A review of pathophysiology and management of fetuses and neonates with meconium ileus for the pediatric surgeon

Comparative Effectiveness of Imaging Modalities for the Diagnosis of Intestinal Obstruction in Neonates and Infants:: A Critically Appraised Topic

RATIONALE AND OBJECTIVES

The purpose of this study was to critically appraise and compare the diagnostic performance of imaging modalities that are used for the diagnosis of upper and lower gastrointestinal (GI) tract obstruction in neonates and infants.

METHODS

A focused clinical question was constructed and the literature was searched using the patient, intervention, comparison, outcome method comparing radiography, upper GI contrast study, and ultrasound in the detection of upper GI tract obstruction such as duodenal atresia and stenosis, jejunal and ileal atresia, and malrotation and volvulus. The same methods were used to compare radiography and contrast enema in the detection of lower GI tract obstruction such as meconium plug syndrome, meconium ileus, Hirschsprung disease, and imperforate anus. Retrieved articles were appraised and assigned a level of evidence based on the Oxford University Centre for Evidence-Based Medicine hierarchy of validity for diagnostic studies.

RESULTS

There were no sensitivities/specificities available for the imaging diagnosis of duodenal atresia or stenosis, jejunal or ileal atresias, meconium plug, and meconium ileus or for the use of cross-table lateral radiography for the diagnosis of rectal pouch distance from skin in imperforate anus. The retrieved sensitivity for the detection of malrotation on upper GI contrast study is 96%, and the sensitivity for the diagnosis of midgut volvulus on upper GI contrast study is 79%. The retrieved sensitivity and specificity for the detection of malrotation with volvulus on ultrasound were 89% and 92%, respectively. The retrieved sensitivity and specificity for the detection of Hirschsprung disease on contrast enema were 70% and 83%, respectively. The retrieved sensitivity of invertogram for the diagnosis of rectal pouch distance from skin in imperforate anus is 27%. The retrieved sensitivities of perineal ultrasound and colostography for the diagnosis of rectal pouch distance from skin in imperforate anus were 86% and 100%, respectively.

CONCLUSIONS

There is limited evidence for the imaging diagnosis of duodenal atresia and stenosis, jejunal and ileal atresias, meconium plug, meconium ileus, and imperforate anus, with recommended practice based mainly on low-quality evidence or expert opinion. The available evidence supports the use of upper GI contrast study for the diagnosis of malrotation and volvulus, with ultrasound as an adjunct to diagnosis. Contrast enema is useful in the investigation of suspected Hirschsprung disease, but a negative study does not outrule the condition. Colostography is the investigation of choice for the work-up of infants with complex anorectal malformations before definitive surgical repair.

Gastrointestinal Tract Perforation in the Newborn and Child: Imaging Assessment

Gastrointestinal tract perforation can arise from various underlying etiologies ranging from congenital causes to ingested foreign bodies in the pediatric patient population. Imaging assessment in patients with suspected gastrointestinal tract perforation plays a central role in making the diagnosis and follow-up evaluation. This article reviews the more common etiologies of gastrointestinal tract perforation in pediatric patients, their imaging manifestations, and strategies for imaging assessment to assist the radiologist in arriving at a timely and accurate diagnosis.

Computed Tomography (CT) Scanning Facilitates Early Identification of Neonatal Cystic Fibrosis Piglets

Background

Cystic Fibrosis (CF) is the most prevalent autosomal recessive disease in the Caucasian population. A cystic fibrosis transmembrane conductance regulator knockout (CFTR-/-) pig that displays most of the features of the human CF disease has been recently developed. However, CFTR^-/- pigs presents a 100% prevalence of meconium ileus that leads to death in the first hours after birth, requiring a rapid diagnosis and surgical intervention to relieve intestinal obstruction. Identification of CFTR^-/- piglets is usually performed by PCR genotyping, a procedure that lasts between 4 to 6 h. Here, we aimed to develop a procedure for rapid identification of CFTR^-/- piglets that will allow placing them under intensive care soon after birth and immediately proceeding with the surgical correction.

