intestinal perforation

this shows a dense mass of what appears to be bowel contents in the right side of the abdominal cavity. the mass has an irregular lining with possible concretions and is in keeping with the meconium peritonitis. a fine adhesion is seen in some views crossing the mass.

this clip shows two cases; the first with clearly dilated bowel and large discrete area of calcification, the second shows a more normal bowel outline with an area of calcification which moves with the bowel. in both cases, these changes will have arisen from prior bowel perforation.

description

perforation usually occurs as the result of bowel obstruction which may arise as the result of a vascular accident to the bowel such as volvulus, intussusception, or secondary to severe growth retardation. obstructive problems may also arise from meconium ileus as seen in cystic fibrosis or later in pregnancy, hirschsprung’s disease, although intrauterine perforation in the latter condition is not reported.

diagnosis

the ascites develops as a result of the peritoneal irritation arising from leaked meconium. there are probably two phases – the first, an acute one in which generalised ascites forms and the second, an adhesive one when the ascites begins to be walled-off leading to the development of pseudoascites. under these circumstances the gut often appears bound to the posterior abdominal wall rather than floating. calcified deposits appear on the peritoneal surfaces. further obstructive changes may appear but spontaneous resolution is also observed.

differential diagnosis

ascites should always raise the possibility of the development of both immune and non-immune hydrops. the standard investigations for non-immune hydrops include infection screens, exclusion of aneuploidy and a careful search for additional structural problems in the fetus.

sonographic features

solid mass of apparent bowel contents which may appear walled-off

ascites or pseudoascites

thickening of the peritoneum with calcified concretions

often evidence of a gut obstruction

associated syndromes

anorectal atresia
congenital infections
cystic fibrosis
hirschsprung disease
meconium peritonitis
multiple intestinal atresias

references

dunne m, haney p, sun cc sonographic features of bowel perforation and calcific meconium peritonitis in utero pediatr radiol 13; 231-233
shalev j, frankel y, avigad i, mashiach s spontaneous intestinal perforation in utero; ultrasonic diagnostic criteria am j obstet gynecol 144; 855-857