Respiratory Distress In the Newborn

Feature	TTN (Transient Tachypnea of the Newborn)	HMD / RDS (Hyaline Membrane Disease)	MAS (Meconium Aspiration Syndrome)	BPD (Bronchopulmonary Dysplasia)
Typical gestation	Term / late preterm	Preterm	Term / post-term	Very preterm
Time of onset	Within hours of birth	At birth → worsens in 24–48 h	At birth	After weeks (chronic)
Primary mechanism	Delayed lung fluid clearance	Surfactant deficiency → atelectasis	Airway obstruction + pneumonitis + surfactant inactivation	Arrested alveolar & vascular development
Risk factors	C-section (no labor), IDM	Prematurity, IDM	Fetal distress, post-term	Prolonged ventilation, high FiO₂
Severity	Mild–moderate	Moderate–severe	Moderate–severe	Chronic respiratory disease
Oxygen need	Low–moderate, short duration	High, increasing early	Often high	Persistent, long-term
Response to O₂	Good	Partial	Variable/poor	Variable
Chest X-ray	Prominent vascular markings, fluid in fissures	Ground-glass, air bronchograms	Patchy infiltrates, hyperinflation	Hyperinflation, cystic changes
Course	Self-limited (24–72 h)	Improves with treatment	Variable, may complicate	Prolonged (weeks–months)
Main treatment	Supportive, CPAP	CPAP + surfactant	Ventilation, supportive	Prevention + supportive