Respiratory distress syndrome

Dr Craig Hacking and Rishi Agrawal et al.

Respiratory distress syndrome (RDS) is a relatively common condition resulting from insufficient production of surfactant that occurs in preterm neonates. 

On imaging, the condition generally presents as bilateral and relatively symmetric diffuse ground glass lungs with low volumes and a bell-shaped thorax.

RDS is also known as hyaline membrane disease (not favored as reflects non-specific histological findings), neonatal respiratory distress syndrome, lung disease of prematurity (both non-specific terms), or as some authors prefer surfactant-deficiency disorder 2

The incidence is estimated at 6 per 1000 births 2

Respiratory distress presents in the first few hours of life in a premature baby. Symptoms include tachypnea, expiratory grunting, nasal flaring. The infant may or may not be cyanosed. Substernal and intercostal retractions may be evident. 

Risk factors include maternal diabetes, greater prematurity, prenatal asphyxia and multiple gestations.

Associated abnormalities are those that can occur in prematurity: germinal matrix hemorrhage, necrotizing enterocolitis, patent ductus arteriosus, delayed developmental milestones, hypothermia and hypoglycemia.

Immature type II pneumocytes cannot produce surfactant. The lack of surfactant increases the surface tension in alveoli causing collapse. Patients have a decreased lecithin: sphingomyelin ratio. Damaged cells, necrotic cells, and mucus line the alveoli.

  • typically gives diffuse ground glass lungs with low volumes and a bell-shaped thorax
  • often tends to be bilateral and symmetrical
  • air bronchograms may be evident
  • lung whiteout in severe cases
  • hyperinflation (in a non-ventilated patient) excludes the diagnosis
  • radiographs may show hyperinflation if the patient is intubated

RDS can be safely excluded if the neonate has a normal chest radiograph at six hours after birth. 

If treated with surfactant therapy there may be asymmetric improvement.

Exogenous surfactant administration. Supportive oxygen therapy.


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Article information

rID: 1467
Synonyms or Alternate Spellings:
  • Surfactant deficiency disease
  • Respiratory distress syndrome (RDS)
  • HMD
  • Infantile respiratory distress syndrome
  • RDS
  • Hyaline membrane disease
  • Surfactant deficiency disorder

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  • Case 1: complicated by pneumothorax
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