Methods and Principal Findings

Male and female CFTR^+/- pigs were crossed and the progeny was examined by computed tomography (CT) scan to detect the presence of meconium ileus and facilitate a rapid post-natal surgical intervention. Genotype was confirmed by PCR. CT scan presented a 94.4% sensitivity to diagnose CFTR^-/- piglets. Diagnosis by CT scan reduced the birth-to-surgery time from a minimum of 10 h down to a minimum of 2.5 h and increased the survival of CFTR^-/- piglets to a maximum of 13 days post-surgery as opposed to just 66 h after later surgery.

Conclusion

CT scan imaging of meconium ileus is an accurate method for rapid identification of CFTR^-/- piglets. Early CT detection of meconium ileus may help to extend the lifespan of CFTR^-/- piglets and, thus, improve experimental research on CF, still an incurable disease.

Prenatal diagnosis of gastric and small bowel atresia: a case series and review of the literature

OBJECTIVE

To describe seven cases of gastrointestinal tract (GIT) obstructions and to report a skewed review of the literature.

METHODS

We performed a search of our permanent perinatal database about cases with prenatal ultrasound and MRI diagnosis of gastrointestinal tract obstructions between 2006 and 2013. All cases were followed until hospital discharge and pre-natal diagnosis were confirmed by fetal MRI, postnatal imaging and/or intra-operative findings. Maternal age, parity, gestational age at diagnosis, ultrasound findings, gestational age at delivery, Apgar scores at 1 and 5 min and postnatal outcome have been recorded.

RESULTS

We identified seven cases of gastric and small bowel atresia. Karyotype was normal in six cases and abnormal in one co-twin [46,XY dup (20) (qq13.1q13.3)dn] of a dichorionic-diamniotic pregnancy. The mean ± SD for maternal age, gestational age at diagnosis, gestational at delivery, birth weight and Apgar scores at 1 and 5 min were 30.8 ± 4.8 years, 29.8 ± 3.7 weeks, 2507.5 ± 727.5 g and 5.6 ± 2.1, 7.6 ± 1.6, respectively. All fetuses' undergone surgical procedures in the postnatal period and all of them were discharged live from the hospital.

CONCLUSION

Prompted antenatal detection of gastrointestinal tract obstruction using ultrasound proved to be diagnostic in all cases. Fetal MRI aid was a useful complementary diagnostic investigation. Correct pre-natal diagnosis allows adequate counseling, delivery planning and management care by a multidisciplinary team.

Meconium-related ileus in very low birth weight and extremely low birth weight infants: immediate and one-year postoperative outcomes

PURPOSE

One of the major causes of bowel obstruction in extremely premature infants is a meconium obstruction. However, there are many challenges not only in the recognition and diagnosis, but also in the management of meconium obstruction. This study aimed to find perioperative clinical features and determine the postoperative course of meconium-related ileus in very low birth weight (VLBW) and extremely low birth weight (ELBW) infants.

METHODS

We retrospectively reviewed the clinical data of premature infants (n = 11, VLBW infnats; n = 16, ELBW infants) with a meconium-related ileus who underwent operation for intractable ileus between January 2009 and May 2013.

RESULTS

The average duration of conservative management was longer and postnatal age was older in ELBW infants than VLBW infants: 19.9 days vs. 11.5 days and 34.9 days vs. 19.2 days. The immediate postoperative course (day that beginning feeding and full feeding) was not significantly different based on birth weight, but the ELBW infants had slightly higher mortality. At 12 months of corrected age after operation, both average body weight and average height was below 10th percentile for growth in most infants (61.1%).

CONCLUSION

There was a slightly high mortality in the ELBW infants, but two groups did not experience significant differences in the immediate postoperative course of meconium-related ileus. Nevertheless, considering their growth patterns, it is necessary to do a close follow-up and more aggressive nutritional management to achieve optimal growth and development in both patient groups.

