7.4. Gastroenterology - Approach to the Yellow Baby

Question 1

What are the Different Liver Function Tests?

Answer 1

1. Bilirubin - Total / Split Bilirubin
2. Alanine Aminotransferase (ALT) / Aspartate Aminotransferase (AST)
3. Alkaline Phosphatase
4. Gamma Glutamyl Transferase (GGT)
5. Coagulation - Prothrombin Time (PT / INR) / Activated Thromboplastin Time (APTT)
6. Albumin

Question 2

What Liver Function Tests are elevated in Hepatocellular Damage (Hepatitis)?

Answer 2

1. Bilirubin

2. Alanine Aminotransferase (ALT) / Aspartate Aminotransferase (AST)

Question 3

What Liver Function Tests are Elevated in Biliary Disease?

Answer 3

1. Bilirubin
2. Alkaline Phosphatase
3. Gamma Glutamyl Transferase (GGT)

Question 4

What is the Clinical Manifestation of Paediatric Liver Disease?

Answer 4

1. Jaundice
2. Incidental Finding of Abnormal Boot Test
3. Symptoms / Signs of Chronic Liver Disease - Growth Failure

Question 5

What is Jaundice?

Answer 5

1. Yellow Discolouration of Skin and Tissues due to Accumulation of Bilirubin
2. Usually most obvious in the Sclera
3. Usually Visible when Total Bilirubin > 40-50 umol/L

Question 6

What are the Key Stages of Bilirubin Metabolism?

Answer 6

1. Post-Mature Erythrocytes
2. Unconjugated Bilirubin
3. Liver
4. Conjugation - Conjugated Bilirubin
5. Bile
6. Small Intestine - Urobilinogen
7. a) Liver
8. b) Excreted by Kidneys
9. c) Stercobilin (Faecal Pigment)

Question 7

What are the 3 Types of Neonatal Jaundice?

Answer 7

1. Early - < 24 Hours Old
2. Intermediate - 24 Hours - 2 Weeks Old
3. Prolonged - > 2 Weeks Old

Question 8

What are the causes of Early (< 24 Hours Old) Neonatal Jaundice?

Answer 8

1. Haemolysis
2. Sepsis
   Note - ALWAYS PATHOLOGICAL

Question 9

What are the Causes of Intermediate (24 Hours - 2 Weeks Old) Neonatal Jaundice?

Answer 9

1. Physiological
2. Breast Milk
3. Sepsis
4. Haemolysis

Question 10

What are the Causes of Prolonged (> 2 Weeks Old) Neonatal Jaundice?

Answer 10

1. Extrahepatic Obstruction - Conjugated
2. Neonatal Hepatitis - Conjugated
3. Hypothyroidism - Unconjugated
4. Breast Milk - Unconjugated
   Note - Conjugated Jaundice in infants is ALWAYS abnormal and ALWAYS requires further investigation

Question 11

What is Physiological Jaundice?

Answer 11

Unconjugated Jaundice, Develops after the First Days of Life, due to:

1. Shorter Erythrocyte Life Span in Infants (80-90 days)
2. Relative Polycythaemia
3. Relative Immaturity of Liver Function

Question 12

What is Breast-Milk Jaundice?

Answer 12

Unconjugated Jaundice which can persist up to 12 Weeks.
The Exact Reason for Prolongation of Jaundice in Breastfed Infants in unclear but it is suspected:
1. Inhibition of UDP by Progesterone Metabolite
2. Increased Enterohepatic Circulation

Question 13

What are the Causes of Haemolysis in Early / Intermediate Unconjugated Infant Jaundice?
What are the Tests for these causes?

Answer 13

1. ABO Incompatibility - Blood Group DCT
2. Rhesus Disease - Blood Group DCT
3. Bruising / Cephalhaematoma - Clinical Examination
4. Red Cell Membrane Defects (e.g. Spherocytosis) - Blood Film
5. Red Cell Enzyme Defects (e.g. G6PD) - G6PD Assay

Question 14

What is the Investigation for Sepsis?

Answer 14

1. Urine + Blood Cultures

2. ToRCH Screen - Toxoplasmosis / Rubella / CMV / Herpes

Question 15

What is the Pathology of Kernicterus?

Answer 15

1. Unconjugated Bilirubin is Fat-Soluble so can cross the Blood-Brain Barrier
2. Neurotoxic and Deposits in the Brain

Question 16

What are the Early Signs of Kernicterus?

Answer 16

Encephalopathy

1. Poor Feeding
2. Lethargy
3. Seizures

Question 17

What are the Late Consequences of Kernicterus?

Answer 17

1. Severe Choreoathetoid Cerebral Palsy
2. Learning Difficulties
3. Sensorineural Deafness

Question 18

What is the Treatment of Unconjugated Jaundice?

Answer 18

Phototherapy - Visible Light converts Bilirubin to Water Soluble Isomer (Photoisomerisation)

Question 19

What is the most Important Test in Prolonged Jaundice?

Answer 19

Split Bilirubin

Note - Conjugated Jaundice in infants is ALWAYS abnormal and ALWAYS requires further investigation

Question 20

What are the potential causes of Biliary Obstruction?

Answer 20

1. Biliary Atresia - Conjugated Jaundice / Pale Stools
2. Choledochal Cyst - Conjugated Jaundice / Pale Stools
3. Alagille Syndrome - Intrahepatic Cholestasis / Dysmorphism / Congenital Cardiac Disease

Question 21

What is Biliary Atresia?

Answer 21

Congenital Fibro-Inflammatory Disease of the Bile Ducts leading to Destruction of the Extra-Hepatic Bile Ducts

Question 22

What are the Clinical Features of Biliary Atresia?

Answer 22

1. Prolonged, Conjugated Jaundice
2. Pale Stools
3. Dark Urine
4. May progress to Liver Failure (if not Identified / Treated) - Timely Diagnosis Critical as Determines Prognosis
   Note - Most common indication for Liver Transplantation in Children

Question 23

What must Always be Assessed in Infants with Prolonged Jaundice?

Answer 23

ALWAYS Assess Stool Colour in Infants with Prolonged Jaundice

Question 24

What is the Treatment of Biliary Atresia?

Answer 24

Hepatico-Jejunostomy

Question 25

What is the Aim of Assessment of Prolonged Infant Jaundice?

Answer 25

To Diagnose Patients with Biliary Atresia Early

Question 26

What are the Tests for Biliary Atresia?

Answer 26

1. Split Bilirubin
2. Stool Colour
3. Ultrasound
4. Liver Biopsy

Question 27

What are the Tests for a Choledochal Cyst?

Answer 27

1. Split Bilirubin
2. Stool Colour
3. Ultrasound

Question 28

What are the Tests for Alagaille Syndrome?

Answer 28

1. Dysmorphism

2. Genotype

Question 29

What are the Causes of Neonatal Hepatitis?

What are the Tests for these Causes?

Answer 29

1. Alpha-1-Antitrypsin Deficiency - Phenotype / Level
2. Galactosaemia - GAL-1-PUT
3. Tyrosinaemia - Amino-Acid Profile
4. Urea-Cycle Defects - Ammonia
5. Haemochromatosis - Iron Studies / Liver Biopsy
6. Glycogen Storage Disorders - Biopsy
7. Hypothyroidism - Thyroid Function Tests
8. Viral Hepatitis - Serology / PCR
9. Parenternal Nutrition - History