Neonatal Respiratory Distress

Question 1

Describe a differential diagnosis for a neonate in respiratory distress

Answer 1

• Pulmonary
  
  • ƒƒRespiratory distress syndrome (RDS)
  • ƒƒTransient tachypnea of the newborn (TTN)
  • ƒƒMeconium aspiration syndrome (MAS)
  • ƒƒPleural effusions, pneumothorax
  • ƒƒCongenital lung malformations
• Infectious
  
  • ƒƒSepsis, pneumonia
• Cardiac
  
  • ƒƒCongenital heart disease (cyanotic, acyanotic)
  • PPHN
• Hematologic
  
  • ƒƒBlood loss, polycythemia
• Anatomic
• Metabolic
  
  • ƒƒHypoglycemia
  • Acidaemias
• Neurologic
  
  • ƒƒCNS damage (trauma, hemorrhage)

Question 2

What is the definition of neonatal respiratory distress?

Answer 2

• Tachypnoea > 60 per minute (also often tachycardia)
• Increased effort (flaring, intercostal retraction, accessory muscles, paradoxical breathing))
• Noisy breathing (groaning/grunting)
• Central cyanosis

Question 3

What causes wet lung syndrome (TTN)? Which neonates tend to get it? What are the CXR features?

Answer 3

• Due to continued fluid production or decreased/delayed removal
• Risk factors
  
  • Term, male, macrosomic, maternal diabetes, LUSCS (no lung squeezing)
• Diagnosis: exclusion
• On CXR: perihilar infiltrates, fluid in fissures
• Generally resolves within 24 hours

Question 4

What causes meconium aspiration syndrome? What are the risk factors? The CXR features? How is it prevented?

Answer 4

• Risk factors: post-dates, obstructed labour, mec liquor
• Blocks airways to varying degrees - causes a pneumonitis
• Requires suction below vocal cords
• On CXR - over-distention/atelectasis/consolidation
• Prevention - of post-maturity, asphyxia; ensure adequate suctioning

Question 5

What causes hyaline membrane disease (RDS)? What are the risk factors? The CXR features? How is it treated?

Answer 5

• Lack of surfactant production (surge at 34-35 weeks)
• Risk factors - prematurity, asphyxia, maternal diabetes, male, FHx, CS (no squeezing of lungs during delivery)
• Ground-glass appearance on CXR, may resemble pneumonia
• Treatment: surfactant, maintain respiration/ventilate

Question 6

What might help you distinguish between respiratory distress syndrome, transient tachypnoea of the newborn and meconium aspiration syndrome?

Answer 6

• CXR
  
  • RDS - ground glass appearance
  • TTN - fluid in fissures
  • MAS - patchy consolidation/atelectasis
• Risk factors
  
  • RDS - pre-term, LUSCS
  • TTN - term, LUSCS
  • MAS - post-dates, mec liquor

Question 7

What is the pathophysiology of persistent pulmonary hypertension of the newborn? What needs to be excluded?

Answer 7

• High resistance pulmonary vessels fail to fall to low pressure (e.g. shunting)
• Risk factors: MAS, RDS, congenital heart disease (requires echo to exclude)