Bowel Obstruction Associated With Fetal Echogenic Distended Bowel Loop
A Boy With Abdominal Distention and Bilious Vomiting
Echogenic bowel has been defined as bowel of similar or greater echogenicity on ultrasonography than surrounding tissues, such as liver, bones, and lung.1-3 Bowel obstruction is an unusual outcome of echogenic distended bowel loop. Here we report a case of newborn boy with prenatal ultrasonography results showing echogenic distended bowel loop due to bowel obstruction.
A full-term boy, appropriate for gestational age, was born by normal spontaneous vaginal delivery and had Apgar scores of 9 at 1 minute and 9 at 5 minutes. The child’s birth weight was 3625 g. His mother was 16 years of age, and she had undergone the following maternal prenatal tests: human immunodeficiency virus test, syphilis immunoglobulin G, hepatitis B surface antigen, gonorrhea and chlamydia, group B streptococcus, tuberculosis, and urine culture to screen for asymptomatic bacteriuria. The test results all were negative. In addition, the results of a rubella blood test indicated that she was reactive immune, and triple screen and glucose tolerance test results were both within reference ranges.
However, the pregnancy had been complicated by prenatal ultrasonography findings at 23 weeks that had revealed prominent loops of the right colon (Figure 1). Sequential ultrasonography results showed persistent dilatation of loops of bowel, with normal amniotic fluids and no other fetal anomalies. After birth, the neonate did not pass meconium in the first 48 hours, and he exhibited abdominal distention and bilious vomiting.
Serial abdominal radiography results showed progressive dilation of bowel loops, with findings suggestive of pneumoperitoneum (Figure 2). The patient was transferred to a tertiary facility where partial colon resection was done and intraoperative findings were significant for complete atresia of the colonic hepatic flexure and massive dilatation of the ascending colon.
Prenatal ultrasonography remains an important tool in the evaluation of fetal anatomy, although subjective assessments of echogenic bowel are prone to significant interobserver variation.2-4 Echogenic bowel is a sonographic finding of unknown cause and has potentially significant prenatal and postnatal complications.5,6 It has been associated with congenital infections, cystic fibrosis, chromosomal abnormalities, and bowel obstruction.1 The incidence of echogenic bowel has been reported as 0.2% in a series of 30 cases and in 4% of routine second-trimester ultrasonography examinations.4,6
In a case series of 21 fetuses, diagnosis of isolated echogenic bowel was reported between 14 to 21 weeks of gestation. In 90% of the cases, the results of follow-up ultrasonography revealed that the echogenic bowel had resolved, and the patients had unremarkable postnatal outcomes. Only 9% of patients had postnatal complications.7 Thus, echogenic bowel is usually a transient finding without any postnatal complications. Intestinal atresia is a very rare complication of this finding.
In our case, an evaluation by an experienced radiologist indicated that echogenic bowel was visualized throughout the abdomen prenatally. In addition, the dilatation of the bowel was persistent and remarkable in subsequent ultrasonography results. Despite the rareness of complications, the literature and our case results both suggest that it is important to pay attention to echogenicity in prenatal ultrasonography in order to follow up clinically and promptly diagnose any medical conditions.
Neonatal intestinal obstruction is rarely caused by atresia of the colon (1 in 20,000 live births),8 and atresia of the hepatic flexure is the least frequent type.9 However, when neonatal intestinal obstruction due to colonic atresia does occur, mortality is high when surgical management is delayed for more than 72 hours, though the prognosis is usually satisfactory with early diagnosis and proper management.10 In the case of our patient, the colonic atresia was identified at 48 hours, and successful surgical management occurred before 72 hours of life. Our findings confirm the importance of early identification and early management of these patients.
Echogenic bowel is a rare finding that can be associated with significant medical conditions that require frequent prenatal examination and close postnatal monitoring. Ultrasonography findings are subjective, but persistent echogenic bowel in prenatal ultrasonography should alert the clinician to possible causes of bowel obstruction such as atresia of the colon. With advancements in surgical techniques, early identification of atresia of the colon has a promising outcome.
Sandra Camacho, MD; Amir Navaei, MD; Anshu Kumari, MD; and Magda Mendez, MD, are from the department of pediatrics at Lincoln Medical Center in Bronx, New York, which is affiliated with Weill Cornell Medical College.
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