MECONIUM PERITONITIS

The diagnosis of meconium peritonitis is usually made after 20 weeks gestational age as bowel peristalsis, which is essential to extrude meconium into the peritoneal cavity, rarely commences prior to 20 weeks gestation (1).

• Peritoneal calcifications.
  • Punctate calcifications around the periphery of the expected area of the liver and not in the liver substance itself.
  • Calcifications along the course of the hemidiaphragm.
  • Calcifications in the scrotum of the male fetus (the processus vaginalis connects the scrotal sac to the peritoneal cavity in late pregnancy) (2).

 

• Hyperechogenic mass with acoustic shadowing.

 

• Dilated hyperperistaltic bowel loops.
• Enlarged fetal abdominal circumference.
• ± Polyhydramnios.
• ± Ascites.

 

• Bilateral hydroceles or swollen vulvae if the processus vaginalis is present.
• Most frequent site of perforation.
  • Ileum.
• Meconium peritonitis without intestinal obstruction is probably secondary to and ischemic bowel event. "Idiopathic vascular impairment" has been suggested as the cause (3).

• Fibroadhesive type.
  • Intense fibrotic reaction.
  • May be difficult to image unless it produces bowel obstruction by adhesive bands.

 

• Generalized Type.
  • Peritoneal calcifications.
  • Polyhydramnios (50%).
  • Fetal Ascites (70%).
  • Differential Diagnosis.

 

• Ruptured hydrometrocolpos.
• Intrahepatic and venous calcification.
• TORCH infection.
• Calcified meconium plaques in an obstructed bowel loop.
• Meconium Pseudocyst.
  • Adhesions between bowel loops and omentum which wall off the meconium collection.
  • May be extremely large occupying most of the fetal abdomen.
  • Irregular thick-walled cystic mass ± septations, calcifications or debris.
  • High mortality.
  • Differential Diagnosis.

 

• Ovarian cyst.
• Choledochal cyst.
• Mesenteric cyst.
• GI duplication cyst.
• Hydrometrocolpos.
• Urachal cyst.