Meconium aspiration syndrome

Meconium aspiration syndrome
Other namesNeonatal aspiration of meconium
X-ray showing the extent of lung epithelial damage in response to meconium seen in neonates with meconium aspiration syndrome.
SpecialtyNeonatology

Meconium aspiration syndrome (MAS) also known as neonatal aspiration of meconium is a medical condition affecting newborn infants. It describes the spectrum of disorders and pathophysiology of newborns born in meconium-stained amniotic fluid (MSAF) and have meconium within their lungs. Therefore, MAS has a wide range of severity depending on what conditions and complications develop after parturition. Furthermore, the pathophysiology of MAS is multifactorial and extremely complex which is why it is the leading cause of morbidity and mortality in term infants.[1][2]

The word meconium is derived from the Greek word mēkōnion meaning juice from the opium poppy as the sedative effects it had on the foetus were observed by Aristotle.[3]

Meconium is a sticky dark-green substance which contains gastrointestinal secretions, amniotic fluid, bile acids, bile, blood, mucus, cholesterol, pancreatic secretions, lanugo, vernix caseosa and cellular debris.[1] Meconium accumulates in the foetal gastrointestinal tract throughout the third trimester of pregnancy and it is the first intestinal discharge released within the first 48 hours after birth.[4] Notably, since meconium and the whole content of the gastrointestinal tract is located 'extracorporeally,' its constituents are hidden and normally not recognised by the foetal immune system.[5]

For the meconium within the amniotic fluid to successfully cause MAS, it has to enter the respiratory system during the period when the fluid-filled lungs transition into an air-filled organ capable of gas exchange.[1]

  1. ^ a b c Van Ierland, Y; De Beaufort, AJ (2009). "Why Does Meconium Cause Meconium Aspiration Syndrome? Current Concepts of MAS Pathophysiology". Early Human Development. 85 (10): 617–620. doi:10.1016/j.earlhumdev.2009.09.009. PMID 19833459.
  2. ^ Vain, NE; Batton, DG (2017). "Meconium "Aspiration" (or Respiratory Distress Associated with Meconium-Stained Amniotic Fluid?)". Seminars in Foetal and Neonatal Medicine. 22 (4): 214–219. doi:10.1016/j.siny.2017.04.002. PMID 28411000.
  3. ^ Rahman, S; Unsworth, J; Vause, S (2013). "Meconium in Labour". Obstetrics, Gynaecology and Reproductive Medicine. 23 (8): 247–252. doi:10.1016/j.ogrm.2013.05.007.
  4. ^ Argyridis, S; Arulkumaran, S (2016). "Meconium Stained Amniotic Fluid". Obstetrics, Gynaecology and Reproductive Medicine. 26 (8): 227–230. doi:10.1016/j.ogrm.2016.05.001.
  5. ^ Lindenskov, PHH; Castellheim, A; Saugstad, OD (2015). "Meconium Aspiration Syndrome: Possible Pathophysiological Mechanisms and Future Potential Therapies". Neonatology. 107 (3): 225–230. doi:10.1159/000369373. PMID 25721501.