Necrotizing enterocolitis in the full-term neonate

Copious amount of bloody stool in a newborn shortly after birth

Melena neonatorum is not uncommon; it presents as bloody stool in newborns and is caused by ingestion of maternal blood. This case presents an infant who had multiple episodes of copious amount of blood in his stool starting at 10 min of life, which raised multiple concerns requiring further investigation. The alkali denaturation test confirmed that the blood was maternal; however, due to the amount of bloody stool and the time required for the alkali denaturation test to result, further workups such as abdominal radiograph and hemoglobin/hematocrit were completed to ensure nothing was overlooked. Our infant remained clinically stable under the newborn nursery care, and did not require a higher level of care. He was discharged with his mother at 52 Hours of Life with a follow-up appointment the next day with the Primary Care Physician.

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

OBJECTIVE

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

CONCLUSION

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

Bloody Stools in a 3-Day-Old Term Infant

A 3-day-old term, male infant presented to the emergency department for evaluation of bloody stools. The infant was born after an uncomplicated pregnancy followed by a normal spontaneous vaginal delivery. The mother was group B Streptococcus colonized, and received antenatal penicillin prophylaxis. The infant received routine delivery room care, and was given ophthalmic erythromycin and intramuscular vitamin K. Circumcision was performed without bleeding and he was discharged from the newborn nursery and the hospital after 48 hours. On the day of presentation, he had streaky bright red blood in 4 consecutive stools. After discussion with the infant's pediatrician, the parents took him to the emergency department. The infant was afebrile, nursing well without emesis, and had made ∼10 wet diapers that day. The physical examination revealed a fussy infant with mild tachycardia, tachypnea, and scleral icterus. The complete blood count was unremarkable. Serum total bilirubin was 11.9 mg/dL, sodium 156 mmol/L, chloride 120 mmol/L, potassium 4.7 mmol/L, and bicarbonate 16 mmol/L. International normalized ratio was prolonged at 2.7, prothrombin time 26.6 seconds, partial thromboplastin time 38.9 seconds. The stool was hemeoccult positive. An obstructive radiograph series of the abdomen showed a nonobstructed gas pattern. Official radiology interpretation the following day reported possible pneumatosis intestinalis in the left and right colon. Our multidisciplinary panel will discuss the assessment of bloody stools in the term newborn, evaluation of electrolyte abnormalities, the diagnosis, and patient management.

Diagnostic imaging features of necrotizing enterocolitis: a narrative review

Necrotizing enterocolitis (NEC) is an inflammatory process, characterized by intestinal necrosis of variable extension, leading to perforation, generalized peritonitis and death. The classical pathogenetic theory focuses on mucosal damage related to a stress induced intestinal ischemia leading to mucosal injury and bacterial colonization of the wall. A more recent hypothesis emphasizes the role of immaturity of gastrointestinal and immune system, particularly of the premature, responsible of bowel wall vulnerability and suffering. NEC is the most common gastrointestinal emergency in the newborn, with a higher incidence in the preterm; improvement of neonatal resuscitation techniques enables the survival of premature of very low birth weight (VLBW) with prolongation of hospital stay for perinatal and neonatal care and a higher risk of NEC. Clinical presentation of NEC in newborn ranges from mild forms with moderate gastrointestinal tract disorder and that can heal spontaneously, to very serious forms with fulminant course characterized by perforation, peritonitis, sepsis, disseminated intravascular coagulation (DIC) and shock. Imaging modality in the diagnosis of NEC is historically represented by the plain-film abdominal radiographs which can be performed every 6 hours because of the rapid evolution that may occur in the patient's clinical condition. However ultrasound (US), in recent years, is playing an increasingly important role in the evaluation of early stages of the disease as it provides images in real time of the abdominal structures being able to assess the presence and validity of peristalsis of the bowel loops, detect the thickness of the intestinal wall and the presence of minimal amounts of fluid in the peritoneal cavity. In this paper we review the pathogenesis, clinical presentation and imaging of NEC with a particular attention to the emergent role of US in the diagnosis of the disease.

