Differential diagnosis of bell-shaped (small) chest in neonates

Approach to the differential diagnosis of a bell-shaped (small) chest in neonates:

  • Oligohydramnios – due to pulmonary hypoplasia
  • Respiratory distress syndrome – due to pulmonary hypoexpansion
  • Neuromuscular paralysis – due to hypotonia causing body wall edema
  • Hydrops fetalis – due to third spacing causing body wall edema
  • Skeletal dysplasia (Asphyxiating thoracic dystrophy / Thanatophoric dysplasia) – due to short ribs