A population-based study of congenital diaphragmatic hernia

A new, easy, and safe suturing technique for laparoscopic repair of Morgagni hernias

Laparoscopic repair is gaining attention as a minimally invasive surgical option for children with Morgagni hernias. There are very few reports in the literature in which different suturing techniques are described. In this report, the authors detail a new, easy, and safe suturing technique used in the laparoscopic repair of a Morgagni hernia in a five-and-a-half-month-old baby.

Outcome in fetuses with isolated congenital diaphragmatic hernia with increased nuchal translucency thickness in first trimester

OBJECTIVE

To examine the possible association between increased nuchal translucency (NT) thickness in the first trimester and perinatal outcome in isolated congenital diaphragmatic hernia (CDH).

METHODS

We conducted a retrospective study between January 2004 and June 2010. The database was searched to identify all consecutive cases of CDH referred to the fetal medicine center of Necker Hospital in Paris. Enlarged NT was defined above the 95th centile. Only children born alive with an isolated CDH were selected for the analysis of prognostic factors. We also studied the correlation between NT thickness in the first trimester and lung-to-head ratio, observed to expected lung area-to-head ratio, lung volume estimated by magnetic resonance imaging, and other prenatal features of intrathoracic compression.

RESULTS

Seventy-one cases of isolated CDH were available. The fetal NT was above the 95th centile in 9 of the 71 cases. Neonatal death occurred in 7/9 (78%) cases with enlarged NT, compared with 24/62 (38%) with normal NT (P = 0.035). Enlarged NT was significantly associated with prenatal features of intrathoracic compression.

CONCLUSION

Enlarged NT thickness in CDH is associated with a poor outcome and is related to an early intrathoracic compression.

Developmental and genetic aspects of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a frequent occurring cause of neonatal respiratory distress and occurs 1 in every 3,000 liveborns. Ventilatory support and pharmaceutical treatment of the co-occurring lung hypoplasia and pulmonary hypertension are insufficient in, respectively, 20% of isolated cases and 60% of complex ones leading to early perinatal death. The exact cause of CDH remains to be identified in the majority of human CDH patients and prognostic factors predicting treatment refraction are largely unknown. Their identification is hampered by the multifactorial and heterogenic nature of this congenital anomaly. However, application of high-resolution molecular cytogenetic techniques to patients' DNA now enables detection of chromosomal aberrations in 30% of the patients. Furthermore, recent insights in rodent embryogenesis pointed to a specific disruption of the early mesenchymal structures in the primordial diaphragm of CDH-induced offspring. Together, these data allowed for the introduction of new hypotheses on CDH pathogenesis, although many issues remain to be resolved. In this review, we have combined these new insights and remaining questions on diaphragm pathogenesis with a concise overview of the clinical, embryological, and genetic data available.

Congenital diaphragmatic hernia

Congenital Diaphragmatic Hernia (CDH) is defined by the presence of an orifice in the diaphragm, more often left and posterolateral that permits the herniation of abdominal contents into the thorax. The lungs are hypoplastic and have abnormal vessels that cause respiratory insufficiency and persistent pulmonary hypertension with high mortality. About one third of cases have cardiovascular malformations and lesser proportions have skeletal, neural, genitourinary, gastrointestinal or other defects. CDH can be a component of Pallister-Killian, Fryns, Ghersoni-Baruch, WAGR, Denys-Drash, Brachman-De Lange, Donnai-Barrow or Wolf-Hirschhorn syndromes. Some chromosomal anomalies involve CDH as well. The incidence is < 5 in 10,000 live-births. The etiology is unknown although clinical, genetic and experimental evidence points to disturbances in the retinoid-signaling pathway during organogenesis. Antenatal diagnosis is often made and this allows prenatal management (open correction of the hernia in the past and reversible fetoscopic tracheal obstruction nowadays) that may be indicated in cases with severe lung hypoplasia and grim prognosis. Treatment after birth requires all the refinements of critical care including extracorporeal membrane oxygenation prior to surgical correction. The best hospital series report 80% survival but it remains around 50% in population-based studies. Chronic respiratory tract disease, neurodevelopmental problems, neurosensorial hearing loss and gastroesophageal reflux are common problems in survivors. Much more research on several aspects of this severe condition is warranted.

The central tendon defect: a rare problem, a novel technique

The rarest form of congenital diaphragmatic hernia involves a central tendon defect, which is often associated with a massive pericardial effusion. Very few of these have been reported, and they present unique challenges to the pediatric surgeon. We present a case report of our recent experience of this condition in a term neonate and the difficulties in diagnosing the condition. We also detail the first use of laparoscopy to close such a defect.

The embryology of the diaphragm

Despite the progress in prenatal diagnosis and intervention as well as postnatal therapeutic strategies, congenital diaphragmatic hernia (CDH) is still associated with a meaningful mortality because of the induced pulmonary hypoplasia. An essential key in understanding the pathogenesis of CDH is the underlying embryology, which has been neglected during the last decades. Likewise, the development of the normal diaphragm is still poorly understood. Obsolescent perceptions, mainly formed from histologic sections, are still propagated. In this review we present an atlas of scanning electron microscopy images that depict the normal and defective development of the diaphragm in the nitrofen rat model for CDH. Our findings suggest that the normal diaphragm mainly develops from the posthepatic mesenchymal plate. If the development of the posthepatic mesenchymal plate is impaired, a diaphragmatic defect occurs.

