Focus on cystic fibrosis and other disorders evidenced in fetuses with sonographic finding of echogenic bowel: 16-year report from Brittany, France

Gastrointestinal, Pancreatic, and Hepatic Manifestations of Cystic Fibrosis in the Newborn

Gastrointestinal, pancreatic, and hepatic signs and symptoms represent the most common presentation of early disease among patients with cystic fibrosis and may be the initial indication of disease. Regardless of whether cystic fibrosis is diagnosed early by newborn screening or later by clinical course, the impact of gastrointestinal, pancreatic, and hepatic manifestations on early life is nearly ubiquitous. Conditions strongly linked with cystic fibrosis, such as meconium ileus and pancreatic insufficiency, must be recognized and treated early to optimize both short- and long-term care. Similarly, less specific conditions such as reflux, poor weight gain, and cholestasis are frequently encountered in infants with cystic fibrosis. In this population, these conditions may present unique challenges in which early interventions may have significant influence on both short- and long-term morbidity and mortality outcomes.

The future of cystic fibrosis care: a global perspective

The past six decades have seen remarkable improvements in health outcomes for people with cystic fibrosis, which was once a fatal disease of infants and young children. However, although life expectancy for people with cystic fibrosis has increased substantially, the disease continues to limit survival and quality of life, and results in a large burden of care for people with cystic fibrosis and their families. Furthermore, epidemiological studies in the past two decades have shown that cystic fibrosis occurs and is more frequent than was previously thought in populations of non-European descent, and the disease is now recognised in many regions of the world. The Lancet Respiratory Medicine Commission on the future of cystic fibrosis care was established at a time of great change in the clinical care of people with the disease, with a growing population of adult patients, widespread genetic testing supporting the diagnosis of cystic fibrosis, and the development of therapies targeting defects in the cystic fibrosis transmembrane conductance regulator (CFTR), which are likely to affect the natural trajectory of the disease. The aim of the Commission was to bring to the attention of patients, health-care professionals, researchers, funders, service providers, and policy makers the various challenges associated with the changing landscape of cystic fibrosis care and the opportunities available for progress, providing a blueprint for the future of cystic fibrosis care. The discovery of the CFTR gene in the late 1980s triggered a surge of basic research that enhanced understanding of the pathophysiology and the genotype-phenotype relationships of this clinically variable disease. Until recently, available treatments could only control symptoms and restrict the complications of cystic fibrosis, but advances in CFTR modulator therapies to address the basic defect of cystic fibrosis have been remarkable and the field is evolving rapidly. However, CFTR modulators approved for use to date are highly expensive, which has prompted questions about the affordability of new treatments and served to emphasise the considerable gap in health outcomes for patients with cystic fibrosis between high-income countries, and low-income and middle-income countries (LMICs). Advances in clinical care have been multifaceted and include earlier diagnosis through the implementation of newborn screening programmes, formalised airway clearance therapy, and reduced malnutrition through the use of effective pancreatic enzyme replacement and a high-energy, high-protein diet. Centre-based care has become the norm in high-income countries, allowing patients to benefit from the skills of expert members of multidisciplinary teams. Pharmacological interventions to address respiratory manifestations now include drugs that target airway mucus and airway surface liquid hydration, and antimicrobial therapies such as antibiotic eradication treatment in early-stage infections and protocols for maintenance therapy of chronic infections. Despite the recent breakthrough with CFTR modulators for cystic fibrosis, the development of novel mucolytic, anti-inflammatory, and anti-infective therapies is likely to remain important, especially for patients with more advanced stages of lung disease. As the median age of patients with cystic fibrosis increases, with a rapid increase in the population of adults living with the disease, complications of cystic fibrosis are becoming increasingly common. Steps need to be taken to ensure that enough highly qualified professionals are present in cystic fibrosis centres to meet the needs of ageing patients, and new technologies need to be adopted to support communication between patients and health-care providers. In considering the future of cystic fibrosis care, the Commission focused on five key areas, which are discussed in this report: the changing epidemiology of cystic fibrosis (section 1); future challenges of clinical care and its delivery (section 2); the building of cystic fibrosis care globally (section 3); novel therapeutics (section 4); and patient engagement (section 5). In panel 1, we summarise key messages of the Commission. The challenges faced by all stakeholders in building and developing cystic fibrosis care globally are substantial, but many opportunities exist for improved care and health outcomes for patients in countries with established cystic fibrosis care programmes, and in LMICs where integrated multidisciplinary care is not available and resources are lacking at present. A concerted effort is needed to ensure that all patients with cystic fibrosis have access to high-quality health care in the future.

