A pattern-based approach to bowel obstruction in the newborn

Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome: A Case Report of an Uncommon Condition

The megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS), also known as Berdon syndrome, is a rare congenital condition that falls within the spectrum of visceral myopathies. It is characterized by the presence of megacystis, microcolon, and hypoperistalsis, which are secondary to gastrointestinal and urinary system dysmotility. It is frequently associated with other alterations in the gastrointestinal and genitourinary tracts. Although it is possible to make the diagnosis in the prenatal period, most cases are diagnosed after birth through genetic and imaging studies. Advances in treatment have led to a progressive increase in survival rates. We present the case of a newborn with congenital alterations described prenatally and with imaging findings characteristic of the syndrome.

[Malrotation and Midgut Volvulus in Children: Diagnostic Approach, Imaging Findings, and Pitfalls]

Malrotation and midgut volvulus are surgical emergencies that commonly occur within the first month of life. The classic symptom is acute bilious vomiting, while nonspecific symptoms such as recurrent abdominal pain may be present in older children. Malrotation can be associated with duodenal obstruction caused by an abnormal peritoneal fibrous band or congenital anomalies, such as an annular pancreas or a preduodenal portal vein. Volvulus can lead to bowel ischemia and a life-threatening condition, thus prompt and accurate diagnosis is crucial. Diagnosis can be made through upper gastrointestinal series, ultrasonography, and CT, with ultrasonography being preferred as a screening tool due to its rapid and accurate diagnosis, without radiation exposure, in children. This pictorial essay discusses the key imaging findings and diagnostic approaches for malrotation and midgut volvulus, as well as diagnostic pitfalls based on actual cases.

Imaging Features of Neonatal Bowel Obstruction

Radiologic evaluation of neonatal bowel obstruction is challenging owing to the overlapping clinical features and imaging appearances of the most common differential diagnoses. The key to providing an appropriate differential diagnosis comes from a combination of the patient's gestational age, clinical features, and imaging findings. While assessment of radiographs can confirm bowel obstruction and indicate whether it is likely proximal or distal, additional findings at upper or lower gastrointestinal contrast study together with use of US are important in providing an appropriate differential diagnosis. The authors provide an in-depth assessment of the appearances of the most common differential diagnoses of proximal and distal neonatal bowel obstruction at abdominal radiography and upper and lower gastrointestinal contrast studies. These are divided into imaging patterns and their associated differential diagnoses on the basis of abdominal radiographic findings. These findings include esophageal atresia variants including the "single bubble," "double bubble," and "triple bubble" and distal bowel obstruction involving the small and large bowel. Entities discussed include esophageal atresia, hypertrophic pyloric stenosis, pyloric atresia, duodenal atresia, duodenal web, malrotation with midgut volvulus, jejunal atresia, ileal atresia, meconium ileus, segmental volvulus, internal hernia, colonic atresia, Hirschsprung disease, and functional immaturity of the large bowel. The authors include the advantages of abdominal US in this algorithm, particularly for hypertrophic pyloric stenosis, duodenal web, malrotation with midgut volvulus, and segmental volvulus. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

US for Evaluation of Acute Abdominal Conditions in Neonates

US is the imaging modality of choice for evaluation of a variety of abdominal conditions, and in recent years it has also become useful and promising as a bedside technique for assessment of acute abdominal conditions in neonates. Bedside US can help, complement, and sometimes replace radiographic or contrast-enhanced studies in critically ill and labile neonates who are difficult to transport to the fluoroscopy suite. Some of the features of bedside US can be applied as point-of-care US (POCUS) of the sick neonate. Some of the abdominal conditions in neonates that can be assessed and monitored with bedside US are necrotizing enterocolitis and its complications, malrotation with a midgut volvulus, segmental volvulus, meconium peritonitis, and complicated inguinal hernia. High-resolution US with the use of 15-MHz and higher-frequency probes allows characterization of the bowel anatomy and features of intestinal abnormalities in neonates in fine detail. Color Doppler US and microvascular imaging improve accuracy in the detection and characterization of bowel vascularity, which is important in the treatment and follow-up of patients with intestinal conditions. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. The slide presentation from the RSNA Annual Meeting is available for this article.