Cluster of late preterm and term neonates with necrotizing enterocolitis symptomatology: descriptive and case-control study

OBJECTIVE

To investigate a necrotizing enterocolitis (NEC) cluster of late preterm and term neonates (gestational age ≥34 weeks).

METHODS

We conducted a descriptive and a case-control study. Medical records of neonates with modified Bell stage ≥ IB NEC and matched controls were reviewed, in addition to microbiological and environmental investigation. Study variables included maternal/delivery and neonatal factors, medications, procedures and feeding practices. Univariable/multivariable logistic regression analyses were performed for all and for stage ≥ II cases.

RESULTS

Out of 1841 late preterm and term neonates, 10 stage IB and 10 stage ≥ II [mean(SD) birthweight 2529.3 (493.04) g, gestational age 36.96 (1.48) weeks] presented with NEC symptomatology at mean 4.6 (range 2-8) days. Nearly all (19/20) resulted from high-risk pregnancies and received postpartum intermediate care. All were exclusively or partly formula fed. Most (14/20) were born by cesarean delivery. Eight underwent surgery, with no fatality. Intermediate care (p = 0.006), transient tachypnea (p = 0.049), not receiving breast milk (p = 0.019) and in addition intrauterine growth restriction (IUGR) (p = 0.017) for stage ≥ II cases were independently associated with NEC.

CONCLUSIONS

Late preterm and term neonates in need of intermediate care, with IUGR and transient tachypnea were susceptible to NEC; feeding with breast milk was an important protective factor.

Necrotizing enterocolitis: controversies and challenges

Necrotizing enterocolitis is a devastating intestinal disease that affects ~5% of preterm neonates. Despite advancements in neonatal care, mortality remains high (30–50%) and controversy still persists with regards to the most appropriate management of neonates with necrotizing enterocolitis. Herein, we review some controversial aspects regarding the epidemiology, imaging, medical and surgical management of necrotizing enterocolitis and we describe new emerging strategies for prevention and treatment.

Neonatal colonic perforation

Neonatal colonic perforation is a rarely seen condition. Plain abdominal radiography of a 28-hour newborn consulted for vomiting and bloody stool revealed the presence of subdiaphragmatic free air, which necessitated surgical exploration. Transverse colonic perforation was detected during the exploration, and subsequently, a colostomy and appendectomy were performed. The postoperative follow-up period was uneventful. Necrotizing enterocolitis, Hirschsprung disease, and mechanical obstruction are some of the causes of colonic perforation during the neonatal period. Herein, we have shared a case of colonic perforation in an asphyctic newborn delivered after prolonged labor.

Late onset of necrotizing enterocolitis in the full-term infant is associated with increased mortality: results from a two-center analysis

PURPOSE

The effect of timing of onset of necrotizing enterocolitis (NEC) on outcomes has not been determined for the full-term infant. In this study we aimed to characterize the full-term NEC population and to evaluate onset of NEC.

METHODS

We performed a two-center retrospective review of all full-term infants (≥ 37weeks) with a diagnosis of NEC between 1990 and 2012. Patients were identified by ICD-9 and age. Early onset for NEC was ≤7days and late onset after 7days of life. Demographics, comorbidities, maternal factors, clinical factors, surgical intervention, complications, and mortality were evaluated. Wilcoxon's test was performed on continuous variables and Fisher's exact test on categorical data. A p-value<0.05 was considered significant. Univariate outcomes with a p-value<0.1 were selected for multivariable analysis.

RESULTS

Thirty-nine patients (24 boys, 15 girls) with median EGA of 39weeks were identified. Overall mortality was 18%. Univariate predictors of mortality included congenital heart disease and placement of an umbilical artery (UA) catheter. Multivariate analysis revealed late onset of NEC to be an independent predictor of mortality (OR 90.8, 95% CI 2.6-3121).

CONCLUSION

Full-term infants who develop NEC after 7days of life, have congenital heart disease, and/or need UA catheterization have increased mortality.

