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child health > neonatal jaundice > Flashcards

neonatal jaundice Flashcards

1
Q

what is jaundice?

A

-yellow discolouration of skin and sclera due to high levels of bilirubin

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2
Q

how does jaundice tend to appear on neonates?

A

cephalopods-caudal progression (face to feet)

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3
Q

True/ False Jaundice is physiologically normal in babies

A

True

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4
Q

how is bilirubin produced?

A
  • from the breakdown of red blood cells and is produced from heme
  • heme breakdown produces unconjugates bilirubin which mostly circulates bound to albumin
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5
Q

how does bilirubin travel in the body?

A
  • unconjugated bilirubin circulates bound to albumin

- some bilirubin is free in plasma and can pass across the blood brain barrier

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6
Q

is unconjugated bilirubin water soluble or insoluble?

A

insoluble and so most be metabolised in the liver into conjugated bilirubin which is water soluble to be excreted from the gut

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7
Q

is conjugated bilirubin insoluble or soluble in water?

A

soluble and so unconjugated bilirubin which is insoluble must be metabolised into soluble conjugated bilirubin which can be excreted from the gut

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8
Q

what does liver metabolism rely on?

A

-bilirubin uptake via ligandin and then conjugation by uridine diphosphoglucuronyltransferase (UDPGT)

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9
Q

what are the levels like of ligandin and UDPGT in a newborn and what effect does this have?

A

ligandin=low
UDPGT=low

this means there is less uptake of bilirubin into the liver and so are inefficient at managing bilirubin

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10
Q

what is enterohepatic circulation?

A

-some newborns revert to unconjugated bilirubin and is recirculated into the blood stream

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11
Q

what enzyme abnormalities may affect bilirubin metabolism?

A

Gilberts disease

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12
Q

what causes Gilberts disease?

A

mutation in UGT1A1 gene

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13
Q

what effect does Gilberts disease have?

A

-reduces bilirubin uridine diphosphate glucuronosyltransferase (bilirubin-UGT) by around 30% and can make jaundice worse

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14
Q

What can high levels of unconjugated bilirubin cause?

A

-can cross the BBB and cause encephalopathy which can lead to Kernicterus (cerebal palsy related to bile)

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15
Q

when does physiological jaundice appear in neonates?

A

24-72 hours

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16
Q

when does early jaundice appear in neonates?

A

0-24 hours

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17
Q

when does late jaundice appear in neonates?

A

> 14 weeks in term and 21 days pre term

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18
Q

what are some causes of pathological jaundice?

A
  • haemolysis
  • sepsis
  • metabolic disorders
  • liver disease
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19
Q

what causes physiological jaundice in neonates?

A
  • increased production of bilirubin
  • foetal RBC have less of a lifespan than adults (2/3rds of an adult)
  • babies born with high hematocrit (proportion of red blood cells in their blood)
  • babies are often bruised
  • decreased uptake and binding of bilirubin in liver cells leading to decreased conjugation (most important)
  • increased enterohepatic circulation of bilirubin
20
Q

is it normal for a baby to jaundice <24 hours of age?

A

no- it is almost always pathological

21
Q

what causes early jaundice?

A
  • usually due to haemolysis with excessive production of bilirubin
  • can be sepsis or infection

Rarer causes:

  • other blood grop incompatibilities
  • red cell enzyme defects e.g. G6PD deficiency
  • red cell membrane defecrs e.g. hereditary spherocytosis
  • hepatitis
22
Q

what can cause a baby to be born jaundiced?

A
  • severe haemolysis

- hepatitis (unusual)

23
Q

what may cause haemolysis?

A
  • ABO incompatibility
  • Rh immunisation
  • sepsis
24
Q

what is ABO incompatibility?

A
  • a disease that causes haemolysis and so jaundice

- happens when the mothers blood type is O, and her baby’s blood type is A or B

25
Q

when should hepatitis be considered as a reaon for causing early jaundice?

A

-if there is substantial elevation of conjugated bilirubin (>15% of the total)

26
Q

what are investigations of early jaundice?