Abdominal hernias: Radiological features

Abdominal wall hernias are common diseases of the abdomen with a global incidence approximately 4%-5%. They are distinguished in external, diaphragmatic and internal hernias on the basis of their localisation. Groin hernias are the most common with a prevalence of 75%, followed by femoral (15%) and umbilical (8%). There is a higher prevalence in males (M:F, 8:1). Diagnosis is usually made on physical examination. However, clinical diagnosis may be difficult, especially in patients with obesity, pain or abdominal wall scarring. In these cases, abdominal imaging may be the first clue to the correct diagnosis and to confirm suspected complications. Different imaging modalities are used: conventional radiographs or barium studies, ultrasonography and Computed Tomography. Imaging modalities can aid in the differential diagnosis of palpable abdominal wall masses and can help to define hernial contents such as fatty tissue, bowel, other organs or fluid. This work focuses on the main radiological findings of abdominal herniations.

Vitamin A in reproduction and development

The requirement for vitamin A in reproduction was first recognized in the early 1900's, and its importance in the eyes of developing embryos was realized shortly after. A greater understanding of the large number of developmental processes that require vitamin A emerged first from nutritional deficiency studies in rat embryos, and later from genetic studies in mice. It is now generally believed that all-trans retinoic acid (RA) is the form of vitamin A that supports both male and female reproduction as well as embryonic development. This conclusion is based on the ability to reverse most reproductive and developmental blocks found in vitamin A deficiency induced either by nutritional or genetic means with RA, and the ability to recapitulate the majority of embryonic defects in retinoic acid receptor compound null mutants. The activity of the catabolic CYP26 enzymes in determining what tissues have access to RA has emerged as a key regulatory mechanism, and helps to explain why exogenous RA can rescue many vitamin A deficiency defects. In severely vitamin A-deficient (VAD) female rats, reproduction fails prior to implantation, whereas in VAD pregnant rats given small amounts of carotene or supported on limiting quantities of RA early in organogenesis, embryos form but show a collection of defects called the vitamin A deficiency syndrome or late vitamin A deficiency. Vitamin A is also essential for the maintenance of the male genital tract and spermatogenesis. Recent studies show that vitamin A participates in a signaling mechanism to initiate meiosis in the female gonad during embryogenesis, and in the male gonad postnatally. Both nutritional and genetic approaches are being used to elucidate the vitamin A-dependent pathways upon which these processes depend.

Protocolized management of infants with congenital diaphragmatic hernia: effect on survival

BACKGROUND/PURPOSE

In 2006, we introduced a new protocol for congenital diaphragmatic hernia (CDH) management featuring nitric oxide in the delivery room, gentle ventilation, lower criteria for extracorporeal membrane oxygenation (ECMO), and appropriately timed operative repair on ECMO. Our goals were to assess outcomes after institution of this protocol and to compare results with historical controls.

METHODS

Charts were reviewed of all newborns admitted to a large metropolitan children's hospital from 2002 to 2009 with a diagnosis of CDH. Data were recorded regarding delivery, ECMO, operative repair, length of stay, comorbidities/anomalies, complications, and survival. Postprotocol outcomes were compared to those from the preprotocol era and to data from the international CDH Registry.

RESULTS

Comparison of the protocolized group (n = 43) to the historical group (n = 51) revealed no significant differences in gestational age, birth weight, Apgar scores, or comorbidities. New treatment strategies substantially improved survival to discharge (67% preprotocol, 88% postprotocol; P = .015). Among ECMO patients, survival increased to 82% (20% preprotocol; P = .002).

CONCLUSIONS

Our new protocol significantly improved survival to discharge for newborns with CDH. Institution of such a protocol is valuable in improving outcomes for patients with CDH and merits consideration for widespread adoption.

Morgagni's diaphragmatic hernia mimicking a severe congenital heart disease in a newborn: a case report

Introduction

Morgagni's congenital diaphragmatic defect is a rare malformation, the diagnosis of which, as in our case report, may be problematic. To the best of our knowledge, this is the first report of this kind of hernia presenting with signs and symptoms of severe cardiac malformation.

Case presentation

We report the case of a three-month-old Caucasian baby boy, who presented with heart failure and severe pulmonary hypertension. Compression of the heart by a bowel loop in the chest led to an incorrect diagnosis of congenital heart disease.

Conclusions

Even in this era of highly sophisticated diagnostic tools, a simple radiograph can provide sufficient information for a precise, rapid diagnosis.

Prenatal detection of pulmonary hypoplasia in fetuses with congenital diaphragmatic hernia: a systematic review and meta-analysis of diagnostic studies

BACKGROUND

Fetuses with congenital diaphragmatic hernia (CDH) are at risk of death from pulmonary hypoplasia at birth.

OBJECTIVE

To determine the value of prenatal imaging parameters for predicting lethal pulmonary hypoplasia in fetuses with CDH.

SEARCH STRATEGY

Relevant papers were identified by searching MEDLINE (1966-2008), EMBASE (1988-2008) and the Cochrane Library (2008 issue 3).

SELECTION CRITERIA

Selected studies examined diagnostic tests for the prenatal prediction of lethal pulmonary hypoplasia in fetuses with CDH. The primary outcome measure was perinatal survival.

