Neonatology Flashcards
Neonatal jaundice occurs in ______ of term infants and _____ of preterm infants
Unconjugated bilirubinaemia may be ________________
Conjugated bilirubinaemia is ________________
High levels of bilirubin have ________________________________________________
- Neonatal jaundice occurs in 60% of term infants and 80% of preterm infants
- Unconjugated hyperbilirubinemia may be physiological or pathological
- Conjugated hyperbilirubinaemia will always be pathological
- High levels of bilirubin have harmful effects on the baby causing kernicterus (brain damage associated with bilirubin), can cause a form of cerebral palsy, hearing loss, problems with vision and teeth as well as intellectual disabilities
Describe physiological jaundice?
- Jaundice in a healthy baby, born at term is normal and may result from:
- Increased RBC breakdown (HbF being broken down as now making HbA)
- Immature liver struggles to process high bilirubin concentrations
- Physiological jaundice starts at days 2-3 and peaks day 5 but should resolve by day 10, the baby is well and does not need intervention
4 categories of pathological jaundice?
Haemolytic disease (e.g. rhesus, ABO incompatibility, G6PD deficiency)
* This has an onset of less than 24 hours
* Jaundice that comes on in less than 24 hours is always pathological
Physiological jaundice can progress to pathological jaundice if the baby is premature or there is increased red cell breakdown e.g. extensive bruising or cephalohematoma following instrumental delivery or baby is dehydrated due to poor feeding
Unwell neonate
* Jaundice may be a sign of congenital or post-natal infection
Prolonged Jaundice
* Jaundice for more than 14 days in term and 21 in preterm should raised suspicion of infection, hypothyroidism, hypopituitarism, galactosaemia, breast milk jaundice (this goes away on its own), choledhocal cyst or biliary atresia
Investigations in neonatal jaundice?
- All infants are assessed for jaundice with the naked eye under natural light at newborn screening – babies who are not jaundiced do not need further testing
- If it is thought a baby has jaundice it can be tested for using a transcutaneous bilirubinometer (this is like a torch device that measures bilirubin levels)
- Blood tests would be done if reading very high or jaundice before 24 hours or after 14 days
- Other tests depend on what you think underlying cause is
Management of neonatal jaundice?
- Bilirubin levels are interpreted using treatment threshold graphs that are gestation specific and determine management for hyperbilirubinaemia
- Babies either have blue light phototherapy or if very bad hyperbilirubinaema an exchange transfusion
- Also need to treat any underlying cause e.g. surgery for biliary atresia
What is biliary atresia?
- Absence/ obstruction of the extrahepatic bile ducts
- Congenital defect or inflammation soon after birth which causes destruction of the bile ducts
- Mechanism not really known
Presentation of biliary atresia?
- Presents in the first few weeks of life
- Persistent jaundice (if jaundice for > 14 days you should consider this as a diagnosis)
- Pale stools
- Dark urine
Investigations for biliary atresia?
- LFTs are abnormal with a conjugated hyperbilirubinaemia
- US is initial imaging
- Liver histology and biopsy is usually diagnostic method of choice
- ERCP is sometimes needed
Management of biliary atresia?
- Kasai procedure is initial management
- Most babies with biliary atresia will go on to need a liver transplant in childhood
As you get older HR and RR _____ and BP _______
HR and RR get lower as you get older, BP gets higher
Normal neonatal HR and RR?
HR - 120-140/60 (neonates closer to 160)
RR - 40 -60
Explain fetal circulation?
- Oxygenated blood is supplied by the umbilical vein
Some of that blood is directed to the ductus venous (shunts blood to IVC) and then IVC and some enters the liver
Blood goes from IVC to RA and most goes RA to LA through foramen ovale
This blood goes to LV and supplies carotids and ascending aorta
Some of the blood from the RA enters RV and is pumped into PA
In fetus the PA and aorta are connected by the ductus arteriosus which directs most of the partially oxygenated blood away from the lungs and to the lower body - Two umbilical arteries that come off the iliacs of the fetus and deoxygenated blood back to Mum
What does the ductus venosus do?
Allows some of the oxygenated blood from the umbilical vein to bypass the liver
What is the purpose of the fetal circulation?
makes sure most of the oxygenated blood reaches the brain, because the lungs aren’t working you dont want all the blood to go though there, only enough oxygenated blood to keep the lungs oxygenated as opposed to all the blood going to the lungs to be oxygenated
What is the ductus arteriosus and its purpose?
- In fetus the PA and aorta are connected by the ductus arteriosus which directs most of the partially oxygenated blood away from the lungs and to the lower body
Fetal circulation adaption at birth?
- Pulmonary vascular resistance drops (because the lungs are not full of fluid), systemic vascular resistance rises, oxygen tension rises, circulating prostaglandins drop, ductus arteriosus constricts, foramen ovale closes
- The ductus arteriosus should close in 2-3 days after birth
- In some people the foramen ovale does not close, some people will have this and not know, generally doesn’t cause complications
- In some infants can get patent ductus arteriosus which tends to cause more problems as oxygen poor blood is not flowing correct way
Explain what transient tachypnoea of the newborn and any treatment/ prognosis?
- This is a diagnosis of exclusion and presents with a baby grunting shortly after delivery with rapid breathing and fluid on XR
- Basically, it occurs in big healthy babies born by section who haven’t had the stress of delivery to squeeze excess fluid out of the lungs
- This generally doesn’t need any treatment
Describe reflexes you check in a newborn exam?
- Reflexes you check for in newborn exam
- Moro/ startle reflex: Loss of support for baby’s neck causes it to spread out arms
- Rooting and sucking reflex: stroking baby’s cheek it start to suck, baby sucks if put finger in mouth
- Grasp: baby grasps finger if put it in palm
- Stepping: baby appears to take steps with feet when upright
Explain what hemorrhagic disease of the newborn is and what we do to reduce the risk?
- Babies have low stores of vitamin k at birth and this increases their risk of bleeding
- All babies are given an injection of vitamin K at birth to reduce their risk
Define preterm and different extents?
- Preterm is any baby delivered before 37 weeks completed gestation
- Extremely preterm is before 28 weeks
- Very preterm is 28-32 weeks
- Moderate to late preterm is 32 to 27 weeks
List 8 risk factors for preterm delivery?
- Previous preterm delivery
- Multiple pregnancy
- Smoking and illicit drug use in pregnancy
- Being under or overweight in pregnancy
- Early pregnancy (within 6 months of previous pregnancy)
- Problems in pregnancy e.g. cervix, uterus, placenta or infection
- Certain chronic conditions e.g. diabetes and hypertension
- Physical injury or trauma
Explain what RDS/ PPHN is?
- This occurs in premature babies due to surfactant deficiency as surfactant isn’t produced until late on in pregnancy
- This results in the baby having too high surface tension in the lungs
- Presents with tachypnoea, grunting, upper intercostal recession, nasal flaring and cyanosis
- The baby’s condition will worsen over time
