Transient tachypnoea of the newborn (TTN), also known as retained fetal fluid or wet lung disease, presents in the neonate as tachypnoea for the first few hours of life, lasting up to one day. The tachypnoea usually resolves by within 48 hours.
TTN is one of the commonest causes of neonatal respiratory distress, particularly in term or near term newborns. It is estimated to effect 1-2% of all neonates with an equal gender predilection.
Infants present in respiratory distress, classically with grunting and nasal flaring, within the first six hours of life. There can be mild cyanosis present.
Amniotic fluid is normally expressed from the lungs during vaginal delivery and then absorbed after birth. In TTN there is build-up of fluid in the lungs thought due to the reduced mechanical squeeze and reduced capillary and lymphatic removal of amniotic fluid. This reduced clearance of fluid from the lungs is why some have proposed it is more commonly seen in Caesarean section deliveries since the thoracic compression that would occur in a normal vaginal delivery does not take place.
- interstitial oedema - prominently perihilar
- often seen as perihilar streakiness
- pleural effusions that are usually small
- mild to moderate cardiomegaly has been described rarely
- severe cases may have perihilar alveolar opacities
- normal chest radiograph by 48-72 hours post-partum
congenital heart disease
- heart size is usually normal in TTN and there is rapid spontaneous resolution
- neonatal pneumonia
- persistent fetal circulation
- hyaline membrane disease: lung volumes are slightly decreased in HMD but are normal to slightly hyperinflated TTN
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- neonatal lines and tubes
- neonatal respiratory distress (causes)
- neonatal chest x-ray (an approach)
- neonatal chest pathology