Prevalence of meconium ileus marks the severity of mutations of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene

RATIONALE

Meconium ileus (MI) is a perinatal complication in cystic fibrosis (CF), which is only minimally influenced by environmental factors. We derived and examined MI prevalence (MIP) scores to assess CFTR phenotype-phenotype correlation for severe mutations.

METHOD

MIP scores were established using a Canadian CF population (n = 2,492) as estimates of the proportion of patients with MI among all patients carrying the same CFTR mutation, focusing on patients with p.F508del as the second allele. Comparisons were made to the registries from the US CF Foundation (n = 43,432), Italy (Veneto/Trentino/Alto Adige regions) (n = 1,788), and Germany (n = 3,596).

RESULTS

The prevalence of MI varied among the different registries (13-21%). MI was predominantly prevalent in patients with pancreatic insufficiency carrying "severe" CFTR mutations. In this severe spectrum MIP scores further distinguished between mutation types, for example, G542X (0.31) with a high, F508del (0.22) with a moderate, and G551D (0.08) with a low MIP score. Higher MIP scores were associated with more severe clinical phenotypes, such as a lower forced expiratory volume in 1 second (P = 0.01) and body mass index z score (P = 0.04).

CONCLUSIONS

MIP scores can be used to rank CFTR mutations according to their clinical severity and provide a means to expand delineation of CF phenotypes.Genet Med 18 4, 333-340.

Defective goblet cell exocytosis contributes to murine cystic fibrosis-associated intestinal disease

Cystic fibrosis (CF) intestinal disease is associated with the pathological manifestation mucoviscidosis, which is the secretion of tenacious, viscid mucus that plugs ducts and glands of epithelial-lined organs. Goblet cells are the principal cell type involved in exocytosis of mucin granules; however, little is known about the exocytotic process of goblet cells in the CF intestine. Using intestinal organoids from a CF mouse model, we determined that CF goblet cells have altered exocytotic dynamics, which involved intrathecal granule swelling that was abruptly followed by incomplete release of partially decondensated mucus. Some CF goblet cells exhibited an ectopic granule location and distorted cellular morphology, a phenotype that is consistent with retrograde intracellular granule movement during exocytosis. Increasing the luminal concentration of bicarbonate, which mimics CF transmembrane conductance regulator-mediated anion secretion, increased spontaneous degranulation in WT goblet cells and improved exocytotic dynamics in CF goblet cells; however, there was still an apparent incoordination between granule decondensation and exocytosis in the CF goblet cells. Compared with those within WT goblet cells, mucin granules within CF goblet cells had an alkaline pH, which may adversely affect the polyionic composition of the mucins. Together, these findings indicate that goblet cell dysfunction is an epithelial-autonomous defect in the CF intestine that likely contributes to the pathology of mucoviscidosis and the intestinal manifestations of obstruction and inflammation.

European Cystic Fibrosis Society Standards of Care: Best Practice guidelines

Specialised CF care has led to a dramatic improvement in survival in CF: in the last four decades, well above what was seen in the general population over the same period. With the implementation of newborn screening in many European countries, centres are increasingly caring for a cohort of patients who have minimal lung disease at diagnosis and therefore have the potential to enjoy an excellent quality of life and an even greater life expectancy than was seen previously. To allow high quality care to be delivered throughout Europe, a landmark document was published in 2005 that sets standards of care. Our current document builds on this work, setting standards for best practice in key aspects of CF care. The objective of our document is to give a broad overview of the standards expected for screening, diagnosis, pre-emptive treatment of lung disease, nutrition, complications, transplant/end of life care and psychological support. For comprehensive details of clinical care of CF, references to the most up to date European Consensus Statements, Guidelines or Position Papers are provided in Table 1. We hope that this best practice document will be useful to clinical teams both in countries where CF care is developing and those with established CF centres.

