FRCA Notes

Neonatal Conditions

The intermediate curriculum is bursting with items on neonatal medicine, perhaps the most concise of which is to describe 'the special problems of the premature and ex-premature neonate'.

Resources

Persistent pulmonary hypertension of the new-born (PPHN)

  • There is, in essence, a persistent foetal circulation owing to high pulmonary pressures
  • This leads to right-to-left shunting:
    • The foramen ovale opens
    • Ductus arteriosus opens (R arm sats are better than leg sats)
  • There is consequent deterioration in cardiac function and cardiac failure

  • Often there is not a cardiac abnormality, but some other cause for the raised pulmonary pressures:
    • Intense pulmonary vasoconstriction e.g. from meconium, sepsis, hypoxia, acidosis
    • Arteriole hypertrophy e.g. from intra-uterine hypoxia
    • Abnormalities of the pulmonary vasculature e.g. congenital diaphragmatic hernia, pulmonary hypoplasia

  • The best management is avoidance of factors which may contribute (see above)
  • If present, treatment should be aggressive, with:
    • Oxygen
    • Fluids
    • Ventilatory support including surfactant
    • Cardiac support e.g. inotropy - dopamine often the inotrope of choice
    • Reducing PA pressure e.g. sildenafil, iNO, magnesium, adenosine
    • Some patients may require ECMO

Respiratory distress syndrome

  • An ARDS caused typically by prematurity due to surfactant deficiency
  • Best managed by ante-natal steroid prevention
  • Treatment involves:
    • Surfactant
    • CPAP
    • High-flow oscillatory ventilation

  • All pre-terms are at risk of shunt reversal and right-to-left shunting, especially those on high inotrope doses (i.e. dopamine >20μg/kg/min)

  • They have poor ɑ1-adrenoreceptor development and are less responsive to vasopressors
  • They have a flatter Frank-Starling curve and often respond well to fluid filling
  • They are prone to bradycardia in response to most things

  • Rule of thumb; target the MAP to gestational age in weeks

Retinopathy of prematurity

  • A disorder of abnormal vascularisation in the developing retinal vasculature
  • Higher risk if:
    • Retinal immaturity e.g. premature
    • Use of oxygen therapy; risk is associated with both the duration and degree of oxygen therapy and a PaO2 <10kPa should be targeted
    • Other coalescing illness
  • Treatment is immediate cryo/LASER ablation under GA

Others

  • Intraventricular haemorrhage
  • Hydrocephalus
  • Seizures

Bowel wall defects

  • Gastroschisis
    • A common, lateral muscle wall defect
    • Not typically associated with other abnormalities

  • Exomphalos
    • Herniation through the umbilicus
    • Associated with other midline abnormalities including VSD, neural tube defects, bladder extrophy

  • Management includes covering the bowel, rehydration, use of a silo (gastroschisis) and early surgery

Bowel obstruction

  • Congenital diaphragmatic hernia
  • Tracheo-oesophageal fistula
  • Pyrloric stenosis
  • Hirschsprung's disease
  • Meconium ileus from inspissated meconium e.g. in cystic fibrosis
  • Malrotation
  • Intussusception - often occurs at a particular locus e.g. Meckel's diverticulum, a large lymph node
  • Atresia (oesophageal, duodenal, distal)