Meconium peritonitis presenting as fetal ascites on ultrasound

Abstract

Meconium peritonitis is a sterile chemical peritonitis resulting from the extrusion of meconium from the fetal gut into the peritoneal cavity. The cause of this sequence of events is bowel perforation proximal to an obstruction which may be caused by meconium ileus, volvulus, hernia or atresia resulting from ischaemia (Tucker and Izant, 1971). The irritant meconium causes peritonitis which frequently localizes, resulting in the formation of sterile abscesses. With healing, calcification takes place, forming scattered plaques on the peritoneal surface. The perforation may result in a large communicating cyst (giant meconium peritonitis), in which case calcification takes the form of a circular plaque (Kolawole et al., 1973). A 25-year-old coloured female, Para 3, Gravida 4, was admitted to hospital at 30 weeks gestation, with an antepartum haemorrhage and mild toxaemia. She was referred to the ultrasound department for an estimation of the gestational period (biparietal diameter measurement) and placental localization. A placenta praevia was demonstrated (Fig. 1). The amount of liquor was thought to be within normal limits. The gestation age was assessed as 30 weeks. Fluid was seen within the fetal abdomen surrounding the liver and displacing the bowel centrally (Figs. 2 and 3). The fetal liver echo pattern was normal and there was no sign of bile duct dilation.