Coexistence of meconium ileus with duodenal atresia and trisomy 21 in a newborn: a case report

The coexistence of duodenal atresia (DA) may mask the antenatal ultrasound findings of meconium ileus (MI) and delay its postnatal diagnosis. We report a rare case of MI in a newborn infant diagnosed antenatally to have trisomy 21 and DA. The diagnosis of MI was only established intraoperatively after the patient showed persistent signs of intestinal obstruction following the surgical repair of the DA.

Integration of an OWL-DL knowledge base with an EHR prototype and providing customized information

When clinicians use electronic health record (EHR) systems, their ability to obtain general knowledge is often an important contribution to their ability to make more informed decisions. In this paper we describe a method by which an external, formal representation of clinical and molecular genetic knowledge can be integrated into an EHR such that customized knowledge can be delivered to clinicians in a context-appropriate manner.Web Ontology Language-Description Logic (OWL-DL) is a formal knowledge representation language that is widely used for creating, organizing and managing biomedical knowledge through the use of explicit definitions, consistent structure and a computer-processable format, particularly in biomedical fields. In this paper we describe: 1) integration of an OWL-DL knowledge base with a standards-based EHR prototype, 2) presentation of customized information from the knowledge base via the EHR interface, and 3) lessons learned via the process. The integration was achieved through a combination of manual and automatic methods. Our method has advantages for scaling up to and maintaining knowledge bases of any size, with the goal of assisting clinicians and other EHR users in making better informed health care decisions.

Intestinal complications of cystic fibrosis

PURPOSE OF REVIEW

The article reviews advances in gastrointestinal aspects of cystic fibrosis (CF) published in the literature over the past year, and highlights new and interesting research.

RECENT FINDINGS

Animal models can be used to understand the pathophysiology of gastrointestinal complications in CF. The CF mouse is useful for studying distal intestinal obstruction, dysmotility and dysbiosis, and the CF pig model has helped us better understand meconium ileus and pancreatic and hepatobiliary secretory problems. Studies in humans help elucidate the evolution of pancreatic insufficiency, how reflux may lead to lung disease, problems with intestinal dysmotility, mechanisms leading to pancreatitis and the increased prevalence of gastrointestinal cancer. Biomarkers are shedding light on CF-related liver disease. Rectal biopsies can help in diagnosis and in studying new drugs for CF.

SUMMARY

Gastrointestinal complications of CF are likely to be seen with increasing frequency as patients with CF lead longer lives. CF animal models and modern research techniques are providing new insights into extrapulmonary complications. CF clinicians should be familiar with diagnosis and management of common gastrointestinal complications and should build bridges with specialists so that referrals can be made when needed.

Prenatal diagnosis and management of an intestinal volvulus with meconium ileus and peritonitis

Fetal intestinal volvulus is a rare but serious finding with a high risk of potential life threatening fetal complications. Delay in diagnosis or treatment can increase mortality and morbidity. We report a case of mild fetal bowel dilatation at 30 weeks of gestation and intestinal volvulus presented by the 'whirl-sign', intestinal perforation and meconium peritonitis with fetal ascites and polyhydramnios at 33 weeks of gestation. This case emphasizes the role of examination of the bowel in third trimester ultrasound and the importance of quick decision to delivery and interdisciplinary perinatal management at suspected fetal volvulus with bowel necrosis and intraabdominal bleeding.

