title: Meconium-related ileus in extremely low-birthweight neonates: etiological considerations from histology and radiology.
abstract: BACKGROUND
  A nationwide survey on neonatal surgery conducted by the Japanese Society of Pediatric Surgeons has demonstrated that the mortality of neonatal intestinal perforation has risen over the past 15 years. The incidence of intestinal perforation in extremely low-birthweight (ELBW) neonates has been increasing as more ELBW neonates survive and as the live-birth rate of ELBW has increased. In contrast to necrotizing enterocolitis (NEC) and focal intestinal perforation (FIP), the pathogenesis of meconium-related ileus, defined as functional bowel obstruction characterized by delayed meconium excretion and microcolon, remains unclarified.
  
  
  METHODS
  The histology of 13 ELBW neonates with intestinal perforation secondary to meconium-related ileus was reviewed, and the radiology of 33 cases of meconium-related ileus diagnosed on contrast enema was reviewed. Specimens obtained from 16 ELBW neonates without gastrointestinal disease served as age-matched controls for histological assessment.
  
  
  RESULTS
  The size of the ganglion cell nucleus in meconium-related ileus and in control subjects was 47.3 ± 22.0 µm(2) and 37.8 ± 11.6 µm(2), respectively, which was not significantly different. In all cases of meconium-related ileus, contrast enema demonstrated a microcolon or small-sized colon, with a gradual caliber change in the ileum and filling defects due to meconium in the ileum or colon, showing not-identical locations of caliber changes and filling defects.
  
  
  CONCLUSIONS
  Morphological immaturity of ganglia was not suggested to be the pathogenesis of meconium-related ileus. Impaction of inspissated meconium is not the cause of obstruction, but the result of excessive water absorption in the hypoperistaltic bowel before birth, although the underlying mechanism responsible for the fetal hypoperistalsis remains unclear.
authors.affiliation: Department of Pediatric Surgery, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan. kubota@mch.pref.osaka.jp
authors.forename: Akio
authors.initials: A
authors.lastname: Kubota
authors.forename: Jun
authors.initials: J
authors.lastname: Shiraishi
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Kawahara
authors.forename: Hiroomi
authors.initials: H
authors.lastname: Okuyama
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoneda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakai
authors.forename: Keigo
authors.initials: K
authors.lastname: Nara
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kitajima
authors.forename: Masanori
authors.initials: M
authors.lastname: Fujimura
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kuwae
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakayama
mesh_terms: D003106:Colon / Q000000981:diagnostic imaging / Q000294:innervation / Q000473:pathology; D003108:Colonic Diseases / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D003287:Contrast Media / Q000008:administration & dosage; D003937:Diagnosis, Differential; D004733:Enema; D005728:Ganglia, Sympathetic / Q000473:pathology*; D005865:Gestational Age; D006801:Humans; D045823:Ileus / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D019102:Infant, Very Low Birth Weight; D007813:Laparotomy; D008470:Meconium; D011379:Prognosis; D011860:Radiography, Abdominal / Q000379:methods*
chemical_list: D003287:Contrast Media