Chronic intrauterine meconium aspiration causes fetal lung infarcts, lung rupture, and meconium embolism.
Three neonates with chronic intrauterine meconium aspiration are reported. All had distinctive subpleural plate-infarcts of the lungs caused by meconium-induced vasoconstriction of peripheral preacinar arteries. These vessels showed plexogenic arteriopathy with medionecrosis and obliterative hyaline sclerosis. Organized thrombi and systemic-pulmonary arterial anastomoses were numerous. The infarcts contained inspissated meconium with a granulomatous reaction. In one case, lung rupture occurred, causing meconiumthorax and meconium embolism to hilar lymphatics and lymph nodes; this suggests that particulate meconium may enter the circulation. This fetus had rubella and probable acute twin-twin transfusion following the intrauterine death of the co-twin. The cause of the hypoxia that led to intrauterine passage of meconium in the other cases is unknown. Meconium-stained amniotic fluid was noted in only one case.
Kearney
M S
MS
Department of Pathology, University Hospital of Tromso, Box 27, N-9038 Tromso, Norway.
D002908:Chronic Disease; D004200:Diseases in Twins; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000098:blood supply / Q000473:pathology; D008297:Male; D008471:Meconium Aspiration Syndrome / Q000150:complications* / Q000473:pathology; D011655:Pulmonary Embolism / Q000209:etiology* / Q000473:pathology; D012127:Respiratory Distress Syndrome, Newborn / Q000209:etiology / Q000473:pathology