Apparent Homozygosity of p.Phe508del in CFTR due to a Large Gene Deletion of Exons 4-11

We report a classic cystic fibrosis (CF) boy with a large deletion of exons 4-11 in the cystic fibrosis transmembrane conductance regulator (CFTR) gene on one allele and p.Phe508del in exon 10 on the second allele. Both parents of Georgian and Ukrainian background had no personal or family history of the disease. The initial molecular diagnostic investigation identified the patient as homozygous for the p.Phe508del and not compatible with his parent's genetic status. The possibility of nonpaternity or uniparental disomy (UPD7) was investigated and excluded using microsatellite analysis of highly polymorphic markers on chromosome 7. Array-CGH was also performed on the patient and revealed a male profile with a subtle deletion within the CFTR gene on the long arm (q-arm) of chromosome 7 (7q31.2). The deletion was confirmed by MLPA extending from probe L02380 to probe L14978 (28.7 kb) and that was inherited from his father, while p.PheF508del was inherited from his mother. These data highlight the need for additional testing for large deletions in patients with apparent homozygosity for a mutated CFTR allele that do not match the carrier status of the parents. Not testing can lead to misdiagnosis and misinterpretation of mutation carrier status and the expected penetrance of the disorder.

Gastrointestinal surgery in cystic fibrosis: a 20-year review

OBJECTIVES

The purpose of this study was to evaluate outcomes of the surgical management for meconium ileus (MI) and Distal Intestinal Obstruction Syndrome (DIOS) in Cystic Fibrosis (CF).

METHODS

Children born between 1990 and 2010 were identified using a regional CF database. Retrospective case note analysis was performed. Outcome measures for MI were mortality, relaparotomy rate, length of stay (LOS), time on parental nutrition (TP), and time to full feeds (TFF). Outcome measures for DIOS were: age of onset, number of episodes, and need for laparotomy.

RESULTS

Seventy-five of 376 neonates presented with MI. Fifty-four (92%) required laparotomy. Contrast enema decompression was attempted in nineteen. There were no post-operative deaths. Thirty-nine (72%) neonates with MI were managed with stomas. LOS was longer in those managed with stomas (p=0.001) and in complex MI (p=0.002). Thirty-five patients were treated for DIOS. Twenty-five patients were managed with gastrograffin. Ten patients underwent surgical management of DIOS. Overall, MI did not predispose to later development of DIOS. There was a significantly greater incidence of laparotomy for DIOS in children who had MI.

CONCLUSION

The proportion of neonates with complex meconium ileus was high (49%) and may explain the infrequent utilisation of radiological decompression. Complex MI or management with stomas both significantly increase LOS. Re-laparotomy rate is high (22%) in MI irrespective of the type of management. DIOS is not a benign condition, particularly when the child has had previous abdominal surgery. Early referral to a surgical team is essential in these children.

Advances in Hirschsprung disease genetics and treatment strategies: an update for the primary care pediatrician

Hirschsprung disease (HSCR) is a multigenic condition with variable presentation. Most commonly, it presents in the neonatal period as a functional intestinal obstruction secondary to failure of caudal migration of the enteric nervous system. Classically, this manifests as dilated proximal bowel and constricted distal bowel with absent ganglia and hypertrophic nerve trunks. When recognized early, medical and surgical therapies can be instituted to minimize associated morbidity and mortality. This article reviews current understanding of the etiology of HSCR, its multigenic associations, the historical evolution of HSCR diagnosis and treatment, and current HSCR therapies.

Molecular testing for cystic fibrosis carrier status practice guidelines: recommendations of the National Society of Genetic Counselors