Neonatal Gastrointestinal Emergencies: A Radiological Review

BACKGROUND

Abdominal emergencies in neonates require surgical management in almost all cases and complications may include bowel perforation, sepsis, shock, and even death. Radiological imaging has become a very important aid in the clinical setting as it shortens time to diagnosis.

OBJECTIVE

The objective of this review is to discuss the more prevalent neonatal gastrointestinal emergencies, review appropriate imaging options, and illustrate common radiological presentations of these entities.

CONCLUSION

Despite advancements in imaging techniques, it is important to keep in mind that neonates have a higher susceptibility to the adverse effects of ionizing radiation, and therefore radiography and ultrasonography remain the main diagnostic modalities for ruling out the diseases with the worst prognosis. Other modalities (fluoroscopy, computed tomography, and magnetic resonance imaging) may have limited use in very specific conditions. All providers in an emergency department should be familiar with the basic radiological findings that may indicate a gastrointestinal emergency, especially in health institutions that do not have 24-h radiologist coverage.

Congenital Colonic Stenosis: A Rare Gastrointestinal Malformation in Children

Aims

Congenital colonic stenosis (CCS) is an extremely rare cause of low-intestinal obstruction in neonates/child. We report our experience with seven cases of CCS presenting with low-intestinal obstruction and diagnosed intraoperatively and also propose an algorithm for its appropriate treatment for the adequate outcome.

Materials and Methods

It was a retrospective study of seven patients of CCS including two neonates (5-days and 15-days old), four infants (age range - 2-11 months), and one 24-month-old child admitted from 2014 to 2019. Information regarding the age of presentation, clinical presentation, physical findings, radiological and laboratory findings, details of surgery, and outcome was retrieved and analyzed.

Results

The male-to-female ratio was 5:2. Patients were initially diagnosed as cases of Hirschsprung's disease in five and ileal atresia in two. A final diagnosis of CCS was made during surgery and histopathological examination of resected stenotic segment. The segment involved was ascending colon in three, transverse colon in two, and sigmoid colon and junction of descending and sigmoid colon each in one patient. Resection of stenotic colonic segment and primary end-to-end anastomosis was performed in two, divided stoma after resection of the stenotic segment and secondary anastomosis in three, and proximal loop terminal ileostomy followed by resection of the stenotic colonic segment and ileocolic anastomosis after 10-12 weeks in two.

Conclusions

CCS is a rare but possible cause of large-bowel obstruction, in neonatal, infant, and children particularly when associated with a history of chronic constipation since birth. It should be kept in mind as a differential diagnosis while managing a case of neonatal and pediatric intestinal obstruction, particularly low-bowel obstruction along with a history of chronic constipation. Treatment should be individualized for each patient based on clinical status and associated anomalies to give the best results with less morbidity.

Small-bowel atresias: a case series with review of the disease and imaging findings

Small-bowel atresias are among the most common causes of intestinal obstruction in newborns, and they often require urgent surgical treatment. Imaging techniques play a very important role in their diagnosis, which is often suspected on prenatal obstetric ultrasound and confirmed on postnatal plain-film X-rays. Abdominal ultrasound's lack of ionizing radiation, wide availability, low cost, and high resolution is making this technique increasingly important in confirming atresias and in detecting possible complications in newborns. This review analyzes a series of cases seen at our center. It summarizes the different types of small-bowel atresias, focusing on the clinical presentation, imaging findings on different modalities, presence of associated disease, management, clinical course, and outcomes.

Diagnostic decision-making tool for imaging term neonatal bowel obstruction

Term neonatal bowel obstruction is common, and absence of treatment is potentially catastrophic. There is a relatively narrow differential diagnosis, with causes categorised as either low or high bowel obstruction. The commonest causes of low bowel obstruction include anorectal malformations (ARM), Hirschsprung's disease, ileal atresia, meconium ileus, meconium plug, and colonic atresia. The commonest causes of high bowel obstruction include duodenal atresia, duodenal stenosis/web, jejunal atresia, and malrotation with volvulus (and hypertrophic pyloric stenosis usually presenting in slightly older infants). Diagnosis can be decided using a step-wise binary decision tool that includes the appropriate imaging steps and evaluation of bowel calibre. This paper presents the decision-making tool from the presenting features, through plain radiographic findings and, where necessary, the additional radiological investigations to assist the general radiologist, novice paediatric radiologist and paediatric surgeon. The tool is pictorial, with the radiological findings accompanied by eight schematics, serving as a simplified visual aid for memorizing the imaging patterns of the differential diagnosis. The imaging and decision-making steps allow for a rapid, simplified diagnosis that can benefit patients by recommending when to perform surgery, when to perform further imaging, and when imaging can act in a therapeutic manner.