RESULTS

Twenty-one studies fulfilled the entry criteria, of which six examined entirely unique heterogeneous parameters and the remaining 15 examined lung-head ratios (LHR) and/or the presence of liver in the fetal thorax. The strongest association was that of LHR > or = 0.6 compared to <0.6 (OR: 17.02; 95% CI: 2.10-137.89), although more clinically relevant was that of LHR >1.0 (OR: 5.07; 95% CI: 2.94-8.74). The finding of liver in the fetal chest was a poor prognostic feature (survival OR: 0.32; 95% CI: 0.21-0.49).

CONCLUSION

In CDH, LHR and the presence of liver in the fetal thorax may be a useful predictive indicator of perinatal survival. Future usage of developing techniques needs careful evaluation prior to usage to guide therapy.

Nitrofen induces apoptosis independently of retinaldehyde dehydrogenase (RALDH) inhibition

BACKGROUND

Nitrofen is a diphenyl ether that induces congenital diaphragmatic hernia (CDH) in rodents. Its mechanism of action has been hypothesized as inhibition of the retinaldehyde dehydrogenase (RALDH) enzymes with consequent reduced retinoic acid signaling.

METHODS

To determine if nitrofen inhibits RALDH enzymes, a reporter gene construct containing a retinoic acid response-element (RARE) was transfected into HEK-293 cells and treated with varying concentrations of nitrofen in the presence of retinaldehyde (retinal). Cell death was characterized by caspace-cleavage microplate assays and terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assays. Ex vivo analyses of cell viability were characterized in fetal rat lung explants using Live/Dead staining. Cell proliferation and apoptosis were assessed using fluorescent immunohistochemistry with phosphorylated histone and activated caspase antibodies on explant tissues. Nile red staining was used to identify intracellular lipid droplets.

RESULTS

Nitrofen-induced dose-dependent declines in RARE-reporter gene expression. However, similar reductions were observed in control-reporter constructs suggesting that nitrofen compromised cell viability. These observed declines in cell viability resulted from increased cell death and were confirmed using two independent assays. Ex vivo analyses showed that mesenchymal cells were particularly susceptible to nitrofen-induced apoptosis while epithelial cell proliferation was dramatically reduced in fetal rat lung explants. Nitrofen treatment of these explants also showed profound lipid redistribution, primarily to phagocytes.

CONCLUSIONS

The observed declines in nitrofen-associated retinoic acid signaling appear to be independent of RALDH inhibition and likely result from nitrofen induced cell death/apoptosis. These results support a cellular apoptotic mechanism of CDH development, independent of RALDH inhibition.

Maternal periconceptional exposure to cigarette smoking and alcohol consumption and congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a major birth defect that occurs when abdominal organs herniate through a diaphragmatic opening into the thoracic cavity and is associated with high mortality (>50%). The etiology of CDH is not well understood.

METHODS

Using data from the National Birth Defects Prevention Study, we examined associations between CDH and maternal periconceptional exposure (1 month before through the third month of pregnancy) to cigarette smoking and alcohol. Interview reports of exposures were provided by mothers of CDH (n = 503) and unaffected control (n = 6703) infants delivered from October 1997 through December 2005. Any exposure (yes/no), as well as quantity (average number of cigarettes or drinks), type (active/passive smoking; beer, wine, distilled spirits), and duration (e.g., number of months exposed) were examined. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated for all CDH cases combined, selected subtypes (Bochdalek, Morgagni, not otherwise specified), and phenotypes (infants with/without additional major birth defects).

RESULTS

The aOR for any smoking was nonsignificantly elevated for all CDH cases combined. Odds of any smoking was significant for isolated Bochdalek CDH (aOR, 1.9; 95% CI, 1.2-3.0). The aORs associated with all measures of alcohol consumption were near unity for each CDH category examined. Stratification of smoking exposure by alcohol consumption and stratification of alcohol consumption by smoking exposure did not appreciably change the aORs.

CONCLUSIONS

These findings identified periconceptional smoking exposure as a potential risk factor for CDH. Future studies need to confirm our findings and explore possible pathways accounting for the teratogenic effect of smoking.

Outcomes of multigestational pregnancies affected by congenital diaphragmatic hernia

BACKGROUND/PURPOSE

The prognosis for multiple vs singleton pregnancies affected by congenital diaphragmatic hernia (CDH) is not known. To improve the counseling of families with multiple gestation pregnancies complicated by CDH, we examined outcomes of a consecutive series of CDH cases occurring in multiple gestation pregnancy referrals.

METHODS

Clinical characteristics and morbidity and mortality data were gathered for a consecutive series of infants with CDH from 16 multiple gestation pregnancies. Outcomes were compared to a cohort of 91 patients with CDH from singleton pregnancies. Multivariate regression was also used in an attempt to determine whether multiple gestation pregnancy was independently predictive of subsequent long-term adverse outcomes.

RESULTS

Four pregnancies were lost to follow-up, and 1 underwent selective reduction. Overall mortality for live-born multiple gestation fetuses affected by CDH was 30% and was 8% for unaffected siblings. No pregnancy was concordant. Clinical features were not different between the case series and control infants, except median gestational age at delivery, which was significantly lower for the multigestational infants (34 [range, 32-36] vs 38 [range, 28-41] weeks) (P = .02). Long-term morbidity was comparable between cases and controls.

CONCLUSIONS

In terms of mortality, outcomes of multigestational pregnancies affected by CDH are no worse than for CDH pregnancies in general. Long-term risk may depend more on CDH severity rather than the presence of multiple fetuses.

