Transient Tachypnea of the Newborn (TTN): Best article 2025

Definition
Transient Tachypnea of the Newborn (TTN) is a self-limited respiratory condition characterized by delayed clearance of fetal lung fluid, leading to mild respiratory distress in newborns.

Pathophysiology

During fetal life, the lungs are filled with fluid.
At birth, fluid is normally cleared through:
Labor-associated hormonal changes (catecholamine surge).
Compression of the thorax during vaginal delivery.
Postnatal pulmonary lymphatic drainage.
TTN occurs when there is delayed reabsorption of this fluid, resulting in:
Increased lung water → decreased pulmonary compliance.
Interference with gas exchange due to poor alveolar ventilation.

Risk Factors

Maternal Factors:

Cesarean delivery without labor.
Maternal diabetes.
Maternal sedation.

Neonatal Factors:

Preterm or late preterm delivery.
Male sex.
Macrosomia.

Clinical Features

Onset: Shortly after birth.
Signs:
Tachypnea (>60 breaths/min).
Mild retractions.
Nasal flaring.
Grunting.
Hypoxemia (mild desaturation).
Typically resolves within 48-72 hours.

Diagnosis

Investigations to rule out other causes of respiratory distress:

Chest X-ray findings:

Perihilar streaking (interstitial fluid accumulation).
Fluid in fissures.
Hyperinflation.
Mild cardiomegaly (rarely).

Blood gas:

Mild respiratory acidosis (if significant distress).

Differential Diagnosis

Respiratory distress syndrome (RDS).
Neonatal pneumonia.
Persistent pulmonary hypertension of the newborn (PPHN).
Meconium aspiration syndrome (MAS).

Management

Supportive care:
Oxygen therapy (if SpO₂ < 90%).
Continuous Positive Airway Pressure (CPAP) for significant distress.
Thermal regulation and fluid management.
Monitor for resolution within 48-72 hours.

Prognosis

Excellent prognosis: TTN is self-limiting with no long-term sequelae.
Rare progression to other conditions (e.g., pulmonary hypertension).