Long term healthcare costs of infants who survived neonatal necrotizing enterocolitis: a retrospective longitudinal study among infants enrolled in Texas Medicaid

BACKGROUND

Infants who survive advanced necrotizing enterocolitis (NEC) at the time of birth are at increased risk of having poor long term physiological and neurodevelopmental growth. The economic implications of the long term morbidity in these children have not been studied to date. This paper compares the long term healthcare costs beyond the initial hospitalization period incurred by medical and surgical NEC survivors with that of matched controls without a diagnosis of NEC during birth hospitalization.

METHODS

The longitudinal healthcare utilization claim files of infants born between January 2002 and December 2003 and enrolled in the Texas Medicaid fee-for-service program were used for this research. Propensity scoring was used to match infants diagnosed with NEC during birth hospitalization to infants without a diagnosis of NEC on the basis of gender, race, prematurity, extremely low birth weight status and presence of any major birth defects. The Medicaid paid all-inclusive healthcare costs for the period from 6 months to 3 years of age among children in the medical NEC, surgical NEC and matched control groups were evaluated descriptively, and in a generalized linear regression framework in order to model the impact of NEC over time and by birth weight.

RESULTS

Two hundred fifty NEC survivors (73 with surgical NEC) and 2,909 matched controls were available for follow-up. Medical NEC infants incurred significantly higher healthcare costs than matched controls between 6-12 months of age (mean incremental cost = US$ 5,112 per infant). No significant difference in healthcare costs between medical NEC infants and matched controls was seen after 12 months. Surgical NEC survivors incurred healthcare costs that were consistently higher than that of matched controls through 36 months of age. The mean incremental healthcare costs of surgical NEC infants compared to matched controls between 6-12, 12-24 and 24-36 months of age were US$ 18,274, 14,067 (p < 0.01) and 8,501 (p = 0.06) per infant per six month period, respectively. These incremental costs were found to vary between sub-groups of infants born with birth weight < 1,000g versus ≥ 1,000g (p < 0.05).

CONCLUSIONS

The all-inclusive healthcare costs of surgical NEC survivors continued to be substantially higher than that of matched controls through the early childhood development period. These results can have important treatment and policy implications. Further research in this topic is needed.

Necrotizing enterocolitis in term infants

This article is an overview of NEC in term neonates and also summarizes data from 52 cases within Intermountain Healthcare during the last 11 years. In all 52, NEC occurred among neonates already admitted to a neonatal intensive care unit for some other reason; thus, NEC invariably developed as a complication of treatment, not as a primary diagnosis. The authors speculate that the incidence of term NEC can be reduced by identifying neonatal intensive care unit patients at risk for NEC and applying appropriate-volume human milk feeding programs for these patients.

Human isolates of Cronobacter sakazakii bind efficiently to intestinal epithelial cells in vitro to induce monolayer permeability and apoptosis

BACKGROUND

Cronobacter sakazakii (CS) is an emerging opportunistic pathogen that causes life-threatening infections in infants. This pathogen has been implicated in the outbreaks of necrotizing enterocolitis (NEC) with associated rates of high mortality and morbidity. In this study, we compared the abilities of CS strains isolated from human and environmental sources to bind to intestinal epithelial cells and trigger apoptosis.

MATERIALS AND METHODS

CS strains were isolated from human and environmental sources and their abilities to bind to intestinal epithelial cells were determined. Monolayer permeability was determined by transepithelial electrical resistance (TEER) and horseradish peroxidase (HRP) leakage. Apoptosis was examined by ApoTag and AnnexinV-7AAD staining. PKC activation was evaluated by non-radioactive PepTag assay.

RESULTS

Human isolates of CS bind to rat and human enterocytes more efficiently than environmental strains. Additionally, these strains induced increased enterocyte monolayer permeability as indicated by a decrease in TEER and an increase in transcellular leakage of exogenously added HRP. Human isolates also caused tight junction disruption and significant apoptosis of enterocytes compared with environmental strains due to increased production of inducible nitric oxide. We also observed that human CS isolates caused 2-fold increase in the activation of phosphokinase C (PKC) than environmental strains. Blocking the PKC activity in enterocytes by an inhibitor, Gö 6983, suppressed CS-mediated tight junction disruption, monolayer permeability, and apoptosis of the cells.