Duodenal Stenosis: A Diagnostic Challenge in a Neonate With Poor Weight Gain

Cases of isolated duodenal stenosis in the neonatal period are minimally reported in pediatric literature. Causes of small bowel obstruction such as duodenal atresia or malrotation with midgut volvulus have been well documented and are often diagnosed due to their acute clinical presentation. Duodenal stenosis, however, causes an incomplete intestinal obstruction with a more indolent and varying clinical presentation thus making it a diagnostic challenge. We present a neonate with a unique case of congenital duodenal stenosis. The neonate presented with poor weight gain and frequent "spit-ups" as per the mother at the initial newborn visit. The clinical presentation was masked as the patient was being fed infrequently and with concentrated formula. We postulate that this may be due to the fact that the mother was an adolescent and relatively inexperienced with newborn care. During the hospital course, the patient had recurrent episodes of emesis with notable electrolyte abnormalities including hypochloremia and metabolic alkalosis. Further investigation with an abdominal X-ray showed dilated loops of bowel. Pyloric stenosis was ruled out via abdominal ultrasound. An upper gastrointestinal (GI) series ultimately confirmed a diagnosis of duodenal stenosis and the infant underwent surgical repair with full recovery. Congenital duodenal stenosis may have atypical presentations in neonates requiring pediatricians to have a high index of suspicion for diagnosis and to ensure timely therapy.

The role of sonography in differentiating congenital intrinsic duodenal anomalies from midgut malrotation: emphasizing the new signs of duodenal and gastric wall thickening and hyperechogenicity

BACKGROUND

The clinical and plain radiographic differentiation of congenital intrinsic duodenal anomalies (atresia, web, stenosis) from intestinal malrotation is not always clear. Although sonography has been documented as an important diagnostic tool in the differentiation of these two entities, its role is still not widely appreciated and it is still not universally utilized in this clinical setting.

OBJECTIVE

To assess the usefulness of sonographic features of the duodenal and gastric wall in the differentiation of congenital intrinsic duodenal anomalies from midgut malrotation in a large series of neonates and to compare them with other features on abdominal radiographs, ultrasound and upper gastrointestinal series.

MATERIALS AND METHODS

Using the surgical database at our tertiary pediatric hospital, we identified neonates who had surgically proven congenital intrinsic duodenal anomalies or malrotation over a period of 15 years (2000-2015). We reviewed imaging findings in both groups of neonates (blinded to the final diagnosis) with attention to the echogenicity and thickness of the wall of the duodenum and stomach, the relationship between the superior mesenteric artery and vein, the position of the third portion of the duodenum and the presence of the whirlpool sign. Findings were compared between the groups using the unpaired t-test and Fisher exact test.

RESULTS

We included 107 neonates in the study, 40 with a congenital intrinsic duodenal anomaly, 49 with malrotation (36 with volvulus) and 18 with a combination of both. Duodenal and gastric wall thickening and hyperechogenicity were significantly more common in the group with a congenital intrinsic duodenal anomaly compared to those with malrotation (P<0.0001). Conversely, an abnormal relationship between the superior mesenteric artery and vein, abnormal position of the third part of the duodenum, and the whirlpool sign were significantly more common in neonates with malrotation than in those with congenital intrinsic duodenal anomalies (P<0.0001).

CONCLUSION

Duodenal or gastric wall thickening, and increased wall echogenicity are helpful sonographic features in the differentiation of congenital intrinsic duodenal anomalies from malrotation. Evaluation of the duodenal and gastric wall should thus be added to the features routinely assessed on ultrasound examinations in the clinical setting of suspected duodenal obstruction in the neonate.

Neonatal Bowel Disorders: Practical Imaging Algorithm for Trainees and General Radiologists

OBJECTIVE

Neonatal bowel disorders require prompt and accurate diagnosis to avoid potential morbidity and mortality. Symptoms such as feeding intolerance, emesis, or failure to pass meconium may prompt a radiologic evaluation.

