Paediatric Jaundice and Metabolism Flashcards
what are the main functions of the liver?
- toxin excretion
- nutrient storage
- production of clotting factors & plasma proteins
- nutrient metabolism
- bile production
which liver function tests assess liver damage?
- aminotransferases (AST/ALT)
- ALP
- gamma GT
- bilirubin
what does split bilirubin measure?
conjugated (direct) and unconjugated (indirect) bilirubin
why is ALP not often used as a marker for liver damage in children?
because ALP is also found in bone, and growing bone in children will produce higher levels of ALP
what are high levels of aminotransferases indicative of?
cell damage
what is raised gamma GT an indicator of?
biliary tree damage
what is raised ALP an indicator of in liver disease?
biliary tree damage
what are raised aminotransferases an indicator of in liver disease?
hepatocellular damage
which raised aminotransferase is normally specific to liver cell damage?
ALT
which raised aminotransferase can be an indicator of muscle cell damage?
AST
which liver function tests indicate damage to the biliary tree?
ALP
gamma GT
which lab tests assess liver function?
- coagulation factors (PT/INR/APTT)
- albumin
- bilirubin
- blood glucose and ammonia in severe liver disease
how do children with liver disease present?
with jaundice
how can you differentiate between jaundice and beta carotenaemia?
jaundice also affects sclera, beta carotenaemia only affects skin
what is the main difference in presentation of chronic liver disease in children vs adults?
in children liver disease also presents with growth failure
what is the average level of bilirubin above which infants become jaundiced?
> 40-50umol/l
describe bilirubin metabolism
- RBC broken down by reticuloendothelial system (haem + globin)
- haem becomes biliverdin
- biliverdin becomes bilirubin (unconjugated - UC)
- UC bilirubin is transported to liver by albumin
- glucuronic acid in liver conjugates bilirubin
- conjugated bilirubin enters small intestine as urobilinogen
- urobilinogen goes one of there ways : 1. back to liver; 2. excreted by kidneys; 3. excreted in stool as stercobilin
in pre-hepatic jaundice, is bilirubin conjugated or unconjugated?
mostly unconjugated
in intrahepatic jaundice, is bilirubin unconjugated or conjugated?
mixed unconjugated and conjugated
in post-hepatic jaundice, is bilirubin unconjugated or conjugated?
mostly conjugated
why is it important to know the age of a child with jaundice?
because their age can indicate the most likely cause for the jaundice
what are the three classifications of jaundice by age?
early (<24hours old)
intermediate (24 hours - 2 weeks)
prolonged (>weeks)
when does physiological jaundice normally present?
after first day of life
what causes physiological jaundice?
- infants are polycythaemic
- short RBC half life
- liver not fully developed, so bilirubin conjugation takes longer
which type of jaundice is always abnormal in infants?
early jaundice - if less than 24 hours old
name a few causes of early neonatal jaundice
sepsis
haemolysis
what type of jaundice can be seen as a result of breast milk?
prolonged jaundice - unconjugated
name a few causes of prolonged neonatal jaundice
- extrahepatic obstruction
- neonatal hepatitis
- hypothyroidism
- breast milk
what type of jaundice is physiological jaundice in infants?
intermediate jaundice, unconjugated
what are the two conjugation disorders which can cause early/intermediate jaundice in infants?
Gilbert’s syndrome (mild)
Crigler-Najjar syndrome (severe)
despite physiological jaundice not being dangerous, what important complication needs to be avoided?
kernicterus
what is kernicterus?
build up of unconjugated bilirubin in basal ganglia, resulting in encephatlopathy, learning difficulties, sensorineural deafness, choreoathetoid cerebral palsy
why can physiological jaundice cause kernicterus in infants?
because in physiological jaundice bilirubin is unconjugated therefore fat soluble = it can cross the BBB
how is unconjugated infant jaundice treated?
phototherapy - converts unconjugated bilirubin into a water soluble isomer
why can infants present with haemolysis resulting in early jaundice?
- hereditary red cell abnormalities (eg spherocytosis, G6PD)
- blood type incompatibility (ABO, rhesus)
what is the most important cause for prolonged conjugated infant jaundice?
biliary atresia
what is biliary atresia?
congenital auto-immune condition leading to fibrosis/destruction of biliary tree
what is prolonged infant jaundice?
jaundice lasting beyond 2 weeks of life
if an infant presents with unconjugated prolonged jaundice, what are the likely causes?
breast milk
hypothyroidism
what is the most crucial test to do in infants presenting with prolonged jaundice?
split bilirubin
what clinical sign should never be missed in infants presenting with prolonged jaundice?
pale stools - steatorrhea
what is the appearance of stool and urine in biliary atresia?
dark urine
pale stool
what is the surgical treatment of biliary atresia?
Kasai portoenterostomy
when is a Kasai portoenterostomy beneficial in infants with biliary atresia?
if they are under 2 months old
if an infant with biliary atresia is older than 2 months, what is the best management option?
waiting list for liver transplant
what is the main reason for assessing infants with prolonged jaundice?
for early detection and treatment of biliary atresia
what investigations are done to diagnose biliary atresia?
- split bilirubin
- stool sample
- ultrasound
- liver biopsy
which types of infant jaundice are always pathological?
- early infant jaundice
- prolonged conjugated jaundice
name a few causes of neonatal hepatitis
anything that causes liver inflammation: alpha 1 anti trypsin deficiency galactosaemia hypothyroidism haemochromatosis viral hepatitis urea cycle defects glycogen storage disorders
how does alpha 1 anti trypsin deficiency affect children vs adults?
children: liver damage (hepatitis)
adults: lung damage (emphysema)
