Neonatal Jaundice Flashcards
What is neonatal jaundice?
A yellowish discolouration of the white part of the eyes and skin in a newborn baby due to high bilirubin levels
What produces unconjugated bilirubin?
The breakdown of RBC - it is produced from haem
How does unconjugated bilirubin circulate?
Bound to albumin
What type of bilirubin is capable of crossing the blood brain barrier?
Bilirubin free in the plasma - it can cross the blood brain barrier if it is in high quantities
What is the pattern of progression of jaundice in a newborn?
Cephalo-caudal
Face to toes
What is the process of bilirubin metabolism?
Unconjugated bilirubin is metabolised by the liver to conjugated bilirubin which is excreted by the gut
Which type of bilirubin is water soluble?
Conjugated bilirubin
What enzymes are involved in liver metabolism of bilirubin?
Ligandin - moderates bilirubin uptake
Uridine Diphosphoglycuronyltransferase - modulates bilirubin conjugation
Why are newbons inefficient at managing bilirubin?
The enzymes ligandin and UDPGT are physiologically low in a newborn
Why is some of the conjugated bilirubin converted back to unconjugated bilirubin in a newborn?
Due to the alkaline environment and enzymes in the intestines
Name an enzyme abnormality that can affect bilirubin conjugation…
Gilberts Disease - mutation of the UGT1A1 gene
What is kernicterus?
Cerebral palsy related to bilirubin encephalopathy
What are risk factors for neonatal jaundice?
Decreasing gestation - more preterm = higher risk Asphyxia Acidosis Hypoxia Hypothermia Meningitis Sepsis
What are causes of neonatal juandice?
Physiological Haemolysis Sepsis Metabolic Disorders Liver Disease Physiological Jaundice that is too high --> can cross BBB
What is the timing of physiological jaundice?
24-72 hours