Predictors for surgical intervention and surgical outcomes in neonates with cystic fibrosis

BACKGROUND/PURPOSE

To identify prenatal and perinatal predictors of surgery and describe surgical findings/outcomes of neonates with Meconium Ileus (MI) secondary to Cystic Fibrosis (CF).

METHODS

Potential risk factors (prenatal bowel echogenicity, CF genotype, birthweight, prematurity and sex) for MI and surgery were examined in a retrospective cohort of neonates with CF presenting to a tertiary center between 1997 and 2015. Following univariable analysis, predictors of MI and surgery were determined using multivariable logistic regression. For surgical patients, detailed operative findings and outcomes were examined.

RESULTS

MI was diagnosed in 26/120 (21.7%) neonates with CF and 19/26 (73.0%) required surgery. Prematurity was significantly associated with increased risk of MI and operative intervention (p-value 0.022 and p-value 0.016 respectively); lower birthweight was associated with operative intervention (p-value 0.039); genotype and echogenic bowel were associated with neither. Surgical data were available for 17/19 patients; median age at surgery was 2 days (IQR1-3), 4/17 had an atresia and 6/17 received an ostomy. Median NICU and hospital stays were 34.5 and 70 days while median time on TPN and time to ostomy reversal were 28.5 and 97 days, respectively.

CONCLUSIONS

In patients with CF, prematurity and lower birthweight were identified as risk factors for meconium ileus and need for surgery. Specific genotypes and echogenic bowel were not predictors of either.

LEVEL OF EVIDENCE

Level III.

Incidence and Carrier Frequency of CFTR Gene Mutations in Pregnancies With Echogenic Bowel in Nova Scotia and Prince Edward Island

OBJECTIVE

Fetal echogenic bowel (echogenic bowel) is associated with cystic fibrosis (CF), with a reported incidence ranging from 1% to 13%. Prenatal testing for CF in the setting of echogenic bowel can be done by screening parental or fetal samples for pathogenic CFTR variants. If only one pathogenic variant is identified, sequencing of the CFTR gene can be undertaken, to identify a second pathogenic variant not covered in the standard screening panel. Full gene sequencing, however, also introduces the potential to identify variants of uncertain significance (VUSs) that can create counselling challenges and cause parental anxiety. To provide accurate counselling for families in the study population, the incidence of CF associated with echogenic bowel and the carrier frequency of CFTR variants were investigated.

METHODS

All pregnancies for which CF testing was undertaken for the indication of echogenic bowel (from Nova Scotia and Prince Edward Island) were identified (January 2007-July 2017). The CFTR screening and sequencing results were reviewed, and fetal outcomes related to CF were assessed.

RESULTS

A total of 463 pregnancies with echogenic bowel were tested. Four were confirmed to be affected with CF, giving an incidence of 0.9% in this cohort. The carrier frequency of CF among all parents in the cohort was 5.0% (1 in 20); however, when excluding parents of affected fetuses, the carrier frequency for the population was estimated at 4.1% (1 in 25). CFTR gene sequencing identified an additional VUS in two samples.

CONCLUSION

The incidence of CF in pregnancies with echogenic bowel in Nova Scotia and Prince Edward Island is 0.9%, with an estimated population carrier frequency of 4.1%. These results provide the basis for improved counselling to assess the risk of CF in the pregnancy, after parental carrier screening, using Bayesian probability. Counselling regarding VUSs should be undertaken before gene sequencing.

Adverse Perinatal Conditions Associated With Prenatally Detected Fetal Echogenic Bowel in Nova Scotia

OBJECTIVE

This study sought to estimate the association of adverse perinatal outcomes with pregnancies complicated by fetal echogenic bowel.

METHODS

Data for pregnancies complicated with echogenic bowel identified in the second trimester were derived from the tertiary referral IWK Health Centre (Halifax, NS) Viewpoint Ultrasound Database augmented by medical chart review. The study was undertaken between 2003 and 2014. Rates of positive cytomegalovirus and toxoplasmosis infection were determined using maternal serology and amniocentesis results. Rates of intrauterine growth restriction, abnormal karyotype, cystic fibrosis, antenatal bleeding, and bowel abnormalities were also determined. Neonatal information included newborn urine culture results and postnatal genetic testing. Univariate analyses compared rates of infection with isolated echogenic bowel and echogenic bowel with other ultrasound findings, with statistical significance set at P <0.05.

