Revision - Neonatal Jaundice, Sepsis, Prematurity Flashcards
1st line abx for suspected or confirmed early onset neonatal sepsis?
IV benzylpenicillin + gentamicin
What should be measured 18–24 hours after neonatal sepsis presentation in babies given antibiotics?
CRP
How long are Abx continued for in neonatal sepsis if:
a) blood cultures are positive
b) CSF is positive
a) 7-10 days
b) 14 days
1st line Abx for suspected or confirmed LATE onset neonatal sepsis?
IV flucloxacillin (or vancomycin) + gentamicin
What Abx are given if meningitis is suspected in neonates?
IV cefotaxime + amoxicillin
Early vs late onset neonatal sepsis?
Early: <72h after birth
Late: >72h - 28 days after birth
What is the most common bacteria causes late onset neonatal sepsis?
Coagulase negative Staphylococci
e.g. Staph epidermis (colonises lines)
What are 2 ABSOLUTE contraindications to lumbar puncture in neonates?
1) GCS <8
2) Signs of raised ICP
Note - a bulging fontanelle alone, without other signs of raised ICP, is not a contraindication.
What are 2 metabolites of conjugated bilirubin?
1) Stercobilinogen
2) Urobilinogen
Is physiological jaundice conjugated or unconjugated?
Unconjugated
Give 3 haemolytic causes of neonatal jaundice
1) Haemolytic disease of the newborn –> ABO or rhesus incompatibility
2) G6PD deficiency
3) Hereditary spherocytosis
What is hereditary spherocytosis?
An inherited disease where defects in RBC skeletal proteins cause RBCs to assume a spherical shape with a reduced lifespan.
Inheritance of G6PD deficiency?
X-linked recessive
What happens in G6PD deficiency?
A lack of G6PD makes RBCs susceptible to oxidative damage and haemolysis. It can cause severe neonatal jaundice.
Give 4 endocine or metabolic causes of unconjugated neonatal jaundice
1) Gilbert’s syndrome
2) Crigler-Najjar syndrome
3) Congenital hypothyroidism
4) Galactosaemia and other inborn errors of metabolism (these may also cause conjugated jaundice)
Inheritance of Gilbert’s syndrome?
Autosomal recessive
What happens in Gilbert’s syndrome?
There is reduced activity of UGT in the liver.
This causes reduced ability to conjugate bilirubin, resulting in mild episodes of jaundice throughout life in response to certain triggers.
Inheritance of Crigler-Najjar syndrome?
Autosomal recessive
What happens in Crigler-Najjar?
NO functioning UGT is produced in the liver.
It presents with severe, prolonged jaundice that often results in neurological damage and death within one year of life.
What are 2 causes of conjugated neonatal jaundice?
1) Biliary atresia
2) Neonatal hepatitis (e.g. CMV, hepatitis B, rubella or HSV)
What is a common cause of neonatal jaundice within the first 24 hours?
Neonatal sepsis
What does ‘rhesus’ refer to?
Various types of rhesus antigens on the surface of RBCs.
These antigens vary between individuals.
The rhesus antigens are SEPARATE to the ABO blood groups.
What is the most relevant antigen within the rhesus blood group system?
Rhesus-D antigen
Do women who are rhesus-D positive need any additional treatment during pregnancy?
No
What do you need to consider when a woman who is rhesus-D negative becomes pregnant?
The possibility that her child will be rhesus positive.
Why is it an issue if a rhesus-D negative woman is pregnant with a rhesus-D positive baby?
1) As it is likely at some point in the pregnancy (i.e. childbirth) that the blood from the baby will find a way into the mother’s bloodstream.
2) When this happens, the baby’s RBCs display the rhesus-D antigen.
3) The mother’s immune system will recognise this rhesus-D antigen as foreign, and produce antibodies to the rhesus-D antigen.
4) The mother has then become sensitised to rhesus-D antigens.
5) Usually, this sensitisation process does not cause problems during the first pregnancy.
6) During subsequent pregnancies, the mother’s anti-rhesus-D antibodies can cross the placenta into the fetus.
7) If that fetus is rhesus-D positive, these antibodies attach themselves to the RBCs of the fetus and causes the immune system of the fetus to attack them (haemolysis).
8) The RBCl destruction caused by antibodies from the mother is called haemolytic disease of the newborn.
When can the sensitisation process in a rhesus D negative mother be a problem in their first pregnancy?
If the sensitisation happens early on, such as during antepartum haemorrhage
Is maternal diabetes a risk factor for neonatal jaundice?
Yes
What is biliary atresia?
Congenital inflammatory condition.