CONCLUSION

These results suggest that human isolates of CS more efficiently bind to and cause damage to intestinal epithelial cells compared with environmental strains.

Probiotics in the prevention of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a common gastrointestinal inflammatory necrosis affecting almost exclusively premature infants usually after oral nutrition has been started, for example, 10 day plus postpartum. Although the pathogenesis is incompletely understood, major risk factors include prematurity and incomplete bacterial colonization. Evidence has been shown that the premature infant because of rapid passage through the birth canal or because of delivery by cesarean section has an inadequate initial ingestion of maternal colonic and vaginal flora and therefore, an inadequate initial colonization with less diversity of bacteria phylla and fewer species of bacteria in the microbiota. As a result, they are more susceptible to environmental pathogens. In addition, prematures have immature intestinal defenses (glycocalyx, tight junctions, innate immune response, etc.) resulting in excessive inflammation in response to luminal stimuli. Recently, we reported that genes mediating the innate inflammatory immune response are developmentally expressed with an increase in toll-like receptors, signaling molecules and transgenic factors and decreased negative regulators of inflammation, which undoubtedly contribute to an excessive inflammatory response. Several clinical studies have suggested that the use of probiotics and ingestion of expressed maternal breast milk containing probiotics can help to stabilize colonization and to reduce the incidence and severity of NEC when given to premature infants at risk. Meta-analyses of multiple small studies strongly suggest a protective effect in the use of probiotics. A multicenter study in Taiwan suggests that Bifidobacteria infantis and Lactobacillus acidophilus in combination may prevent NEC. These meta-analyses suggest that these probiotics should be used in routine care of premature infants. Other clinicians, however, suggest caution, holding out for a single protocol multicenter trial before routine use can be suggested.

Parents' search for evidence-based practice: a personal story

Many clients engage in an intense search for evidence related to the diagnosis, prognosis and intervention options of their (or their dependent's) health condition. A client-based search for evidence poses challenges from a client and clinician perspective and evolves the client-clinician relationship. This paper describes the meaning of searching for health evidence by health-care clients such as parents of hospitalised children through a personal story. I discuss the subjective search for evidence-based health information, interpretation and transfer of information as well as its impact on providers. In order to implement client-centred care and evidence-based practice health care organisations and providers need to take an active role in guiding clients in effective health information-seeking behaviour and to develop mechanisms for processing evidence presented by clients.

Bowel sonography in sepsis with pathological correlation: an experimental study

BACKGROUND

Sepsis predisposes full-term infants to necrotizing enterocolitis (NEC). As such, experimental induction of NEC was applied to a sepsis model to evaluate the potential role of US in the early diagnosis of NEC in full-term infants.

OBJECTIVE

To evaluate the resistive index (RI) of the superior mesenteric artery (SMA) on Doppler sonography in experimentally induced sepsis and correlate it with the pathological findings.

MATERIALS AND METHODS

Fifteen 1-week-old New Zealand white rabbits (control group n = 3, sepsis group n = 12) were used in this study. We injected 1 mg/kg of E. coli O55-B5 lipopolysaccharide (LPS) into 12 rabbits to induce sepsis. Then we conducted grayscale evaluation of the caliber of the abdominal aorta as well as bowel wall thickness and echogenicity. In addition, we measured peak systolic and end-diastolic velocities and SMA RI on Doppler sonography. Pathological findings were analyzed and correlated with RI readings. Peak systolic and end-diastolic velocities and SMA RI values were analyzed statistically at each hour using the Wilcoxon rank sum test; the control and sepsis groups were compared using the Mann-Whitney test.

RESULTS

The bowel wall thickness in the sepsis group was significantly increased after LPS injection. The caliber of the abdominal aorta in the sepsis group was significantly decreased after LPS injection. There were echogenic foci (<10 in axial plane) in the bowel wall after LPS injection. Peak systolic velocity in the sepsis group was not significantly changed, but end-diastolic velocity was decreased. SMA RIs in the sepsis group were significantly increased post-LPS injection from baseline. In the control group there were no significant changes in bowel wall thickness, abdominal aorta caliber, bowel wall echogenicity or peak systolic and end-diastolic velocities and RIs. Pathologically, eight of the 12 rabbits in the sepsis group showed grade 1 intestinal injury, three showed grade 2 injury and one showed grade 3 injury. SMA RIs were higher in grades 2 and 3 than in grade 1 when measured at 2 h and 4 h.