RESULTS

There were 422 pregnancies identified prenatally with echogenic bowel (82% had isolated echogenic bowel). Of these, 92 (22%) had at least one of the foregoing associated abnormalities. Three percent of women had serologic test results positive for cytomegalovirus or toxoplasmosis, with <1% documented newborn infections. Cystic fibrosis and other genetic diagnoses were observed in 8%, intrauterine growth restriction in 14%, antenatal bleeding in 19%, and bowel abnormalities in 3% of the cases of echogenic bowel. Pregnancies with isolated echogenic bowel had an 80% reduction in risk for these significant outcomes, in contrast to a four- to 11-fold increased risk of specific outcomes when additional ultrasound findings were present.

CONCLUSION

An overall rate of adverse conditions of 22% with prenatally detected echogenic bowel serves to inform women and health care providers and emphasizes the importance of careful screening fetal ultrasound studies and timely referral for comprehensive assessment with findings of echogenic bowel for evaluation for associated findings.

A Retrospective Study of Cytogenetic Results From Amniotic Fluid in 5328 Fetuses With Abnormal Obstetric Sonographic Findings

OBJECTIVES

The purpose of this study was to evaluate the diagnostic utility of karyotype analysis of amniotic fluid for fetuses with abnormal sonographic findings and to determine the detection rates of abnormal karyotypes.

METHODS

We conducted a retrospective study of 5328 fetuses with abnormal sonographic findings in the first or second trimester enrolled from October 1998 and September 2015. Cytogenetic results from amniotic fluid were obtained in all of these pregnancies. Sonographic abnormalities were stratified according to anatomic system involvement.

RESULTS

A total of 238 abnormal karyotypes were encountered in the 5328 fetuses (4.5%). The highest rate of chromosomal anomalies was in fetuses with structural abnormalities in multiple organ systems (25.7%), followed by an abnormal amniotic fluid volume (7.9%), structural abnormalities in a single system (7.3%), multiple nonstructural anomalies (7.2%), isolated placental abnormalities (7.1%), and isolated soft markers for aneuploidy (2.4%; P < .01). Among abnormalities in a single system, gastrointestinal and neck/body fluids had particularly high detection rates (26.1% and 26.2%, respectively). A detailed analysis suggested that the probability of an abnormal karyotype among every anatomic system was statistically significant (P < .01). This study identified several common indications with extremely high abnormal rates: duodenal atresia (53.1%), holoprosencephaly (48.8%), fetal hydrops (39.5%), cerebellar hypoplasia (32.0%), cystic hygroma (31.5%), absent/short nasal bone (11.0%), and bilateral choroid plexus cysts (8.5%).

CONCLUSIONS

Cytogenetic analysis has important clinical utility in a wide range of settings, such as prenatal diagnosis. For fetuses with indications of a highly abnormal detection rate, karyotype analysis should be suggested.

Beyond pancreatic insufficiency and liver disease in cystic fibrosis

Cystic fibrosis is a life shortening hereditary disease, primarily leading to progressive pulmonary infection and exocrine pancreatic dysfunction. Several gastrointestinal complications other than malabsorption can arise during the disease course and with the progressively increasing life span of patients with CF; new and more rare complications are being recognized. We review the literature on gastrointestinal manifestations in CF, excluding the liver and pancreas.

CONCLUSION

We describe the clinical presentation and treatment of more common conditions like gastroesophageal reflux, small intestinal bacterial overgrowth, intussusception, meconium ileus, distal intestinal obstruction syndrome, and constipation, and we also discuss what is known on celiac disease, appendicitis, fibrosing colonopathy, inflammation and inflammatory bowel disease and gastrointestinal cancer.

WHAT IS KNOWN

• Gastrointestinal complications arise early in the course of the disease and have a severe impact on the quality of life of the patients. What is New: • This review is a concise summary of the current literature on gastrointestinal complications of cystic fibrosis. • We focused on clinical presentation and diagnostic investigations and provide a comprehensive resume of the current treatment options.

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.

The effect of associated structural malformations in the prediction of chromosomal abnormality risk of fetuses with echogenic bowel

OBJECTIVE

Our aim is to determine the frequency of chromosomal abnormalities and also to identify the role of structural malformations on the chromosomal abnormality risk among fetuses with echogenic bowel.

METHODS

Over a 6-year period fetuses with echogenic bowel (FEB) were retrospectively evaluated. The pregnancies with intra-amniotic bleeding history, congenital infection, cystic fibrosis and intrauterine growth retardation were excluded from the study. Types and frequency of sonographically detected fetal malformations were identified. Chromosomal abnormality incidences according to association with soft markers and major fetal abnormalities were compared.

