Meconium Aspiration syndrome.

Most common cause of neonatal respiratory distress in full term or post mature infants (hyaline membrane disease is most common in premature infants)

Etiology- placental insufficiency/ post maturity result in perinatal hypoxia and fetal distress with meconium defecated in utero.

Pathogenesis- severe hypoxia induces gasping reflex with inhalation of tenacious meconium that produces medium and small airway obstruction with chemical Pneumonitis.

Incidence: 10 % of all deliveries have meconium stained aspiration.

Clinical presentation-

-        cyanosis (rare)

-        Persistent fetal circulatory syndrome i.e. neonatal pulmonary hypertension (secondary to thick walled pulmonary arterioles) and R-L shunt through PDA & foramen ovale with severe cyanosis.

-        Large infant

 Radiological features-

-        bilateral diffuse grossly patchy opacities (Ateletasis and consolidation)

-        hyperinflation with areas of emphysema (air trapping)

-        Spontaneous pneumothorax and pneumomediastinum ( 25- 40%)

-        Mild pleural effusion (10-20)

-        No air bronchograms

Rapid clearing usually within 48 hrs