CONCLUSION

Sepsis caused necrotic injury in the animal models, and these findings were accompanied by significant changes on Doppler US. These findings could facilitate early detection of intestinal injury in septic infants with NEC.

Probiotics and prebiotics in preterm infants: where are we? Where are we going?

BACKGROUND

Uncertainty exists regarding the efficacy and safety of using probiotics and prebiotics in preterm infants.

AIM

To review the evidence on the effects of administering probiotics and/or prebiotics to preterm infants.

METHODS

MEDLINE and the Cochrane Library were searched in August 2008. A supplemental search was conducted in July 2009. Only systematic reviews/meta-analyses and randomized controlled trials (RCTs) that evaluated the effects of probiotics and/or prebiotics on relevant short- and long-term primarily clinically important health outcomes published in the English language were included.

RESULTS

One systematic review and 2 well-performed meta-analyses suggest that probiotics reduce the risk of necrotizing enterocolitis (NEC) (stage > or =2). One subsequently published RCT reported similar results. The 2 meta-analyses also demonstrated that probiotics reduce the risk of death due to all causes, but do not have an effect on the risk of sepsis or death due to NEC. Regarding prebiotics, one meta-analysis of 4 RCTs demonstrated that prebiotic-supplemented formula increases stool colony counts of bifidobacteria and lactobacilli in preterm neonates without adversely affecting weight gain. Because of the limited data regarding synbiotics, the relationship between their use and clinical outcomes in preterm infants remains unclear.

CONCLUSIONS

The findings from the 2 meta-analyses of the effects of probiotic administration on the prevention of NEC show potential for such dietary supplementation. However, they must be interpreted with caution because the beneficial effects of probiotics seem to be strain specific, thus, pooling data from different strains may result in misleading conclusions. Before the routine use of probiotics and/or prebiotics in preterm infants, data regarding which products should be administered, at what dose, and for how long are needed.

Interval between clinical presentation of necrotizing enterocolitis and bowel perforation in neonates

OBJECTIVE

To define the interval between clinical presentation of necrotizing enterocolitis (NEC) and bowel perforation in neonates.

METHODS

Charts of neonates with discharge diagnosis of NEC (n = 124) from our NICU during 2004-2008 were retrospectively reviewed. Demographic data were collected. Acute episode of NEC was defined as the interval between clinical presentations to resumption of enteral feeds. Neonates are followed, as a standard of care, clinically and radiologically until resumption of enteral feeds at the discretion of the attending clinician. Abdominal radiograph results were reviewed serially to determine the interval between clinical presentation and bowel perforation using pneumoperitoneum as the surrogate radiological marker. Histological report of resected bowel specimens was reviewed for coagulative necrosis as evidence of NEC and to exclude spontaneous intestinal perforation (SIP). Neonates with stage 1 NEC and SIP were excluded from the results.

RESULTS

105 neonates with stage 2 NEC were included in the study. Forty-six needed surgical treatment (group 2) and 59 did not need surgery (group 1). Twenty-six (26/46, 56%) group 2 neonates had bowel perforation and hence required surgery. Pneumoperitoneum was noted at a median interval of 1 day after presentation of symptoms. Twenty neonates in group 2 needed surgery for clinical indications including worsening clinical examination, thrombocytopenia or persistent metabolic acidosis. Fifty-nine neonates (group 1) were treated with bowel rest, antibiotics and parenteral nutrition. Group 2 neonates were significantly more premature, weighed less and had less radiographs than group 1 neonates. Mortality was significantly higher in group 2 compared to group 1.

CONCLUSION

Bowel perforation occurs at a median interval of 1 day after clinical presentation of NEC. Neonates not needing surgery for their disease are exposed to significantly more radiographs than those needing surgery. Radiological evaluation can be safely minimized or eliminated after 2 days of presentation.