RESULTS

Of the 281 fetuses with echogenic bowel, 105 (37.37%) were isolated, 78 (27.76%) were associated with soft markers and 98 (34.87%) were associated with major abnormalities. There were 30 (10.7%) fetuses with abnormal karyotypes. The chromosomal abnormality rate of the groups of isolated FEB, FEB + soft markers and FEB + major abnormalities were 6.7%, 7.7% and 17.4%, respectively.

CONCLUSIONS

Chromosomal abnormality risk in fetuses with echogenic bowel should be evaluated according to additional sonographic findings. Association of structural malformations increases the chromosomal abnormality risk, although this risk is not significant with the presence of soft markers alone.

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.

[Neonatal outcome of fetal hyperechogenic bowel]

OBJECTIVE

Echogenic bowel (EB) represents 1 % of pregnancy and is a risk factor of fetal pathology (infection, cystic fibrosis, aneuploidy). The aim of our study was to determine the fetuses' outcomes with isolated EB.

PATIENTS AND METHODS

This is a retrospective study of all patients who presented singleton gestations with a fetal isolated echogenic bowel between 2004 and 2011 in two prenatal diagnosis centers. Search of aneuploidy, infection and cystic fibrosis was systematically proposed as well as an ultrasound monitoring.

RESULTS

On 109 fetus addressed for isolate echogenic bowel five had other signs associated and 74 had a real isolated echogenic bowel (without dilatation, calcification, intrauterine growth restriction). In 30 cases, the EB was not found. Eighty-five percent of the patients had in the first trimester a screening for trisomy 21. None fetus with isolated EB had trisomy, infection or cystic fibrosis. One fetus died in utero and one newborn died of a metabolic disease without digestive repercussions.

DISCUSSION AND CONCLUSION

The risk of trisomy 21 and the risk to have a serious disease appear low for the fetus with EB. It does not seem necessary to propose a systematic amniocentesis in case of isolated echogenic bowel.

Follow-up of sonographically detected soft markers for fetal aneuploidy

Sonographic soft markers of fetal Down syndrome were first reported in the 1980s. With improvements in aneuploidy screening, detection rates of 90% and higher are possible, and such screening is offered to women of all ages. The utility of sonographic detection and reporting of soft markers, particularly to women at low risk of fetal aneuploidy, is controversial. Some soft markers have no additional significance beyond an association with aneuploidy, while some potentially indicate other pathology, and therefore require sonographic follow-up or other evaluation. The definitions of soft markers vary among reported series, and any practice using such markers to adjust the risk of aneuploidy should carefully determine the most appropriate definitions as well as likelihood ratios and how to apply these in practice.

A classification model relative to splicing for variants of unknown clinical significance: application to the CFTR gene

Molecular diagnosis of cystic fibrosis and cystic fibrosis transmembrane regulator (CFTR)-related disorders led to the worldwide identification of nearly 1,900 sequence variations in the CFTR gene that consist mainly of private point mutations and small insertions/deletions. Establishing their effect on the function of the encoded protein and therefore their involvement in the disease is still challenging and directly impacts genetic counseling. In this context, we built a decision tree following the international guidelines for the classification of variants of unknown clinical significance (VUCS) in the CFTR gene specifically focused on their consequences on splicing. We applied general and specific criteria, including comprehensive review of literature and databases, familial genetics data, and thorough in silico studies. This model was tested on 15 intronic and exonic VUCS identified in our cohort. Six variants were classified as probably nonpathogenic considering their impact on splicing and eight as probably pathogenic, which include two apparent missense mutations. We assessed the validity of our method by performing minigenes studies and confirmed that 93% (14/15) were correctly classified. We provide in this study a high-performance method that can play a full role in interpreting the results of molecular diagnosis in emergency context, when functional studies are not achievable.

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

PURPOSE

Meconium ileus (MI) is the earliest clinical manifestation of cystic fibrosis (CF), occurring in up to 20% of patients with CF. Our aim was to review and integrate current knowledge about the diagnosis and management of fetuses and neonates with MI that may aid the pediatric surgeon in caring for these patients.

METHODS

We identified areas of interest including pathophysiology, prenatal diagnosis, nonoperative and operative management, postoperative management, and prognosis. We performed a Medline search using the search term meconium ileus for English language articles published in the last 20 years. We reviewed reference lists to identify other articles of historical significance.