A maternally inherited chromosome 18q22.1 deletion in a male with late-presenting diaphragmatic hernia and microphthalmia-evaluation of DSEL as a candidate gene for the diaphragmatic defect

Using an Affymetrix GeneChip(R) Human Mapping 100K Set to study a patient with a late-presenting, right-sided diaphragmatic hernia and microphthalmia, we found a maternally inherited deletion that was 2.7 Mb in size at chromosome 18q22.1. Mapping of this deletion using fluorescence in situ hybridization revealed three deleted genes-CDH19, DSEL, and TXNDC10, and one gene that contained the deletion breakpoint, CCDC102B. We selected DSEL for further study in 125 patients with diaphragmatic hernias, as it is involved in the synthesis of decorin, a protein that is required for normal collagen formation and that is upregulated during myogenesis. We found p.Met14Ile in an unrelated patient with a late-presenting, anterior diaphragmatic hernia. In the murine diaphragm, Dsel was only weakly expressed at the time of diaphragm closure and its expression in C2C12 myoblast cells did not change significantly during myoblast differentiation, thus reducing the likelihood that the gene is involved in myogenesis of the diaphragm. Although it is possible that the 18q22.1 deletion and haploinsufficiency for DSEL contributed to the diaphragmatic defect in the patient, a definite role for DSEL and decorin in the formation of the collagen-containing, central tendon of the diaphragm has not yet been established.

Tracheomegaly: a complication of fetal endoscopic tracheal occlusion in the treatment of congenital diaphragmatic hernia

BACKGROUND

Fetal endoscopic tracheal occlusion (FETO) is a promising treatment for severe congenital diaphragmatic hernia, a condition that carries significant morbidity and mortality. It is hypothesised that balloon occlusion of the fetal trachea leads to an improvement in lung growth and development. The major documented complications of FETO to date are related to preterm delivery.

OBJECTIVE

To report a series of five infants who developed tracheomegaly following FETO.

MATERIALS AND METHODS

Review of all children referred with tracheomegaly to the paediatric intensive care and tracheal service at two referral centres.

RESULTS

Five neonates presented with features of respiratory distress shortly after birth and were subsequently found to have marked tracheomegaly. Two neonates had tracheomalacia in addition.

CONCLUSION

There are no previous reports in the literature describing tracheomalacia, or more specifically, tracheomegaly, as a consequence of FETO. We propose that the particularly compliant fetal airway is at risk of mechanical damage from in utero balloon occlusion. This observation of a new problem in this cohort suggests a thorough evaluation of the trachea should be performed in children who have had FETO in utero. It may be that balloon occlusion of the trachea earlier in utero (before 26 weeks' gestation) predisposes to this condition.

Preliminary observations of the use of high-frequency jet ventilation as rescue therapy in infants with congenital diaphragmatic hernia

BACKGROUND/PURPOSE

Congenital diaphragmatic hernia (CDH) is associated with mortality of 10% to 50%. Several investigators have reported outcomes from centers using high-frequency oscillatory ventilation in their management of CDH, but there are no recent reports on use of high-frequency jet ventilation.

METHODS

During the study period from January 2001 until August 2007, infants with CDH who were cared for at Duke University Medical Center received high-frequency jet ventilation as a rescue mode of high-frequency ventilation. We compared actual survival with predicted survival for infants treated only with conventional ventilation vs those rescued with high-frequency jet ventilation after failing conventional ventilation.

RESULTS

Survival for the 16 infants that received high-frequency jet ventilation was predicted to be 63%; actual survival was 75%. Survival for the 15 infants that received only conventional ventilation was predicted to be 83%; actual survival was 87%. We observed no significant survival benefit for high-frequency jet ventilation, 8.0% (95 confidence interval, -22.0% to 38.1%; P = .59).

CONCLUSIONS

Although our sample size was small, we conclude with consideration of the absolute results, the degree of illness of the infants, and the biologic plausibility for the intervention that high-frequency jet ventilation is an acceptable rescue ventilation mode for infants with CDH.

Early development of the primordial mammalian diaphragm and cellular mechanisms of nitrofen-induced congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a frequently occurring cause of neonatal respiratory distress and is associated with high mortality and long-term morbidity. Evidence from animal models suggests that CDH has its origins in the malformation of the pleuroperitoneal fold (PPF), a key structure in embryonic diaphragm formation. The aims of this study were to characterize the embryogenesis of the PPF in rats and humans, and to determine the potential mechanism that leads to abnormal PPF development in the nitrofen model of CDH. Analysis of rat embryos, and archived human embryo sections, allowed the timeframe of PPF formation to be determined for both species, thus delineating a critical period of diaphragm development in relation to CDH. Experiments on nitrofen-exposed NIH 3T3 cells in vitro led us to hypothesize that nitrofen might cause diaphragmatic hernia in vivo by two possible mechanisms: through decreased cell proliferation or by inducing apoptosis. Data from nitrofen-exposed rat embryos indicates that the primary mechanism of nitrofen teratogenesis in the PPF is through decreased cell proliferation. This study provides novel insight into the embryogenesis of the PPF in rats and humans, and it indicates that impaired cell proliferation might contribute to abnormal diaphragm development in the nitrofen model of CDH.