Results in complete obliteration of extra-hepatic ducts after birth –> cirrhosis –> death.
How does biliary atresia present?
1) prolonged conjugated jaundice
2) pale stools
3) dark urine
What defines prolonged neonatal jaundice?
> 14 days in term babies
> 21 days in preterm babies
What is the gold standard diagnostic method for biliary atresia?
Percutaneous biopsy
Management of biliary atresia?
1) portoenterostomy (Kasai procedure)
or
2) liver transplant
What investigations are required in prolonged neonatal jaundice?
1) conjugated and unconjugated bilirubin levels
2) direct antiglobulin test (Coombs’ test): for haemolysis
3) TFTs
4) FBC and blood film: for polycythaemia or anaemia
5) urine for MC&S and reducing sugars
6) U&Es and LFTs
7) G6PD levels for G6PD deficiency
Causes of prolonged neonatal jaundice?
1) Hypothyrodism
2) Biliary atresia
3) Galactosaemia
4) Breast milk jaundice
5) Prematurity
6) UTI
7) Congenital infections e.g. CMV, toxoplasmosis
Which neonates require routine bilirubin checking?
All babies who are visibly jaundiced
What are 2 options for measuring bilirubin levels in neonates?
1) Transcutaneous bilirubinometry
2) Serum bilirubin
When would transcutaneous bilirubinometry be used to over serum bilirubin and vice versa?
Transcutaneous bilirubinometer:
- >35 weeks gestation
- >24 hours old
- Can be used for all subsequent measurements, providing the level remains <250 µmol/L and the child has not required treatment
Serum bilirubin:
- Babies who are visibly jaundiced <24 hours of life
- Gestational age <35 weeks
- Monitoring bilirubin after starting treatment.
What bilirubin monitoring is required in babies with jaundice <24h after birth?
Serum bilirubin
Which investigation is used to monitor bilirubin levels AFTER starting treatmnet?
Serum bilirubin
Which investigation is used to monitor bilirubin levels in jaundiced neonates with a gestational age <35 weeks?
Serum bilirubin
Purpose of a blood packed cell volume (PCV) in neonatal jaundice?
To assess the degree of anaemia or polycythaemia
What does a positive Coombs test indicate?
Suggests immune-mediated haemolysis (i.e. haemolytic disease of the newborn).
What does a negative Coombs test indicate?
suggests non-immune-mediated haemolysis (e.g. hereditary spherocytosis or G6PD deficiency)
What is neurotoxic unconjugated bilirubin converted to in phototherapy?
Lumirubin (water-soluble isomer which is readily excreted in the bile and urine).
What is found on a treatment threshold charts for neonatal jaundice?
Age of baby - x axis
Total bilirubin level - y axis
How often should bilirubin levels be monitored during treatment for neonatal jaundice?
Repeat bilirubin 4-6 hours post initiation to ensure not still rising, 6-12 hourly once level is stable or reducing.
When can phototherapy for neonatal jaundice be stopped?
Stop phototherapy once level >50µmol/L below treatment line on the threshold graphs.
Check for rebound of hyperbilirubinaemia 12-18 hours after stopping phototherapy.
What should you check for 12-18h after stopping phototherapy?
rebound hyperbilirubinaemia
What can be used as adjunct to intensified phototherapy in rhesus haemolytic disease or ABO haemolytic disease?
IV immunoglobulin
What is the key complication of neonatal jaundice?
Kernicterus (bilirubin encephalopathy)
How does bilirubin encephalopathy (kernicterus) present?
- lethargy
- hypotonia
- poor suck reflex
This progresses to:
- hypertonia
- opisthotonos
- fever
- seizures
- a high-pitched cry
Long term complications of kernicterus?
- cerebral palsy
- sensorineural hearing loss
- cognitive impairment
1st line investigation in suspected pathological neonatal jaundice?
Coombs test
When are doses of anti D given?
1) 28 weeks gestation
2) Within 24 hours of birth
If the Coombs test is negative in neonatal jaundice, what is the next step?
Check Hb level
Low –> may be a blood collection outside vessels e.g. cephalohaematoma due to trauma during delivery.
High –> increased load of RBCs is slowly getting broken down e.g. common in babies of diabetic mothers, twin-twin transfusion syndrome, delayed cord clamping.
If Hb is normal in neonatal jaundice, what is next step?
Check reticulocyte count, LDH & haptoglobin.
Then consider blood film.
Define preterm birth
<37 weeks gestation
Define:
1) extreme preterm
2) very preterm
3) moderate to late preterm
1) <28w
2) 28-32w
3) 32-37w