RESULTS

Meconium ileus is primarily associated with CF transmembrane (conductance) regulator mutations F508del, G542X, W1282X, R553X, and G551D, and modifier genes have been found to explain approximately 17% of the phenotypic variability. Mouse, pig, and ferret models for CF demonstrate neonatal bowel obstruction mimicking MI. Sonographic findings of hyperechoic masses and dilated bowel in a high-risk fetus are suggestive of MI. Less than 7% of low-risk fetuses with hyperechoic bowel will have MI. Contemporary series of noninvasive management with Gastrografin enema report success rates of 36% to 39%, significantly lower than historical values. The optimal surgical technique remains controversial, although primary anastomosis results in surgical complication rates between 21% and 31%, higher than those noted with delayed anastomosis. Pulmonary function for patients with CF and MI at 15 and 25 years old is similar to those without MI, although height and weight percentiles may be lower.

CONCLUSIONS

This review for pediatric surgeons presents an examination of the literature and synthesizes current information about the pathophysiology, prenatal diagnosis, nonoperative and operative management, postoperative management, and prognosis of the patient with CF and MI.

Nonvisualization of fetal gallbladder increases the risk of cystic fibrosis

OBJECTIVE

The aim of our study is to evaluate the prevalence of cystic fibrosis (CF) in fetuses referred for genetic testing because of ultrasonographic sign (nonvisualized fetal gallbladder--NVFGB).

METHOD

We reviewed the results of CFTR gene analysis over the period 2002 to 2009 in all consecutive cases referred because of NVFGB in Western France. We correlated these data with the presence of a more classical ultrasonographic finding (fetal echogenic bowel - FEB).

RESULTS

Cystic fibrosis was diagnosed in 5 of the 37 fetuses with NVFGB (13.5%, 95% confidence interval (CI): [2.5%; 24.5%]) and in only 9 of the 229 other cases referred because of FEB (3.9%, 95% CI: [3.2%; 14.7%]). In our series, all CF-affected fetuses with NVFGB also had FEB. The risk of CF was 11.6-fold higher in fetuses with both indications (NVFGB + FEB) than in fetuses with isolated FEB (45.5% vs 3.9%, RR = 11.6, 95% CI: [4.7%; 28.8%], p = 0.0001). We also estimated that the residual risk of CF was less than 1 in 68 (1.5%) when a single mutation was identified in the fetus by our molecular protocol.

CONCLUSION

Ultrasonographic evidence of NVFGB is an additional risk factor for CF in cases with FEB.

Echogenic bowel on second-trimester ultrasonography: evaluating the risk of adverse pregnancy outcome

OBJECTIVE

To estimate if echogenic bowel diagnosed on second-trimester ultrasonography has an independent risk association with intrauterine growth restriction (IUGR) and intrauterine fetal demise.

METHODS

This is a retrospective cohort study of all patients with singleton gestations who presented to our institution for second-trimester ultrasonography between 1990 and 2008. Study groups were defined by the presence or absence of echogenic bowel. Primary outcomes were IUGR, defined as birth weight less than the 10th percentile for gestational age and intrauterine fetal demise at 20 weeks or more of gestation. Univariable and multivariable logistic regression analyses were used to estimate the risk of intrauterine fetal demise and IUGR in fetuses with echogenic bowel. Analyses were repeated after excluding cases of aneuploidy, cytomegalovirus (CMV) infection, other major congenital anomalies, and abnormal second-trimester serum screening results.

RESULTS

Of 64,048 patients, the incidence of echogenic bowel was 0.4%. Of these, echogenic bowel was an isolated finding in 188 (72.3%) cases. There were 579 (0.9%) cases of intrauterine fetal demise and 8,173 (12.8%) cases of IUGR in the entire cohort. After excluding cases of aneuploidy and CMV infection, the incidence of intrauterine fetal demise was 7.3% in the echogenic bowel group compared with 0.9% in the nonechogenic bowel group, translating to an absolute risk increase of 6.4%. The incidence of IUGR in the echogenic bowel group was 19.5% compared with 12.9% in the nonechogenic bowel group (absolute risk increase, 6.6%). After controlling for potential confounders, echogenic bowel was significantly associated with both intrauterine fetal demise (adjusted odds ratio [OR] 9.6, 95% confidence interval [CI] 5.8-15.9) and IUGR (adjusted OR 2.1, 95% CI 1.5-2.9). This risk association remained significant even when evaluating echogenic bowel as an isolated sonographic finding.

CONCLUSION

The presence of echogenic bowel on ultrasonography is independently associated with an increased risk for both IUGR and intrauterine fetal demise. Serial growth assessment and antenatal testing may be warranted in these patients.