Downregulation of insulin-like growth factor binding protein 3 and 5 in nitrofen-induced pulmonary hypoplasia

PURPOSE

The high mortality in congenital diaphragmatic hernia (CDH) is mainly attributed to pulmonary hypoplasia. Recent studies suggest that retinoid signaling pathway (RSP) is inhibited in the nitrofen-induced hypoplastic lung. The insulin-like growth factor (IGF) system plays a crucial role in fetal lung development by interaction of IGFBP-3 and IGFBP-5 with RSP. We hypothesized that pulmonary IGFBP-3 and IGFBP-5 gene expression levels are downregulated in the nitrofen-induced pulmonary hypoplasia.

METHODS

Pregnant rats were exposed to either olive oil or 100 mg nitrofen on day 9.5 (D9.5) of gestation. Fetal lungs were harvested on D18 and D21 and divided into control and nitrofen groups. IGFBP-3 and IGFBP-5 pulmonary gene and protein expression were determined using real-time RT-PCR and immunohistochemistry.

RESULTS

Relative levels of IGFBP-3 mRNA were significantly decreased in the nitrofen group (8.00 +/- 14.44) in D21 compared to controls (14.81 +/- 16.11; p < 0.05). Expression levels of IGFBP-5 mRNA were also significantly decreased in nitrofen group (10.66 +/- 4.83) on D18 compared to controls (17.92 +/- 4.77). Immunohistochemistry showed decreased IGFBP-3 expression on D21 and decreased IGFBP-5 immunoreactivity on D18 in hypoplastic lungs compared to controls.

CONCLUSION

Downregulation of IGFBP-3 and IGFBP-5 gene expression may cause pulmonary hypoplasia in the nitrofen-induced CDH model by interfering with retinoid signaling pathway.

CONTEMPORARY NEONATAL INTENSIVE CARE MANAGEMENT IN CONGENITAL DIAPHRAGMATIC HERNIA: DOES THIS OBVIATE THE NEED FOR FETAL THERAPY?

The management of congenital diaphragmatic hernia (CDH) in the newborn infant has changed radically since the first successful outcomes were reported 60 years ago. Then it seemed a surgical problem with a surgical solution – do an operation, remove the intestines and solid viscera from the thoracic cavity, repair the defect and allow the lung to expand. CDH in that era was regarded as the quintessential neonatal surgical emergency. The expectation was that urgent surgery would result in improvement in lung function and oxygenation. That approach persisted up to the 1980s when it was realized that the problem was far more complex and involved both an abnormal pulmonary vascular bed as well as pulmonary hypoplasia. The use of systemically delivered pulmonary vasodilator therapy, principally tolazoline, became a focus of interest in the 1980s with small case reports and case series suggesting improved survival. In the 1990s, based on studies that showed worsening thoracic compliance and gas exchange following surgical repair, deferred surgery and pre-operative stabilization became the standard of care. At the same time extracorporeal membrane oxygenation (ECMO) was increasingly used either as part of pre-operative stabilization or as a rescue therapy after repair. Other centres chose to use high frequency oscillatory ventilation (HFOV). Despite all these innovations the survival in live born infants with CDH did not improve to more than 50% in large series published from high volume centres. However, in the past 10 years there has been an appreciable improvement in survival to the extent that many centres are now reporting survival rates of greater than 80%. Probably the biggest impact on this improvement has been the recognition of the role that ventilation induced lung injury plays in mortality and the need for ECMO rescue. This has ushered in an era of a lung protective or “gentle ventilation” strategy which has been widely adopted as a standard approach. While there have been these radical changes in postnatal management attempts have been made to improve outcome with prenatal interventions, starting with prenatal repair, which was abandoned because of preterm labour. More recently there has been increasing experience in the use of balloon occlusion of the trachea as a prenatal intervention strategy with patients being selected based on prenatal predictors of poor outcome. This approach can only be justified if those predictors can be validated and the outcomes (death or serious long term morbidity) can be shown to be better than those currently achievable, namely 80% survival in high volume CDH centres rather than the 50–60% survival frequently quoted in historical papers.

Delivery room management of the newborn

Neonatal resuscitation is an attempt to facilitate the dynamic transition from fetal to neonatal physiology. This article outlines the current practices in delivery room management of the neonate. Developments in cardiopulmonary resuscitation techniques for term and preterm infants and advances in the areas of cerebral resuscitation and thermoregulation are reviewed. Resuscitation in special circumstances (such as the presence of congenital anomalies) are also covered. The importance of communication with other members of the health care team and the family is discussed. Finally, future trends in neonatal resuscitation are explored.

Understanding abnormal retinoid signaling as a causative mechanism in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a frequently occurring source of severe neonatal respiratory distress. It has been hypothesized that abnormal retinoid signaling contributes to the etiology of this developmental anomaly. Here, we use rodent models toward specifically understanding the role of retinoid signaling in the developing diaphragm and how its perturbation is a common mechanism in drug-induced CDH. This includes monitoring of retinoic acid (RA) response element (RARE) activation with RARE-lacZ mice, RA supplementation studies, systematic analyses of the expression profile of key elements in the RA signaling pathway within the developing diaphragm, and the in utero delivery of a RA receptor (RAR) antagonist. These data demonstrate the timing of RARE perturbation by CDH-inducing teratogens and the efficacy of RA supplementation. Furthermore, a detailed profile of retinoid binding proteins, synthetic enzymes, and retinoid receptors within primordial diaphragm cells was obtained. The expression profile of RAR-alpha was particularly striking in regard to its overlap with the regions of primordial diaphragm affected in multiple CDH models. Blocking of RAR signaling with the pan-RAR antagonist BMS493 induced a very high degree of CDH, with a marked left-right sidedness that depended on the timing of drug delivery. Collectively, these data demonstrate that retinoid signaling is essential for normal diaphragm development, providing further support to the hypothesis that abnormalities related to the retinoid signaling pathway cause diaphragmatic defects. This study also yielded a novel experimental model that should prove particularly useful for further studies of CDH.

