Eur J Pediatr (2011) 170:1495–1505 DOI 10.1007/s00431-011-1453-2 REVIEW Glucocorticoids in the treatment of neonatal meconium aspiration syndrome Daniela Mokra & Juraj Mokry Received: 13 October 2010 / Accepted: 14 March 2011 / Published online: 6 April 2011 # The Author(s) 2011. This article is published with open access at Springerlink.com Abstract Meconium aspiration syndrome is a serious neonatal disease with complex pathophysiology. With respect to the contribution of meconium-induced lung edema, inflammation and vasoconstriction on the course of the disease, glucocorticoids are increasingly used in the treatment of MAS despite the fact that principal questions on the choice of GCs derivative, mode of delivery and dosing have not been answered yet. To bring a complex insight into the topic, this article reviews the pathomechan- isms of MAS, mechanisms of action of GCs, as well as the advantages and disadvantages of GCs administration in experimental models and newborns with MAS. Keywords Meconium aspiration . Glucocorticoids . Inflammation Introduction Meconium aspiration syndrome Meconium aspiration syndrome (MAS) is a major cause of respiratory morbidity and mortality in the term and post- term newborns. The incidence of MAS in the well- developed countries stands at about one to two per 1,000 D. Mokra (*) Department of Physiology, Jessenius Faculty of Medicine, Comenius University, Mala Hora 4, SK-03601, Martin, Slovakia e-mail: mokra@jfmed.uniba.sk J. Mokry Department of Pharmacology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia live births; however, in the developing countries, this number may be considerably higher [19]. The clinical picture varies from mild tachypnoea to life-threatening respiratory failure associated with pulmonary hypertension [16]. In addition to acute effects, MAS may also have serious long-term consequences on the respiratory system, whereas abnormal bronchial reactivity, wheezing and other respiratory pathology were found in a considerable portion of infants who overcome MAS in the neonatal period [80]. Despite an improved understanding of the pathomechan- isms of MAS and widening the available therapeutic approach, MAS is often difficult to treat. Therefore, a number of various adjunctive or alternative approaches have been tested in MAS. Since some of them have been rather well established (e.g. different modes of ventilatory support, surfactant treatment and inhaled nitric oxide), the therapeutic potential of others (particularly of anti-inflammatory drugs and vasodilators) is still under research [48]. Pathogenesis of MAS as a rationale for the treatment by glucocorticoids The pathogenesis of MAS is complex, with multiple interactions between the individual pathomechanisms [48]. In an acute phase of the disease, aspirated meconium obstructs the airways. Complete airway obstruction may result in alveolar atelectasis behind the plug. Partial airway obstruction may cause a ball valve effect, and air trapping and air leak into the interstitium may occur [16]. With the initiation of ventilation, aspirated meconium reaches the alveoli, where it inactivates the surfactant [56] and triggers inflammation [86]. Meconium changes the viscosity and ultrastructure of the surfactant [2], decreases the levels of surfactant proteins [15] and accelerates the conversion from large, surface active aggregates into small, less active