epickrot.blogg.se - Pathological jaundice newborn

Unconjugated jaundice can be caused by neonatal sepsis, haemolysis, or endocrine/metabolic disorders. While most cases of neonatal jaundice do not have a pathological cause, many underlying diseases can present with jaundice. The breakdown of RBCs within the cephalohaematoma causes higher bilirubin levels and predisposes to jaundice.

Babies with significant bruising or cephalohaematoma: which can occur in difficult deliveries.

Prolonged jaundice in breastfed babies is sometimes referred to as ‘breast milk’ jaundice.

Breastfed babies: experience more marked and prolonged jaundice than formula-fed infants for reasons that are not completely understood.

Preterm babies: tend to have higher bilirubin levels and more prolonged jaundice than term infants.

Some neonates are more prone to jaundice: 2

A relatively high concentration of β-glucuronidase in the small intestine.

Shorter lifespan of neonatal red blood cells.

Mechanisms behind physiological jaundice include: 3 1 Physiological jaundice is unconjugated and usually presents on the second or third day of life. Jaundice is often a normal phenomenon in neonates, with no underlying pathology. Stercobilinogen is oxidised to stercobilin, which gives faeces its brown colour. Urobilinogen is oxidised to urobilin, which gives urine its yellow colour. The remaining conjugated bilirubin is metabolised by intestinal bacteria to produce urobilinogen and stercobilinogen. This unconjugated bilirubin re-enters the circulating pool of bilirubin via the enterohepatic circulation.

Conjugated bilirubin is water-soluble but lipid insoluble, so it cannot cross the blood-brain barrier.Ĭonjugated bilirubin is transported to the small intestines via the biliary system and some is converted back to unconjugated bilirubin by the enzyme β-glucuronidase. Most unconjugated bilirubin circulates bound to albumin, but some circulate as ‘free’ bilirubin, which is lipid-soluble and can cross the blood-brain barrier.Īn enzyme in the liver, called UDP-glucuronosyltransferase (UGT), converts unconjugated bilirubin to conjugated bilirubin by adding an amino acid.

3īilirubin is produced from the breakdown of red blood cells (RBCs). Understanding neonatal jaundice requires knowledge of bilirubin metabolism (Figure 1). You might also be interested in our medical flashcard collection which contains over 1000 flashcards that cover key medical topics.Īetiology Physiology of bilirubin metabolism