PURPOSE

To provide practice recommendations for genetic counselors whose clients are considering cystic fibrosis (CF) carrier testing or seeking information regarding CF molecular test results. The goals of these recommendations are to: 1) Provide updated information about the natural history, diagnosis, and treatment of CF and related conditions. 2) Supplement genetic counselors' knowledge and understanding of the available carrier screening and diagnostic testing options. 3) Describe the current state of genotype/phenotype correlations for CFTR mutations and an approach to interpreting both novel and previously described variants. 4) Provide a framework for genetic counselors to assist clients' decision-making regarding CF carrier testing, prenatal diagnosis, and pregnancy management. Disclaimer The practice guidelines of the National Society of Genetic Counselors (NSGC) are developed by members of the NSGC to assist genetic counselors and other health care providers in making decisions about appropriate management of genetic concerns; including access to and/or delivery of services. Each practice guideline focuses on a clinical or practice-based issue, and is the result of a review and analysis of current professional literature believed to be reliable. As such, information and recommendations within the NSGC practice guidelines reflect the current scientific and clinical knowledge at the time of publication, are only current as of their publication date, and are subject to change without notice as advances emerge.In addition, variations in practice, which take into account the needs of the individual patient and the resources and limitations unique to the institution or type of practice, may warrant approaches, treatments and/or procedures that differ from the recommendations outlined in this guideline. Therefore, these recommendations should not be construed as dictating an exclusive course of management, nor does the use of such recommendations guarantee a particular outcome. Genetic counseling practice guidelines are never intended to displace a health care provider's best medical judgment based on the clinical circumstances of a particular patient or patient population.Practice guidelines are published by NSGC for educational and informational purposes only, and NSGC does not "approve" or "endorse" any specific methods, practices, or sources of information.

Intestinal obstruction secondary to adhesions in an infant with cystic fibrosis

We report the case of a 9-week-old boy with cystic fibrosis (CF) who presented with intestinal obstruction. He was initially diagnosed with distal intestinal obstruction syndrome (DIOS) and started on laxatives and gastrograffin. This conservative management was unsuccessful and he therefore underwent an exploratory laparotomy. Despite not having undergone any previous surgery, extensive intra-abdominal adhesions were identified as the cause of the intestinal obstruction. The only previous abdominal pathology occurred in the neonatal period prior to his diagnosis of CF, when he was managed conservatively for possible necrotising enterocolitis. We hypothesise that this episode was associated with a subclinical bowel perforation that led to the formation of intra-abdominal adhesions. Although DIOS is the commonest cause of intestinal obstruction in children with CF, this case highlights that surgical causes should always be considered. It also demonstrates that the intra-abdominal adhesions can occur in the absence of previous surgery.

Intestinal CFTR expression alleviates meconium ileus in cystic fibrosis pigs

Cystic fibrosis (CF) pigs develop disease with features remarkably similar to those in people with CF, including exocrine pancreatic destruction, focal biliary cirrhosis, micro-gallbladder, vas deferens loss, airway disease, and meconium ileus. Whereas meconium ileus occurs in 15% of babies with CF, the penetrance is 100% in newborn CF pigs. We hypothesized that transgenic expression of porcine CF transmembrane conductance regulator (pCFTR) cDNA under control of the intestinal fatty acid-binding protein (iFABP) promoter would alleviate the meconium ileus. We produced 5 CFTR-/-;TgFABP>pCFTR lines. In 3 lines, intestinal expression of CFTR at least partially restored CFTR-mediated anion transport and improved the intestinal phenotype. In contrast, these pigs still had pancreatic destruction, liver disease, and reduced weight gain, and within weeks of birth, they developed sinus and lung disease, the severity of which varied over time. These data indicate that expressing CFTR in intestine without pancreatic or hepatic correction is sufficient to rescue meconium ileus. Comparing CFTR expression in different lines revealed that approximately 20% of wild-type CFTR mRNA largely prevented meconium ileus. This model may be of value for understanding CF pathophysiology and testing new preventions and therapies.

Gastrointestinal complications of cystic fibrosis

The cystic fibrosis transmembrane regulator protein (CFTR) is an ion channel in the apical surface of epithelial membranes that regulates other ion channels. Dysfunction of CFTR leads to the clinical entity of CF when mutations in CFTR are inherited in an autosomal recessive fashion. Although airway obstruction, inflammation, and infection are usually the most serious consequences of CFTR dysfunction because they lead to respiratory failure, CFTR dysfunction affects the intestinal tract and the pancreatic and hepatobiliary ducts in a similar fashion, leading to significant morbidity. This review outlines pathophysiology and common gastrointestinal ailments in the CF population along with current medical and surgical management.