Learning Radiology xray montage

Meconium Aspiration Syndrome

  • Most common cause of neonatal respiratory distress in full-term/postmature infants
    • Hyaline membrane disease most common cause in premature infants

  • Etiology

    • Fetal circulatory accidents/placental insufficiency /postmaturity result in perinatal hypoxia and fetal distress
    • Meconium defecated in utero triggered by vagal response 

  • Pathogenesis

    • Meconium products produce bronchial obstruction and air-trapping
    • Chemical pneumonitis

  • Incidence

    • 10% of all deliveries have meconium-stained amniotic fluid
    • 1% of all deliveries have respiratory distress

  • Clinical findings

    • Cyanosis (rare)
    • Large infant
    • Meconium staining

  • Imaging findings

    • Bilateral diffuse grossly patchy opacities (atelectasis and consolidation)
    • Hyperinflation of lungs
    • Areas of emphysema (air-trapping)
    • Spontaneous pneumothorax and pneumomediastinum
      • 25% requiring no therapy
    • Small pleural effusions (20%)
    • No air bronchograms
    • Rapid clearing usually within 48 hours

Meconium Aspiration Syndrome. Frontal chest shows large, ropey and strand-like densities in
a post-mature infant consistent with Meconium Aspiration Syndrome

  • Treatment

    • Supportive
      • Antibiotics and oxygen
      • ECMO can be used

  • Complications

    • Morbidity from anoxic brain damage is high