Neonatal jaundice Flashcards
What is jaundice?
Clinical sign - Yellow colouration of skin and sclerae due to accumulation of bilirubin
Normal factors in the neonate that make them more susceptible to jaundice
- Neonates: high haematocrit / RBC volume; shorter life span of RBC (70 -90 days)
- High bilirubin production
- Slow bilirubin clearance
- Immature hepatic glucuronyl transferase
- High beta glucoronidase (increased bilirubin re-absorption)
- Absent colonic bacteria
Why neonates more susceptible to developing kernicterus?
BBB permeable to bilirubin for first 10-14 days of life
Features of acute bilirubin encephalopathy
Lethargy, poor feeding, high pitched cry
Opisthotonus, seizures
Features of chronic bilirubin encephalopathy
- Kernicterus - histological accumulation of pigment in basal ganglia
- BIND (bilirubin induced neurological dysfunction) - subtle intellectual impairment
Clinical features of Kernicterus
Athetoid cerebral palsy
Hearing loss
Paralysis of upward gaze
Criteria for pathological jaundice
- Any increase in conjugated bilirubin
- Early jaundice: before 24 hours of life
- Extremely high
- Prolonged
Criteria suggesting physiological jaundice
- Elevated unconjugated bilirubin
- TSB generally peaks at about 100umol/L on day 3-4 and then declines to adult levels by day 10 (Asian infants peak at higher values)
- Exaggerated physiologic (up to 290umol/L)
How is a diagnosis of physiological jaundice made?
Never appears in first 24 hours of life
Diagnosis of exclusion in active, well fed and are not ill.
TSB usually not >200umol/l (275 in breastfed)
What is breastmilk jaundice?
Prolonged unconjugated physiological jaundice in a breast fed newborn
Good growth/ weight
?beta-glucuronidase increases enterohepatic circulation?
What does beta-glucuronidase do?
Deconjugates glucuronic acid causing more bilirubin to be re-absorbed in the small intestine.
Causes of an unconjugated pathological jaundice in the neonate
- Breast feeding jaundice
- Haemolysis
- Internal haemorrhage
- Polycythaemia
- Infant of diabetic mother
- Hypothyroidism
- Rare (Crigler-Najjar, Gilbert syndrome)
Causes of a conjugated pathological jaundice in the neonate
- Congenital infections (CMV, syphilis, herpes, rubella)
- Hepatitis (TPN, viral)
- UTI
- Sepsis
- Rare: biliary atresia, cystic fibrosis, inborn errors of metabolism
What is breastfeeding jaundice?
Poor breastfeeding - dehydration and weight loss.
Delayed GIT bilirubin clearance = more re-absorption
Treatment of breastfeeding jaundice
Rehydration and more frequent feeding
Causes of heamolysis in the neonate
Common
- Blood group incompatibility: haemolytic disease of the newborn (ABO, Rhesus, minor antigens)
- Infections / sepsis
Rare:
- Haemoglobinopathy (thalassaemia)
- RBC enzyme deficiency (glucose 6 phosphatase deficiency, pyruvate kinase deficiency)
- RBC membrane defects (spherocytosis, ovalocytosis)
Causes of heamorrhage in the neonate
Common
- Bruising (traumatic delivery / resuscitation)
- Pre term / NVD
- Vaginal breech
- Cephalhaematoma, subaponeurotic haemorrhage
Rare
- Internal haemorrhage
Most common cause of heamolytic disease of the newborn
ABO incompatibility
ABO incomatibility pathophysiology
Maternal blood group O has IgG against A and B antigens. If child has A or B then they develop mild haemolysis. Once born placenta can no longer remove bilirubin. Therefore, accumulates.
How do we diagnose ABO incompatibility?
All children born to group O mothers have TSB measured at 8 hours. If TSB > 80umol/l then phototherapy started and grouping and Coombs test is performed.
What must the resus status of the mother and father be to get Rh disease of the newborn?
Mother = negative Father = positive
What are the major threats to the Rh diseased infants life?
Profound anaemia
Respiratory distress, cardiac failure
Bilirubin encephalopathy
Features of severe Rh disease
Massive extra medullary haematopoiesis
Hydrops fetalis
IUD
Why is jaundice not always seen at birth in Rh disease?
Placenta can remove excess biliruin
How is Rh disease prevented?
IM anti-D immunoglobulin given to Resus negative woman within 72 hours following: Delivery Miscarriage Amniocentesis APH ECV
Clinical features of Rh disease
Pale large placenta Anaemia Jaundice (rapid onset) HSM Oedema Blueberry muffin rash
Rx for Rh disease
Resuscitate (Respiratory, metabolic disturbances)
Phototherapy (Start immediately, TSB every 2-4 hours)
Exchange transfusion (If cord TSB >120/ HB <30%)
Straight blood transfusion
IV immunoglobulin
How does phototherapy work?
Bilirubin converted to metabolically inert, water soluble Lumiruin by blue light
Side effects of phototherapy
- Hyper / hypothermia
- Skin rashes
- Diarrhoea
- Maternal anxiety / bonding
What are the indications for exchange transfusion?
Cord TSB > 120 Cord Hb < 10 PCV < 30 % Hydrops fetalis Phototherapy failure Signs of bilirubin encephalopathy
What TSB level correlates to recognition of clinical jaundice?
> 70 umol/l
Causes of prolonged jaundice
Breastmilk jaundice
Hypothyroidism
Galactosaemia
Hepatitis