60 Microcolon/Meconium Ileus

CASE 60


Clinical Presentation


Term neonate presents with a distended abdomen and failure to pass meconium after 48 hours.


image

Figure 60A


Radiologic Findings


Non-ionic contrast enema (Fig. 60A1) in a 2-day-old girl demonstrates a microcolon. Reflux of contrast has occurred into mildly dilated loops of distal ileum, containing meconium plugs, but does not reach the more proximal dilated air-filled loops. Further reflux was achieved during a repeat examination the following day (Fig. 60A2), with opacification of significantly more dilated loops in the mid-ileum, containing further inspissated meconium.


Diagnosis


Meconium ileus


Differential Diagnosis



  • Low gastrointestinal (GI) obstruction on abdominal radiograph-wide differential

    • Ileal atresia
    • Hirschsprung’s disease
    • Functional immaturity/left colon syndrome
    • Anorectal anomaly
    • Colonic atresia
    • Sepsis/electrolyte disturbance
    • Megacystis-microcolon-hypoperistalsis syndrome (rare)

  • Microcolon on enema

    • Ileal atresia—microcolon with reflux of contrast into nondilated distal ileum. If contrast reaches the atretic segment, an abrupt convex termination is seen, with residual unopacified dilated proximal small bowel loops.
    • Megacystis-microcolon-hypoperistalsis syndrome (rare)—transient neonatal microcolon in association with a large-volume bladder and a variable degree of upper renal tract dilatation. Malrotation is common.
    • Total colonic Hirschsprung’s disease (may present as a small-caliber colon, although not usually as small as a “microcolon”)

Discussion


Background


Meconium ileus is a neonatal obstruction of the ileum by abnormally viscid, inspissated pellets of meconium.


Etiology



  • Almost all cases are associated with an underlying diagnosis of cystic fibrosis (CF). Conversely, meconium ileus is the initial presentation of 10 to 15% of CF cases.
  • Rare cases have been described in association with partial pancreatic aplasia or stenosis of the pancreatic ducts.

Clinical Findings


Low GI obstruction—abdominal distension, failure to pass meconium, and sometimes vomiting — within the first 48 hours of life


Associated Conditions



Complications



 


image

Figure 60B Supine (1) and cross-table lateral (2) abdominal x-ray of a 2-day-old girl showing generalized bowel dilatation with a mottled appearance of air mixed with meconium, in this case more prominent in the left flank. Enema confirmed meconium ileus with an underlying diagnosis of CF.


Pathology

Dec 21, 2015 | Posted by in PEDIATRIC IMAGING | Comments Off on 60 Microcolon/Meconium Ileus
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