Neonates who suffer hypoxic stress in utero may pass meconium into the amniotic fluid and then inhale it into the upper airways. Such neonates are usually postmature. This inhalation results in the meconium aspiration syndrome, in which patchy widespread collapse of the lungs and consolidation occur with a severe inflammatory reaction. The meconium may cause complete bronchial obstruction or a partial occlusion with a ball valve effect that may lead to areas of hyperinflation in the distal segments of the lungs [1].
        The symptoms are variable, depending on the severity of aspiration, and may include tachypnea, grunting, retractions, and cyanosis [2]. The diagnosis is confirmed by observation of meconium in the airway below the vocal cords.
        The radiographic findings of meconium aspiration syndrome vary with the severity of aspiration. They may be normal if the meconium is largely tracheal and has been removed [3]. Mild cases may simply manifest overaeration with small streaks or patches. In more severe cases there are overaerated lungs with asymmetric, coarse, patchy infiltrates due to subsegmental atelectasis [4] (Figures 1 and 2). Pneumothorax and pneumomediastinum may result from sudden attempts to clear bronchi of meconium [2] (Figure 1).