Physiological Jaundice Flashcards Preview

MIDW1002 Scientific Underpinnings of Midwifery Care > Physiological Jaundice > Flashcards

Flashcards in Physiological Jaundice Deck (4)
Loading flashcards...
1
Q

Describe what bilirubin is and how it is broken down and excreted

A
  • bilirubin is a breakdown product of haemoglobin from red blood cells
  • ageing, immature or malformed red blood cells are removed from the circulation and broken down in the reticuloendothelial system (liver, spleen and macrophages)
  • haemoglobin in the red blood cells are broken down into byproducts of haem, globin and iron
    - -> haem is converted to bilverdin and then unconjugated bilirubin
    - -> globin is broken down into amino acids which are used in the body to make new proteins
    - -> iron is stored in the body or used for new red blood cells
  • the unconjugated bilirubin is then transported to the liver bound to serum albumin
    - -> once in the liver unconjugated bilirubin is detached from albumin, combined with glucose and glucuronic acid
    - -> this causes conjugation to occur using the enzyme uridine diphosphoglucuronyl transferase (UDP-GT)
  • the conjugated bilirubin is now water-soluble and available for excretion
  • it is excreted via the biliary system into the small intestine where normal bacteria change the conjugated bilirubin into urobilinogen
  • this is then oxidised into orange-coloured urobilin
  • most is excreted in the faeces with a small amount in urine
2
Q

What causes physiological jaundice?

A
  • all newborn babies have a rise in unconjugated bilirubin during the first few days after birth which occurs for several reasons
    - -> the turnover of haemoglobin is high in the fetus and newborn but before birth the bilirubin from the fetus is removed via the placenta
    - -> at birth as the more efficient lungs increase oxygen levels, there is haemolysis of excessive RBC’s that are now not needed
    - -> at birth the newborn liver enzyme systems may be immature and not as effective
  • as a result of these factors there is a rise in serum unconjugated bilirubin in babies during the first few days after birth
3
Q

Describe the pattern that babies showing signs of physiological jaundice will follow

A
  • most babies will look yellow by day 3-4
  • as unconjugated bilirubin levels rise the serum albumin becomes saturated and then any excesses spills over into the blood plasma
  • unconjugated bilirubin is fat-soluble and so it will deposit in subcutaneous fat which makes the skin appear yellow
4
Q

Describe the role of the midwife when assessing physiological jaundice

A
  • act on any deviations from the norm
  • any baby who is visibly jaundiced should have SBR level checked (NICE 2010)
  • take a feeding history and check weight
  • identify if there are any risk factors for bilirubin encephalopathy or pathological jaundice