Imaging in Transient Tachypnea of the Newborn
- Author: Margarita Asenjo, MD; Chief Editor: John Karani, MBBS, FRCR more...
Overview
Transient tachypnea of the newborn appears soon after birth and has been identified as occurring with cesarean birth and infant sedation.[1, 2, 3, 4] Longer labor intervals, macrosomia of the fetus, and maternal asthma also have been associated with a higher frequency of transient tachypnea of the newborn. It may be accompanied by chest retractions, by expiratory grunting, or by cyanosis (which can be relieved with minimal oxygen.) Recovery is usually complete within 3 days.[5, 6]
Radiologically, this syndrome frequently is termed wet lung disease. In the medical literature, discussions concerning transient tachypnea of the newborn can also be found under the following names: retained fetal lung liquid, retention of fetal lung fluid, respiratory distress syndrome type II, transient respiratory distress of the newborn, and neonatal retained fluid syndrome.
The lungs usually are affected diffusely and symmetrically, and the condition is commonly accompanied by a small pleural effusion.[7, 8] The clinical course of transient tachypnea is relatively benign when compared with the severity suggested by chest films. Radiographic resolution by the second or third day characterizes this entity and differentiates it from other possible disorders; if radiographic resolution is not complete by the third day or if respiratory symptoms persist longer than 5 days, an alternative diagnosis should be sought (see Differential diagnosis and other problems to be considered, below).
Radiograph of a neonate at age 2 days. Cardiomegaly has disappeared. Pulmonary parenchymal abnormalities are diminishing, but perihilar, streaky markings persist. 
Radiograph of a neonate at age 4 days. Normal heart size and clear lungs are seen. Preferred examination
Standard chest radiography is the preferred radiologic examination.
Limitations of technique
Initially, it may be difficult to distinguish transient tachypnea from other causes of respiratory distress of the newborn.
Differential diagnosis and other problems to be considered
The differential diagnosis includes Hyaline Membrane Disease, Meconium Aspiration, and
neonatal pneumonia. Other conditions to be considered include respiratory distress syndrome, congenital lymphangiectasia, congenital heart disease, polycythemia, cerebral hyperventilation, and anemia/hypovolemia.
Special concerns
Differentiation from other causes of neonatal respiratory distress may take time. Initial evaluation, monitoring, and basic supportive care must cover all diagnostic contingencies.
Radiography
Findings of transient tachypnea of the newborn (TTN) on chest radiographs may include mild, symmetrical lung overaeration; prominent perihilar interstitial markings; and small pleural effusions (see the first image below).[6, 7, 8, 9, 10] Occasionally, the right side may appear more opacified than the left.
Radiograph of a neonate at age 6 hours. Overaeration and streaky, bilateral, pulmonary interstitial opacities and prominent perihilar interstitial markings are seen along with mild cardiomegaly. Radiograph of a neonate at age 2 days. Cardiomegaly has disappeared. Pulmonary parenchymal abnormalities are diminishing, but perihilar, streaky markings persist. Radiograph of a neonate at age 4 days. Normal heart size and clear lungs are seen. The radiographic appearance at times can mimic the diffuse, granular appearance of hyaline membrane disease but without pulmonary underaeration. Neonates with transient tachypnea are usually at term. Radiographic lung changes also may resemble the coarse, interstitial pattern of other causes of pulmonary edema or the irregular pattern of lung opacification seen in meconium aspiration syndrome.
Degree of confidence
The degree of confidence is rather low. Clinicoradiologic correlation helps confirm the diagnosis. Timing also is a key diagnostic factor.
Ultrasonography
A persistent radiographic finding of cardiomegaly should raise suspicions of congenital heart disease. Evaluation by a pediatric cardiologist and echocardiographic imaging should follow.[11]
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