

How do you treat neonatal unconjugated hyperbilirubinaemia?

A
  • Phototherapy
    Light treatment breaks down bilirubin molecules
  • Exchange transfusion
28
Q

How do you treat neonatal conjugated hyperbilirubinaemia?

A
  • Manage the obstruction
29
Q

What would you look for in the history of an adult with jaundice?

A
•	Drug and alcohol Hx
•	Cigarette use
•	Foreign travel
•	Sexual Hx
      Association with Heb B and obstructive jaundice
•	Colour of urine and stools
•	Duration
•	Jaundice with or without pain
      Painless = classic symptom of pancreatic cancer
30
Q

What investigations would you order for jaundice?

A
- FBC
      Infection?
- Urea and electrolytes
      Renal impairment 
- LFTs
- Clotting screen
- Amylase
      If pancreatitis is suspected
- Hep A, B and C
      If risk factors present
- Urine dipstick
      Indicates increased conjugated bilirubin
31
Q

If obstructive jaundice is NOT suspected, what tests would you order?

A
  • Viral hepatitis screen
    hepatitis A, B, and C.
  • Immunoglobulins.
  • Auto-antibody profile
    High levels of IgM are characteristic of primary Biliary cholangitis
    High levels of IgG indicate chronic active hepatitis.
    ANA/SMA/LKM1 antibodies, raised IgG levels in autoimmune hepatitis
  • Ferritin (and transferrin saturation if ferritin is raised)
    Screen for hereditary haemochromatosis.
  • Alpha1-antitrypsin.
  • Alpha-fetoprotein
    Increased levels may indicate hepatocellular carcinoma.
  • Caeruloplasmin.
  • Thyroid function tests
32
Q

What would you identify in a focused history for jaundice?

A
•	Drug and alcohol Hx
•	Cigarette use
•	Foreign travel
•	Sexual Hx
      Association with Heb B and obstructive jaundice
•	Colour of urine and stools
•	Duration
•	Jaundice with or without pain
      Painless = classic symptom of pancreatic cancer
33
Q

What might you see in an examination for jaundice?

A

• Sclera and skin
• Scratches from puritis/itching (bilirubin breakdown can cause itching)
• Evidence of weight loss (thenar wasting)
Indication that underlying jaundice is due to malignancy
Troisier’s node (left supraclavicular node enlargement)
o Indication that underlying jaundice is due to malignancy

34
Q

What are the red flags for jaundice?

A
•	Hepatic encephalopathy:
      Confusion or alteration in mental state
      Altered neuromuscular function
        - Poor coordination
        - Ataxia
        - Asterixis
        - Nystagmus
•	Hepatic dysfunction
      Bruising, purpura or petechiae
•	GI blood loss
      Haematemesis or melaena
•	Sepsis
      Fever, hypotension and tachycardia
•	Marked abdominal tenderness or pain
•	Vomiting
•	Suspected paracetamol overdose
35
Q

What does bile leave the liver through?

A

Common hepatic duct

36
Q

How does bile get into the gallbladder?

A

Cystic duct

37
Q

When bile is released from the gallbladder, what does it travel through?

A

Common bile duct