Sequence variants in the HLX gene at chromosome 1q41-1q42 in patients with diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common birth defect for which few causative genes have been identified. Several candidate regions containing genes necessary for normal diaphragm development have been identified, including a 4-5 Mb deleted region at chromosome 1q41-1q42 from which the causative gene(s) has/have not been cloned. We selected the HLX gene from this interval as a candidate gene for CDH, as the Hlx homozygous null mouse has been reported to have diaphragmatic defects and the gene was described as being expressed in the murine diaphragm. We re-sequenced HLX in 119 CDH patients and identified four novel single nucleotide substitutions that predict amino acid changes: p.S12F, p.S18L, p.D173Y and p.A235V. These sequence alterations were all present in patients with isolated CDH, although patients with both isolated CHD and CDH with additional anomalies were studied. The single-nucleotide substitutions were absent in more than 186 control chromosomes. In-situ hybridization studies confirmed expression of Hlx in the developing murine diaphragm at the site of the junction of the diaphragm and the liver. Although functional studies to determine if these novel sequence variants altered the inductive activity of Hlx on the alpha-smooth muscle actin and SM22alpha promoters showed no significant differences between the variants and wild-type Hlx, sequence variants in HLX may still be relevant in the pathogenesis of CDH in combination with additional genetic and environmental factors.

Congenital diaphragmatic hernia: an overview of the etiology and current management

AIM

To review provide an overview of the etiology and current strategies in the management of congenital diaphragmatic hernia (CDH).

METHODS

We did a comprehensive review of research trends, evidence based studies and epidemiologic studies.

RESULTS

CDH is a life-threatening pathology in infants, and a major cause of death due to the pulmonary hypoplasia and pulmonary hypertension. There is much research related to elucidating the etiology of CDH and developing management strategies to improve the outcomes in these infants.

CONCLUSION

An early diagnosis with increased understanding of this disease is a crucial factor for a timely approach to managing the critically ill infant, and to offer the potential for improved outcomes and substantial reductions in morbidity.

Nutrient intakes in women and congenital diaphragmatic hernia in their offspring

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a severe birth defect where there is an opening in the diaphragm through which a portion of the abdominal contents protrudes into the thoracic cavity. The etiologies of CDH remain unknown, although experimental animal data suggest dietary factors might play a role. This study examined whether maternal nutrient intakes were associated with delivering infants with CDH.

METHODS

We analyzed infants with isolated CDH who were born from 1997 to 2003 and recruited into the National Birth Defects Prevention Study (NBDPS), a multisite, population-based case-control study. Exposure data were obtained from telephone interviews, which were completed within 24 months after delivery, and were available for 377 case mothers and 5,008 control mothers. A food frequency questionnaire was used to derive nutrient intakes during the year before pregnancy.

RESULTS

A crude OR of 0.6 (95% CI: 0.3-1.0) was observed for higher intake of choline. Elevated ORs (1.4 to 1.7) were found for lower intakes of choline, cysteine, methionine, and protein. Among women who took vitamin supplements, higher intakes of B vitamins (i.e., folate, vitamin B1, B2, B6, and B12), minerals (i.e., calcium, iron, magnesium, and zinc), and vitamin E were inversely associated with CDH (ORs from 0.7-0.3). Moreover, among women who did not take vitamin supplements, lower intakes of calcium, retinol, selenium, vitamin B12, and vitamin E had positive associations with CDH (ORs from 1.4 to 2.1).

CONCLUSIONS

Our observations contribute to a limited body of evidence suggesting a woman's periconceptional diet might be associated with CDH in her offspring.

Genetic aspects of human congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common major malformation affecting 1/3000-1/4000 births, which continues to be associated with significant perinatal mortality. Much current research is focused on elucidating the genetics and pathophysiology contributing to CDH to develop more effective therapies. The latest data suggest that many cases of CDH are genetically determined and also indicate that CDH is etiologically heterogeneous. The present review will provide a brief summary of diaphragm development and model organism work most relevant to human CDH and will primarily describe important human phenotypes associated with CDH and also provide recommendations for diagnostic evaluation of a fetus or infant with CDH.

Congenital diaphragmatic hernia and retinoids: searching for an etiology

Congenital diaphragmatic hernia (CDH) is a major life-threatening cause of respiratory failure in the newborn. Recent data reveal the role of a retinoid-signaling pathway disruption in the pathogenesis of CDH. We describe the epidemiology and pathophysiology of human CDH, the metabolism of retinoids and the implications of retinoids in the development of the diaphragm and lung. Finally, we describe the existing evidence of a disruption of the retinoid-signaling pathway in CDH.

Main bronchus occlusion for treatment of congenital diaphragmatic hernia in fetal lambs

PURPOSE

The present study investigates a new surgical approach in the treatment of left diaphragmatic hernia in fetal sheep. We postulated that unlike tracheal occlusion where both lungs are occluded, selective left main bronchus occlusion (LMBO) would accelerate growth of only the left lung, reduce left visceral herniation, and recover space in the both thoraces necessary for lung development.

