Neonatology Flashcards
Prevalence of jaundice in first week of life in neonates
60% of full term babies
80% of pre-term babies
Early jaundice (before 24h)
Unconjugated bilirubin
ALWAYS PATHOLOGICAL, almost always haemolysis
Haemolysis:
- ABO or Rh factor incompatibility
- Red cell shape abnormalities (e.g. spherocytosis)
- Red cell enzyme pathology (e.g. G6PD)
- Sepsis
- Non-haemolytical red cell destruction (polycythaemia, bruising or cephalhaematoma)
Physiological jaundice
Unconjugated
Due to immature liver unable to process and conjugate all the bilirubin
Exaggerated physiological response
Onset >24h
Should resolve within 2 weeks in a term baby (3 weeks in pre-term)
Breast milk jaundice
Prolonged unconjugated hyperbilirubinaemia
Jaundice peaks in second week, resolves very slowly and may last up to 3 months
Healthy, thriving infant
Due to factors in breast milk that increase enteric absorption of bilirubin
Can confirm by improvement of jaundice on temporary interruption of breastfeeding, but this is rarely required
Causes of conjugated hyperbilirubinaemia in neonate
ALWAYS PATHOLOGICAL - requires urgent work up Biliary atresia Neonatal hepatitis - congenital infection - alpha-1 antitrypsin deficiency - idiopathic Metabolic Choledochal cyst
What does yellow sclera indicate
unconjugated hyperbilirubinaemia
Likely causes of neonatal jaundice present at birth
Severe haemolysis
Hepatitis (unusual)
Likely causes of neonatal jaundice presenting within 48 hours of birth
Probably haemolysis
Likely causes of neonatal jaundice presenting after 10 days of life
Hypothyroidism
Biliary atresia
At what bilirubin level does jaundice become clinically apparent
85-120 micromol/L
Non-haemolytic causes of unconjugated hyperbilirubinaemia
Increased haem load: - haemorrhage (e.g. birth trauma) - polycythaemia - swallowed blood Increased enterohepatic circulation - Bowel obstruction or ileus - pyloric stenosis Impaired hepatic uptake and conjugation - Inborn errors of bilirubin metabolism (e.g. Gilbert's disease, galactosaemia) - Endocrine (hypothyroidism, hypopituitarism, drugs) - Inhibitors (breast milk) Mixed - asphyxia - Prematurity - Sepsis - Infants of diabetic mothers
Investigations in all jaundiced infants
Serum bilirubin ratio
CBE + film
Blood group
Coomb’s test
Investigations in systemically unwell jaundiced infants or those with early jaundice (in addition to general ones)
CRP Blood cultures EUC LFT VBG BGL
Investigations in infants with conjugated jaundice
LFT Clotting TFT Septic screen Viral serology Alpha-1 Antitrypsin levels Abdominal USS (+Discuss with gastroenterology team)
Treatment options for neonatal jaundice
Increase hydration (may reduce enterohepatic circulation of bilirubin)
Frequent breast feeding
Phototherapy (photo-isomerises bilirubin into water-soluble forms excreted directly into bile)
Exchange transfusion if bilirubin >340
IVIG if haemolytic disease and rising bilirubin despite phototherapy
Complications of neonatal juandice
Kinicterus:
Unconjugated only - toxic to brain cells - death and yellow staining (particularly grey matter)
Permanent clinical sequelae
Conjugated v unconjugated bilirubin
lipid- v water-soluble
Conjugated is water soluble - hence can be excreted in bile, urine, faeces
Unconjugated is lipid soluble - hence cannot be excreted, and is able to cross the blood brain barrier when not bound to albumin
Enzyme responsible for conjugation of bilirubin in the liver
Glucuronyl transferase (defective in Gilbert’s Disease)
What is the enzyme defective in Gilbert’s disease?
Glucuronyl transferase (responsible for the conjugation of bilirubin in the liver)
Time frame in which biliary atresia must be corrected
Must be corrected within 60 days of life`
Glucuronyl Transferase is defective in which disease
Gilbert’s disease
Causes of respiratory distress in the newborn (5)
Respiratory distress syndrome (Hyaline Membrane disease) Transient tachypnoea of the newborn Pneumonia Meconium aspiration syndrome Pneumothorax/Air leak
+other weird shit like diaphragmatic hernias that are rare and low yield
Definition of respiratory distress syndrome
When a neonate has difficulty breathing due to surfactant deficiency at birth. It is the dominant clinical problem faced by preterm infants
Risk factors for respiratory distress syndrome
Low gestational age
Maternal diabetes
Prenatal asphyxia
Multiple gestation
Clinical presentation of respiratory distress syndrome
Symptoms develop within 6 hours of birth
- grunting
- intercostal recession
- nasal flaring
- cyanosis
- increased oxygen requirement
Chest x-ray findings in respiratory distress syndrome
Diffuse reticulogrannular pattern (ground glass lungs)
Air bronchograms (dark air-filled bronchi made visible by opacification of surrounding alveoli)
Bell-shaped thorax
Hyperinflation excludes RDS unless patient is intubated
Natural history of respiratory distress syndrome
Presents within 6 hours of life
Progressive worsening over first 48-72 hours
Management of Respiratory distress syndrome
ABCs: - Lateral or prone position - Oxygen (warmed, humidified) - intubate (cynaosis, recurrent apnoea, resp failure [pH and pCO2) Thermoregulation Avoid enteral feeding Antibiotics (penicillin + gent after initial investigations) Surfactant administration if intubated