A
  • total bilirubin concentration (SBR)
  • maternal blood group and antibody titres (if Rh negative)
  • baby’s blood, Direct Agglutination Test (detects antibodies on the baby’s red cells), the eulation test to detect anti-A or anti-B antibodies on baby’ red cells
  • FBC, CRP
  • if clinical concern measure conjugated bilirubin
27
Q

what investigations should be done for suspected haemolysis?

A
  • blood group incompatibility (most commonly Rhesus or ABO incompatibility)
  • can occur in sepsis but it is rare
  • can be due to Glucose 6 phosphate dehydrogenase deficiency
28
Q

what tests must be done for suspected haemolysis?

A

Direct Agglutination test (DAT):

  • Blood group incompatibilities (most commonly Rhesus or ABO incompatibility) can be identified with a positive DAT
  • Sepsis would test negative on DAT

Check infants blood group for comparison with mothers

29
Q

what test would be done to test for blood group incompatibility such as Rhesus or ABO incompatibility?

A

Direct Agglutination Test (DAT) and it would be positive

30
Q

how does bilirubin cause encephalopathy?

A

it crosses the blood brain barrier (BBB) and affects the brain

31
Q

how does bilirubin encephalopathy present in neonates?

A
  • lethargy
  • poor feeding
  • temperature instability
  • hypotonia
  • arching of the head, neck and back
32
Q

what may cause serum bilirubin to be too high causing jaundice?

A
  • mild dehydration/insufficient milk supply
  • breakdown of extravasated blood e.g. cephalohaematoma, bruising
  • some ‘normal’ physiological
  • haemolysis (continuing causes as discussed under too early)
  • infection
  • increased enterohepatic circulation (gut obstruction)
33
Q

what is the major differential in diagnosis of ‘too long’ pathological jaundice?

A

-whether the elevated bilirubin is mostly unconjugated or whether the conjugated fraction is substantially increased (>15% of total)

34
Q

what is the most common cause of unconjugated prolonged jaundice?

A

breast milk jaundice (cessation of breast feeding is not advised)

35
Q

what are some causes of persistent unconjugated hyperbilirubinemia causing jaundice?

A
  • breast milk jaundice (most common)
  • poor milk intake
  • haemolysis
  • infection (especially UTI)
  • hypothyroidism
36
Q

True or false conjugated hyperbilirubinaemia can be normal

A

False- it is always abnormal

can be hepatitis or biliary atresia

37
Q

what does conjugated hyperbulirubinaemia suggest?

A

always abnormal

could be biliary atresia or hepatitis

38
Q

what is biliary atresia?

A

-a rare disorder causing obstructive jaundice which is fatal if left untreated

39
Q

how do patients with biliary atresia present?

A
  • usually have pale clay coloured wstool
  • dark urine
  • jaundiced
40
Q

what is the treatment for biliary atresia?

A

-surgery with a Kasai portoenterostomy before 3 months of age

41
Q

what is the success of the biliary atresia surgery directly related to?

A

-age of operation

<10 weeks= better chance of bile flow and reduced need for liver transplant

42
Q

what is the most common causes of unconjugated hyperbilirubinaemia?

A
  • hypothyroidism (most common)

- breast milk jaundice

43
Q

what is done to detect hypothyroidism that causes unconjugated hyperbilirubinaemia early?

A

babies are screened for hypothyroidism

44
Q

what is the treatment for jaundice?

A
  • treat underlying cause if present
  • adequate enteral feeding/hydration
  • if breast feeding is not established then top up feeds with expresed breast milk is best
  • sometimes supplementation with formula will be needed
  • occasionally some tube feeding will be required and for seriously unwell babies intravenous fluids
  • phototherapy (blue-green range light, make sure eye protection)
  • rarely must do an exchange transfusion (usually required for babies with Haemolytic disease)
  • IV immunoglobulin (used when bilirubin is increasing even in phototherapy)
45
Q

what treatment is often required to treat jaundice in babies with haemolytic disease?

A

-exchange transfusion

46
Q

what is normal weight loss in neonates?

A

up to 10%

child health (28 decks)

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