Approach to the Jaundiced Baby Flashcards

1
Q

Liver functions

A

Production of proteins essential for day-to-day life, particularly albumin, and clotting factors
Metabolism - absorption, digestion and processing of fat, carbohydrate and protein
Role in storage of fat, carbohydrate and protein, particularly glycogen
Filter of toxic metabolites (and drugs) - processed and excreted

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2
Q

Liver function tests

A

Bilirubin

  • Total bilirubin
  • Split bilirubin; direct (conjugated) and indirect (unconjugated)

ALT/AST
(alanine aminotransferase/aspartate aminotransferase)
- elevated in hepatocellular damage

Alkaline phosphatase
- elevated in biliary disease, useful in adults but not as helpful in paediatrics

Gamma glutamyl transferase (GGT)
- elevated in biliary disease

These are markers of liver damage rather than liver function

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3
Q

Tests to assess liver function (rather than liver damage)

A
Coagulation - prothrombin time (PT)/INR, APTT
Albumin 
Bilirubin 
Blood glucose 
Ammonia
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4
Q

Clinical manifestations of paediatric liver disease

A

Jaundice (!!!)
Incidental finding of abnormal blood test
Symptoms/signs of chronic liver disease are rarely seen

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5
Q

Signs of liver disease in children

A

Same manifestations as in adults plus growth failure

  • jaundice
  • cholestasis
  • spider naevi
  • muscle wasting
  • splenomegaly
  • ascites
  • epistaxis

etc.

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6
Q

What is jaundice and when is it most obvious?

A

Jaundice is the yellow discolouration of skin and tissues due to accumulation of bilirubin
Usually most obvious in sclera, usually visible when total bilirubin > 40-50umol/l

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7
Q

Describe bilirubin metabolism

A

Starts in erythrocytes
Erythrocytes broken down to haem, breakdown product is biliverdin
Biliverdin is acted on by biliverdin reductase in all tissues to form unconjugated bilirubin
Unconjugated bilirubin is albumin-bound and transported to the liver
In the liver, conjugation occurs by UDP glucuronyl transferase
Conjugated bilirubin present in bile which is transported to small intestine
In small intestine, bilirubin is converted to urobilinogen which is either transported back to the liver and recycled, excreted by the kidneys or converted to stercobilin which is excreted in stool

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8
Q

What kind if bilirubin is most commonly present in pre-hepatic, intra-hepatic and post-hepatic jaundice?

A

Pre-hepatic most commonly unconjugated bilirubin

Intra-hepatic most commonly mixed i.e. unconjugated and conjugated bilirubin

Post-hepatic most commonly conjugated bilirubin

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9
Q

What is the classification of neonatal jaundice?

A

Classification by age

Early

  • < 24 hours old
  • always pathological
  • e.g. due to haemolysis or sepsis

Intermediated

  • 24 hours to 2 weeks old
  • can be a normal physiological process due to breast milk
  • may be sepsis or haemolysis

Prolonged

  • > 2 weeks old
  • caused by extra-hepatic obstruction, neonatal hepatitis, hypothyroidism or breast milk
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10
Q

Features of physiological jaundice

A
Shorter RBC lifespan in infants (80-90 days) 
Relative polycythaemia 
Relative immaturity of liver function 
Unconjugated jaundice 
Develops after first day of life
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11
Q

Features of breast milk jaundice

A

Exact reason for prolongation of jaundice in breastfed infants is unclear
Unconjugated jaundice
Can persist up to 12 weeks

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12
Q

Causes of early/intermediate unconjugated infant jaundice

A

Sepsis

Haemolysis

  • ABO incompatibility
  • Rhesus disease
  • bruising/cephalhaematoma
  • red cell membrane defects e.g. spherocytosis
  • red cell enzyme defects e.g. G6DP

Abnormal conjugation

  • Gilbert’s disease (common, mild)
  • Crigler-Najjar syndrome (very rare, severe)
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13
Q

Investigations for jaundice when suspecting sepsis, haemolysis or abnormal conjugation

A

Sepsis - urine and blood cultures, TORCH screen

Haemolysis

  • blood group
  • DCT (ABO incompatibility and Rhesus)
  • clinical examination (bruising)
  • blood film (RBC membrane defects)
  • G6DP (RBC enzyme defects)

Abnormal conjugation - genotype/phenotype

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14
Q

Features of Kernicterus

A

Complication of neonatal jaundice
Unconjugated bilirubin is fat-soluble (water-insoluble) so can cross blood brain barrier
Neurotoxic, deposits in brain

Early signs - encephalopathy, poor feeding, lethargy, seizures

Later consequences - severe choreoathetoid cerebral palsy, learning difficulties, sensorineural deafness

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15
Q

Use of phototherapy in jaundice treatment

A

Treatment for unconjugated jaundice
Visible light (450nm wavelength, not UV) used
Converts bilirubin to water soluble isomer (photoisomerisation)

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16
Q

What is the threshold for phototherapy in infants guided by?

A

Charts

17
Q

What is prolonged infant jaundice?

A

Jaundice persisting beyond 2 weeks of life, 3 weeks for pre-term infants

18
Q

Causes of prolonged infant jaundice

A

Anatomical e.g. biliary obstruction or neonatal hepatitis - conjugated

Hypothyroidism, breast milk - unconjugated

Conjugated jaundice in infants is always abnormal and always requires further investigation

19
Q

What is the most important test in prolonged infant jaundice?

A

Split bilirubin

20
Q

Causes of biliary obstruction

A

Biliary atresia - conjugated jaundice, pale stools

Choledochal cyst - conjugated jaundice, pale stools

Alagille syndrome - intrahepatic cholestasis, dysmorphism, congenital cardiac disease

21
Q

What should you always assess in infants with prolonged jaundice?

A

Always assess stool colour in infants with prolonged jaundice

22
Q

What is biliary atresia?

A

Congenital fibro-inflammatory disease of bile ducts leading to destruction of extra-hepatic bile ducts

23
Q

Features of biliary atresia

A

Presents with prolonged conjugated jaundice
Pale stools, dark urine
Progression to liver failure if not identified and treated

24
Q

Why is timely diagnosis of biliary atresia critical?

A

Time to treatment determines prognosis

25
Q

What is the most common indication for liver transplantation in children?

A

Biliary atresia

26
Q

Treatment of biliary atresia

A

Kasai portoenterostomy

Liver transplantation

27
Q

Features of Kasia Portoenterostomy for treating biliary atresia

A

Success rate diminishes rapidly with age
Best results if performed before 60 days, after this point most children will go straight to liver transplantation
Small intestine connected to liver

28
Q

Investigations for prolonged infant jaundice caused by biliary obstruction

A

Biliary atresia - split bilirubin, stool colour, ultrasound, liver biopsy

Choledochal cyst - split bilirubin, stool colour, ultrasound

Alagille syndrome - dysmorphin, genotype

29
Q

Causes of prolonged neonatal jaundice and appropriate investigations for these

A

Alpha-1-antitrypsin deficiency - phenotype/level

Galactosaemia - GAL-1-PUT

Tyrosinaemia - amino acid profile

Urea cycle defects - ammonia

Haemochromatosis - iron studies, liver biopsy

Glycogen storage disorders - biopsy

Hypothyroidism - TFTs

Viral hepatitis - serology, PCR

Parenteral nutrition - history