CONCLUSION

We discuss the most common neonatal bowel disorders and present a practical imaging algorithm for trainees and general radiologists.

Evaluation of a pediatric fluoroscopy training module to improve performance of upper gastrointestinal procedures in neonates with bilious emesis

BACKGROUND

Life-threatening midgut volvulus usually occurs in infants with malrotation and requires rapid diagnosis and surgical treatment to prevent bowel necrosis and death. However, because of the low frequency of upper gastrointestinal studies performed in infants younger than 1 month, many diagnostic radiology residents finish their residency training having limited or no opportunity to perform or observe an upper gastrointestinal (GI) series for evaluation of bilious emesis in a neonate.

OBJECTIVE

To determine whether adding simulated upper GI series on neonates with bilious emesis to the curriculum improves residents' skill and accuracy in diagnosing midgut volvulus.

MATERIALS AND METHODS

We assessed the performance of 12 residents in training whose curriculum included simulated upper GI series (study group) and 10 traditionally trained residents (control group) using a multiple-choice test, checklist procedure evaluation and diagnostic accuracy scores for 3 randomly selected simulated upper GI series. We then compared the results from the study group that had simulation curriculum to the scores for the control group using the Mann-Whitney test. We also analyzed the scores for the study group obtained prior to and after simulation curriculum using Wilcoxon signed rank test.

RESULTS

There was a significant difference in test scores (study group median = 84.5%, control group median = 67.2%, P=0.001), overall diagnostic accuracy (study group median = 100%, control group median = 50%, P=0.011) and checklist evaluation (study group median = 83.3%, control group median = 70.8%, P=0.025) for the residents in the study group who completed simulation curriculum compared with the control group. There was also a significant difference in multiple-choice test scores for the study group before and after completion of simulation curriculum (before simulation curriculum median = 56.9%, after simulation curriculum median = 84.5%, P=0.002), checklist evaluation (before simulation curriculum median = 58.3%, after simulation curriculum median = 83.3%, P=0.002) and overall diagnostic accuracy scores (before simulation curriculum median = 50%, after simulation curriculum median = 100%, P=0.024).

CONCLUSION

Radiology residents had significantly higher scores on a multiple-choice test, checklist procedure evaluation and overall diagnostic accuracy after completing a structured pediatric fluoroscopy curriculum that included simulated neonatal upper GI series and when compared to a control group of traditionally trained residents.

Congenital duodenal obstruction: causes and imaging approach

Bilious emesis is a common cause for evaluation in pediatric radiology departments. There are several causes of congenital duodenal obstruction, most of which require elective surgical correction, but the potential of malrotation with midgut volvulus demands prompt imaging evaluation. We review the various causes of congenital duodenal obstruction with an emphasis on the approach to imaging evaluation and diagnosis.

Multiple Congenital Colonic Stenosis: A Rare Gastrointestinal Malformation

Congenital colonic stenosis is a rare pediatric condition. Since 1968, only 16 cases have been reported in the literature. To the authors' knowledge, multiple congenital colonic stenosis has not been previously reported in the literature. We report the case of a 2-month-old male, presented at our Neonatal Intensive Care Unit with a suspicion of intestinal malrotation. Clinical examination revealed persistent abdominal distension. During the enema examination, the contrast medium appeared to fill the lumen of the colon up to three stenotic segments and could not proceed further. Intraoperatively we confirmed the presence of four types of colonic atresia, located in the ascending, transverse, and descending colon, respectively, plus appendix atresia. First surgical steps consisted in resection of proximal stenotic segment, appendix removal, proximal cecostomy, and distal colostomy on ascending colon in order to preserve colonic length. Histopathological examination confirmed the diagnosis of colonic stenosis. Final surgical step consisted in multiple colocolostomy and enteroplasty. A planned two-stage procedure, consisting of resection with colostomy for decompression as the first step and a later anastomosis, is recommended in order to allow bowel length preservation.

Case 1: a newborn with bilious emesis

In the introductory article of a new series geared toward pediatric radiology trainees, the radiological management of newborn bilious emesis is discussed through the details of a specific case.