METHODS

Left-sided congenital diaphragmatic hernia (CDH) was surgically created in 8 fetal lambs at approximately 65 days of gestation; in 4 of these animals, LMBO was performed at approximately 118 days. Four sham-operated animals served as controls. Lambs were delivered by hysterotomy at 137 days. We measured lung-to-body weight ratios, alveolar surface area, septal wall thickness, and AE2 cell density in the left and right lungs.

RESULTS

Left main bronchus occlusion increased (P < .05) left lung growth causing severe right mediastinal shift but failed to reduce herniated abdominal viscera in 3 of 4 lambs. Wet lung-to-body weight ratio in LMBO group was similar to that of the control group; however, this was achieved by overgrowth of left lung, whereas the right wet lung-to-body weight ratio remained low. In the LMBO group, right lung AE2 cell density was higher than that of control group and not different to that of the CDH group.

CONCLUSIONS

Left main bronchus occlusion failed to restore normal pulmonary development in CDH.

Congenital diaphragmatic hernia in CHARGE syndrome

Congenital diaphragmatic hernia (CDH) has been rarely described in CHARGE syndrome. We report a patient affected by CHARGE syndrome presenting with a right-sided Bochdalek-type diaphragmatic hernia, and collect the pertinent literature. Furthermore, we review the embryogenesis of the diaphragm and the pathogenesis of CDH to highlight if this malformation could be explained by a developmental anomaly of CHARGE. On the basis of our study, we suggest that patients affected by CDH, facial asymmetry and cardiovascular or urogenital malformations, should be actively screened for CHARGE syndrome findings.

Gene expression in the developing diaphragm: significance for congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a frequently occurring birth defect and a source of potentially fatal neonatal respiratory distress. Recently, through the application of detailed karyotyping methods, several CDH-critical regions within the human genome have been identified. These regions typically contain several genes. Here we focused on genes from 15q26, the best-characterized CDH-critical region, as well as FOG2 and GATA4, genes singled out from CDH-critical regions at 8q22-8q23 and 8p23.1, respectively. We tested the hypothesis that these putative CDH-related genes are expressed within the developing diaphragm at the time of the hypothesized initial defect. Our results show that 15q26 contains a cluster of genes that are expressed in the developing rodent diaphragm, consistent with an association between deletions in this region and CDH. We then examined the protein expression pattern of positively identified genes within the developing diaphragm. Two major themes emerged. First, those factors strongly associated with CDH are expressed only in the nonmuscular, mesenchymal component of the diaphragm, supporting the hypothesis that CDH has its origins in a mesenchymal defect. Second, these factors are all coexpressed in the same cells. This suggests that cases of CDH with unique genetic etiology may lead to a common defect in these cells and supports the hypothesis that these factors may be members of a common pathway. This study is the first to provide a detailed examination of how genes associated with CDH are expressed in the developing diaphragm and provides an important foundation for understanding how the deletion of specific genes may contribute to abnormal diaphragm formation.

Diaphragmatic defects and limb deficiencies - taking sides

Diaphragmatic defects and limb deficiencies usually occur as independent anomalies, as a polytopic field defect (in which ipsilateral anomalies might be expected) or as wider pattern of defects, potentially involving disturbance of laterality or the midline (in which bilateral or contralateral defects would occur). Data on cases from previous studies and/or the literature were used to determine whether there is an association between the sides involved in the defects. The 88 adequately described cases identified included 20 with de Lange syndrome, seven with Poland anomaly, four with trisomy 18, 52 with other patterns of multiple malformations and five with diaphragmatic and limb defects alone. Evaluation of the position of the limb (left, right, bilateral) and the diaphragmatic defects (left, right, bilateral) did not show significant association in patterns of sidedness (P = 0.48). In 56% of cases, the limb deficiencies were bilateral. Among the 32 unilateral cases, 19 (59%) were ipsilateral (15 left; 4 right) and 13(41%) were contralateral (P = 0.38). Eleven of the 13 contralateral cases had left sided diaphragmatic defects and right sided limb deficiency; four had de Lange syndrome and nine had other patterns of multiple anomalies. Only cases with Poland anomaly or otherwise isolated defects showed a trend towards ipsilateral defects. Most cases with multiple congenital anomalies, had limbs defects on both the right and left (57%) or both sides of the diaphragm were affected (an additional 10%), indicating a widespread dysmorphogenetic process rather than a more restricted field defect. In other cases, defects were bilateral or, if unilateral, reflected the propensities for diaphragmatic defects to more often involve the left side, and limb defects, the right.

Paradoxical movement of abdominal contents: a real-time sonographic finding indicating a congenital diaphragmatic hernia

OBJECTIVE

A congenital diaphragmatic hernia (CDH) is the most common intrathoracic extracardiac congenital anomaly, and it is associated with high mortality and other fetal abnormalities. Early diagnosis is essential for delivery planning and possible intervention. However, the in utero diagnosis of CDHs by sonography can be challenging. We report the utility of paradoxical movement of the intra-abdominal contents in identifying CDHs.

METHODS

Two fetal cases were identified: 1 referred with a suspected CDH and the other with a mediastinal shift and a suspected congenital cystic adenomatoid malformation (CCAM). Real-time sonography was performed in both fetuses with attention on movement of the intra-abdominal contents during fetal breathing, particularly during inspiration.

RESULTS

Real-time sonography in both fetuses showed paradoxical movement of the abdominal contents during fetal inspiration. In the case with the presumptive diagnosis of a CCAM, the paradoxical motion was essential in changing the diagnosis from a CCAM to a CDH.

