Meconium peritonitis

Plain film shows numerous dilated loops of bowel occupying the entire abdominal cavity, including the pelvic portion, and multiple air-fluid levels in upright film (Fig. 1.19). With this degree of distension the mucosal pattern of the small bowel is effaced and it is impossible to differentiate the small bowel from the colon (Winters et al. 1992). Examination of the colon is then warranted to disclose the presence or absence of a colonic lesion. In ileal atresia, the colon is normally placed but has an abnormally small caliber, the so-called functional microcolon typical of distal small bowel obstruction (Dalla Vecchia et al. 1998) (Fig. 1.19d,e). The presence of pneumoperitoneum indicates that perforation has occurred and a colon examination is contraindicated. Intraperitoneal calcifications, indicative of meconium peritonitis, are not uncommon in ileal atresia. 

Meconium peritonitis is a condition that is the result of in utero perforation of the fetal gastrointestinal tract during the last 6 months of pregnancy. Sterile meconium escapes through the perforation into the peritoneal cavity producing a marked reaction with dense adhesions, which usually calcify rap-... 

Fig. 1.24a,b. Meconium peritonitis, a Abdominal radiograph demonstrates a small amount of gas in a markedly distended abdomen. A calcified mass within the peritoneal cavity is observed (arrows). There is no pneumoperitoneum, b Sonography of the same patient shows a pseudocyst containing debris with peripheral calcification... 

Ultrasound maybe useful in these patients, especially in the presence of a relatively airless abdomen. Meconium peritonitis predominantly presents two ultrasound appearances general or cystic abnormality. With the generalized condition, highly echogenic material spreads throughout the abdomen and around the bowel loops (Fig. 1.27), producing a... 

Fig. 1.26. Meconium peritonitis with intrauterine bowel perforation. Free air within the peritoneal cavity is observed (arrows) in this neonate with ileal atresia. No bowel distension is observed. A patent bowel perforation was found at surgery...

Meconium peritonitis may also be diagnosed by prenatal ultrasound. It can present as fetal meconium ascites, giant pseudocysts, small pseudocysts, and calcifications. Associated polyhydramnios is a common finding (Eckoldt et al. 2003 Kamata et al. 2000). 

Fig. 1. 27a-c. Meconium peritonitis in a neonate with cystic fibrosis. Sonography demonstrates intraabdominal calcifications over the liver surface (a), around the spleen (b), and around the bowel loops (c) (arrows). Note the hyperechogenic inspissated meconium into the bowel loops... 

Contrast-enema usually reveals a microcolon distal to the atresia, with obstruction to the retrograde flow of barium at the site of the atresia (Fig. 1.29). A wind-sock appearance may be observed with membranous atresias (Winters et al. 1992). Calcification of meconium peritonitis due to in utero bowel perforation is present in about 12% of atresia cases, and can be diagnosed antenatally by sonography. 

Kamata S, Nose K, Ishikawa S, Usui N, Sawai T, Kitayama Y, Okuyama H, Imura K et al (2000) Meconium peritonitis in utero., Pediatr Surg Int 16 377-379 Kao SC, Franken EA Jr (1995) Nonoperative treatment of simple meconium ileus a survey of the Society for Pediatric Radiology. Pediatr Radiol 25 97-100 Karmazyn B, Werner EA, Rejaie B et al (2005) Mesenteric lymph nodes in children what is normal Pediatr Radiol 35 774-777... 

Lawrence PW, Chrispin A (1984) Sonographic appearances in two neonates with generalized meconium peritonitis the snowstorm sign. Br J Radiol 57 340-342... 

Reynolds E, Douglass B, Bleacher) (2000) Meconium peritonitis. J Perinatol 20 193-195... 

Salman AB, Karaoglanoglu N, Suma S (1999) Abdominal, scrotal, and thoracic calcifications owing to healed meconium peritonitis. J Pediatr Surg 34 1415-1416 Sargent MA, Babyn P, Alton DJ (1994) Plain abdominal radiography in suspected intussusception a reassessment. Pediatr Radiol 24 17-20... 

Duodenal Obstruction 170 Jejunal and Ileal Obstruction 172 Meconium Peritonitis 173 Meconium Ileus 173 Megacystis-Microcolon-Malrotation-Intestinal-Hypoperistalsis Syndrome (MMMIHS) 174... 

Some of the pathologies of the small intestine are discussed in Chapter 1. In the current chapter, therefore, little or no attention will be paid to (midgut volvulus) malrotation, the atresias, meconium ileus, meconium peritonitis, duplication cysts, necrotizing enterocolitis (NEC) and intussusception. 

The radiological diagnosis of obstruction is usually visible on the conventional (plain) radiograph. In uncomplicated cases these radiographs of the abdomen are sufficient. The pre-atretic intestinal loops are dilated because of accumulation of large amounts of fluid and fluid levels are usually present on horizontal beam films. In case of jejunal atresia only a few loops of distended jejunum are present in the left upper abdomen, while in ileal atresia many dilated loops are identified. In complicated cases, especially with an abnormally distended and painful abdomen, a colon enema or US can be useful- particularly from the differential diagnostic point of view to exclude meconium ileus or meconium peritonitis. In case of atresia, a microcolon without the presence of meconium is usually found (Devos and Meradji 2003). 

Fig. 5.8. a A neonate with a distended, practically gasless abdomen characteristic for meconium peritonitis. The streaky and flocculent calcifications in the peritoneal cavity are specific, b A neonate with meconium peritonitis and a rounded cystic calcification located intraperitoneally. Distended abdomen with reduced intestinal air... 

Fig. 5.9. Ileal duplication cyst in an infant with meconium peritonitis. Note the additional punctate calcifications and echogenic meconium intraperitoneally (arrows)...

Complications of meconium ileus are volvulus, perforation, small bowel atresia and meconium peritonitis with abdominal calcifications. 

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