Jaundice Flashcards

1
Q

what are the three classifications of jaundice?

A
  • pre-hepatic
  • intrahepatic
  • post-/extra-hepatic
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2
Q

what is pre-hepatic jaundice?

A
  • occurs when bilirubin metabolism is affected before it reaches the liver, resulting in unconjugated hyperbilirubinemia
  • it is typically caused by increased red cell haemolysis, which produces excess unconjugated bilirubin
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3
Q

how does haemolytic anaemia contribute to increased bilirubin levels?

A
  • increases bilirubin due to increased haemolysis of red blood cells
  • haemolysis can occur intravascularly or extravascularly (where phagocytes remove defective or antibody-coated red cells)
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4
Q

what are the genetic causes of haemolytic anaemia?

A
  • red cell membrane defects (e.g. hereditary spherocytosis)
  • haemoglobin abnormalities (e.g. sickle cell anaemia, thalassaemia)
  • enzyme deficiencies (e.g. G6PD deficiency, pyruvate kinase deficiency)
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5
Q

what are the causes of acquired haemolytic anaemias?

A

acquired haemolytic anaemias are often immune-mediated and can be:

  • isoimmune (e.g. blood transfusion reaction)
  • autoimmune (e.g. SLE, lymphoma, leukaemia, drug-related)
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6
Q

what are non-immune causes of acquired haemolytic anaemia?

A
  • disseminated intravascular coagulation (DIC)
  • haemolytic uraemic syndrome (HUS)
  • thrombotic thrombocytopenia
  • hypersplenism
  • cirrhosis
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7
Q

what is gilbert’s syndrome?

A

a benign genetic condition where bilirubin is not transported into bile at the usual rate, causing intermittent jaundice due to unconjugated hyperbilirubinaemia

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8
Q

what is crigler-najjar syndrome?

A
  • a rare autosomal recessive disorder where deficiency of diphosphate glucuronosyltransferase impairs bilirubin conjugation and excretion, leading to unconjugated hyperbilirubinaemia
  • it typically presents in neonates
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9
Q

what is intrahepatic jaundice?

A

occurs when hepatocyte damage reduces bilirubin conjugation or causes cholestasis

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10
Q

what are the three clinical phases of viral hepatitis?

A
  1. prodromal
  2. icteric
  3. convalescent
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11
Q

what is alcoholic hepatitis?

A
  • occurs when the liver metabolises alcohol, producing acetaldehyde as a by-product
  • this binds to proteins in liver cells, causing hepatocyte injury
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12
Q

what is decompensated cirrhosis?

A
  • irreversible scarring of the liver with abnormal nodules
  • symptoms of liver failure only become apparent when 80-90% of hepatic tissue is damaged
  • it causes portal hypertension due to distortion of intrahepatic vasculature by fibrosis
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13
Q

what can trigger decompensation in a patient with cirrhosis?

A
  • infection (e.g. SBP)
  • bleeding (e.g. variceal bleeding)
  • alcohol binge
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14
Q

what is primary biliary cholangitis (PBC)?

A
  • a slowly progressive autoimmune disease that destroys small interlobular bile ducts, causing intrahepatic cholestasis
  • this leads to hepatocyte damage, and fibrosis + can eventually progress to cirrhosis
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15
Q

what causes extra-hepatic jaundice?

A

occurs due to extra-hepatic cholestasis, often caused by:

  • intraluminal structural abnormalities (e.g. strictures)
  • extrinsic compression (e.g. tumours or gallstones)
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16
Q

how can malignancies cause bile duct obstruction?

A
  • intraluminal obstruction (e.g. inside the common bile duct or gallbladder)
  • extrinsic compression (e.g. pancreatic cancer)
17
Q

what are the key features of cholangiocarcinoma in relation to jaundice?

A
  • cancer of the gallbladder or bile duct that causes intraluminal obstruction of bile flow
  • it often presents late with jaundice, RUQ pain + weight loss
18
Q

What are the key features of pancreatic cancer in relation to jaundice?

A
  • cancer of the head of the pancreas can cause extrinsic compression of the biliary tree, blocking bile flow
  • it typically presents late with jaundice, weight loss + abdominal pain
19
Q

how can pancreatitis cause jaundice?

A
  • pancreatitis is inflammation of the pancreas, which presents with severe epigastric pain + vomiting
  • jaundice can occur due to a common bile duct stone, excess alcohol use, or extrinsic compression of the common bile duct from pancreatic inflammation and swelling
20
Q

what blood tests are used to investigate suspected pre-hepatic jaundice or haemolytic anaemia?

A
  • haptoglobin (e.g. binds free Hb): ↓ in haemolytic anaemia
  • lactate dehydrogenase (LDH): ↑ due to increased haemolysis
  • blood film: identifies red cell abnormalities or haematological malignancy
  • split bilirubin test: measures conjugated/unconjugated bilirubin — ↑ unconjugated bilirubin indicates pre-hepatic jaundice
21
Q

what do LFTs show in hepatocellular jaundice?

A
  • ↑ AST & ALT
  • AST:ALT > 2:1 - ArLD
  • ↑ GGT - EtOH
22
Q

how is ascitic fluid analysed?

A

ascitic fluid is collected by ascitic aspiration + sent for:

  • M, C & S
  • gram staining is used to identify any organisms initially + count numbers of white cells
23
Q

what does a raised white cell count in ascitic fluid indicate?

A

> 250/µL ( ↑ polymorphic) - SBP
250/µL ( ↑ lymphocytic) - TB

24
Q

how is alcohol cessation supported in patients with liver disease?

A
  • benzodiazepines (e.g. lorazepam, chlordiazepoxide)
  • vitamin replacement with intravenous thiamine/B12 (Pabrinex)
25
when is ursodeoxycholic acid used?
it helps prevent the formation of gallstones by reducing bile acid production
26
how is pruritis caused by jaundice managed?
colestyramine is a bile acid sequestrant that prevents the reabsorption of bile acids, helping reduce itching in obstruction of the biliary tree (e.g. PBC)