CONCLUSIONS

Paradoxical movement of the abdominal contents can be used in addition to the traditional sonographic signs in diagnosing CDHs.

Linking animal models to human congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a major life-threatening malformation, occurring in approximately 1 in 3,000 live births. Over the years, different animal models have been used to gain insight into the etiology of this complex congenital anomaly and to develop treatment strategies. However, to date the pathogenic mechanism is still not understood, and treatment remains difficult because of the associated pulmonary hypoplasia and pulmonary hypertension.

METHODS

In this review, data available from several animal models will be discussed. The retinoic acid signaling pathway (RA pathway, retinoid pathway) will be addressed as a developmental pathway that is potentially disrupted in the pathogenesis of CDH. Furthermore, genetic factors involved in diaphragm and lung development will be discussed.

CONCLUSIONS

With this review article, we aim to provide a concise overview of the current most important experimental genetic data available in the field of CDH.

Congenital diaphragmatic hernia, etiology and management, a 10-year analysis of a single center

OBJECTIVE

To analyze congenital diaphragmatic hernia (CDH) during a 10-year period at the University of Kiel, from 1995 through 2004, in order to develop a strategy to improve prenatal diagnosis, to be able to consider endoscopical treatment for selected cases and to assess the current postnatal treatment strategies.

METHODS

Data were obtained from the fetal medicine ultrasound department, from the birth registry, from the postmortem registry, from the neonatal intensive care unit, from pediatric surgery and from the genetic database. Data were subselected for chromosomes, genetic syndromes, for isolated CDH and for associated anomalies, the lung to head ratio and lung volumes were assessed. Data were analyzed respectively for gestation at diagnosis, the type of CDH, the perinatal management and the postnatal outcome.

RESULTS

There were 29 cases of CDH, in 10/29 (34%) the parents requested termination of pregnancy of which two had already died during pregnancy, 12/19 (63%) survived, which was defined as discharge from the neonatal intensive care unit, seven newborns 7/19 (37%) died in the hospital, 5 of these 5/7 (71%) were delivered in Kiel. A prenatal diagnosis was performed in 16/29 (55%), 1/16 (6%), 7/16 (43%) and 8/16 (50%) in the 1st, 2nd and 3rd trimester, respectively; in 10/29 (34%) diagnosis was performed postpartum, in 3/29 (10%) the diagnosis was performed at autopsy following termination of pregnancy. When the liver was in the abdomen, 9/10 (90%) of the children survived, compared to only 3/8 (43%) when the liver was located in the thorax. A lung to head ratio of 0.81 at 24 weeks resulted in death due to pulmonary hypoplasia.

CONCLUSIONS

The overall survival in CDH is around 50%, antenatal endoscopical therapy may only be considered, if the diagnosis is performed in the early second trimester, and selection criteria such as the lung to head ratio, associated defects and the chromosomal status can be applied.

Single gene disorders associated with congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common birth defect with a high pre- and postnatal mortality. Although the majority of diaphragmatic hernias occur as isolated malformations, additional major and minor anomalies are common and are present in more than 40% of patients. There are compelling data for the importance of genetic factors in the etiology of CDH, but the pathogenesis and the causative genes for CDH in humans remain elusive. There are more than 70 syndromes in which diaphragmatic hernias have been described, and several of these syndromes are single gene disorders for which the gene is known. One method for identifying the causative genes in isolated CDH is to study syndromes with known genes in which CDH is a recognized feature, with the rationale that those genes have a role in diaphragm development. This review discusses the syndromes that are most commonly associated with CDH, with greater attention towards syndromes in which the causative genes have been identified, including Simpson-Golabi-Behmel syndrome, Denys-Drash syndrome, spondylocostal dysostosis, craniofrontonasal syndrome, Cornelia de Lange syndrome and Marfan syndrome.

Candidate genes for congenital diaphragmatic hernia from animal models: sequencing of FOG2 and PDGFRα reveals rare variants in diaphragmatic hernia patients

Congenital diaphragmatic hernia (CDH) is a common, life threatening birth defect. Although there is strong evidence implicating genetic factors in its pathogenesis, few causative genes have been identified, and in isolated CDH, only one de novo, nonsense mutation has been reported in FOG2 in a female with posterior diaphragmatic eventration. We report here that the homozygous null mouse for the Pdgfralpha gene has posterolateral diaphragmatic defects and thus is a model for human CDH. We hypothesized that mutations in this gene could cause human CDH. We sequenced PDGFRalpha and FOG2 in 96 patients with CDH, of which 53 had isolated CDH (55.2%), 36 had CDH and additional anomalies (37.5%), and 7 had CDH and known chromosome aberrations (7.3%). For FOG2, we identified novel sequence alterations predicting p.M703L and p.T843A in two patients with isolated CDH that were absent in 526 and 564 control chromosomes respectively. These altered amino acids were highly conserved. However, due to the lack of available parental DNA samples we were not able to determine if the sequence alterations were de novo. For PDGFRalpha, we found a single variant predicting p.L967V in a patient with CDH and multiple anomalies that was absent in 768 control chromosomes. This patient also had one cell with trisomy 15 on skin fibroblast culture, a finding of uncertain significance. Although our study identified sequence variants in FOG2 and PDGFRalpha, we have not definitively established the variants as mutations and we found no evidence that CDH commonly results from mutations in these genes.