Prevention of necrotising enterocolitis: Year 2004 and beyond

The incidence of necrotising enterocolitis (NEC) has not changed significantly despite the dramatic advances in perinatal-neonatal care. The absolute number of survivors of NEC is expected to rise, as prevention of prematurity, the single most important risk factor for the illness, continues to be difficult. Prevention of NEC has thus become an area of research priority. Given the role of inflammatory mediators in its pathogenesis newer immune modulators are being studied as potential agents for prevention/treatment of NEC. Caution, however, is warranted because the failure of sepsis trials in adults has clearly indicated that the concept of down-regulating the inflammatory response is deceptively simple. Clinical trials of any such promising preventative agent(s) need to be designed carefully and must include long-term neurodevelopmental outcomes as almost an entire population of high-risk preterm neonates will be exposed to their adverse effects. As new frontiers continue to be explored, the proven benefits of simple and safe interventions like antenatal glucocorticoid therapy and the preferential use of breast milk for feeding high-risk neonates must not be forgotten. Given that a single effective agent is unlikely in the near future, utilizing a package of "potentially better practices" seems to be the most appropriate strategy to prevent and minimize NEC.

Association of Escherichia coli O157:H7 with necrotizing enterocolitis in a full-term infant

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency of the neonate. NEC is predominantly seen in premature infants; however, in rare instances it can affect full-term infants as well. Although the pathogenesis of NEC remains elusive, it is well established that bacterial colonization is required for development of this disease. In this report, we present a case of a full-term infant, who developed a very aggressive form of NEC and was found to have Escherichia coli (E. coli) O157:H7 both in stool and blood cultures. Unfortunately, despite aggressive surgical and intensive care management, this infant suffered pan-intestinal necrosis and expired. We were not able to establish the route of transmission. To our knowledge, this is the first report of the association of E. coli O157:H7 with NEC.

Neonatal necrotizing enterocolitis

Necrotizing enterocolitis (NEC) remains a major cause of morbidity and death in neonates. The 30% to 50% mortality rate for NEC with perforation has not changed appreciably in the past 30 years. The critical relevant outcomes following NEC include survival, gastrointestinal function, and neurodevelopmental status. In each of these areas, initial anecdotal and case-series analysis has been followed by studies using more sophisticated methods of analysis. The single most important predictor of outcome, besides gestational age, is whether or not the disease has progressed to the point requiring surgical intervention. Patients with NEC requiring operation have a high mortality. Moreover, the vast majority of morbidity following NEC occurs in the patients who survive following operation. The purpose of this review is to examine the evolution of evidence regarding outcomes for patients with NEC and to provide an update on our current state of knowledge.

Necrotizing enterocolitis: recent scientific advances in pathophysiology and prevention

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality among infants in the neonatal intensive care unit. Here we review the epidemiology and pathophysiology of NEC, with an emphasis on the latest research findings and potential areas for future research. NEC continues to be one of the most devastating and unpredictable diseases affecting premature infants. Despite decades of research, the pathogenesis of this disease remains unclear, and prevention and treatment strategies are limited. Hopefully, future studies aimed at understanding premature intestinal defenses, commensal or probiotic bacterial influences, and possible genetic predisposition will lead to the improvement of prevention and treatment strategies.

Necrotizing enterocolitis

In necrotizing enterocolitis (NEC) the small (most often distal) and/or large bowel becomes injured, develops intramural air, and may progress to frank necrosis with perforation. Even with early, aggressive treatment, the progression of necrosis, which is highly characteristic of NEC, can lead to sepsis and death. This article reviews the current scientific knowledge related to the etiology and pathogenesis of NEC and discusses some possible preventive measures.

Necrotizing enterocolitis in term neonates: data from a multihospital health-care system

OBJECTIVE

In the past 5(1/2) years, 30 term or near-term neonates in the Intermountain Healthcare system developed necrotizing enterocolitis (NEC) Bell's stage > or =II. We sought to identify possible explanations for why these patients developed NEC, by comparing them with 5847 others that did not develop NEC, from the same hospitals and of the same gestational ages, cared for during the same 5 1/2-year period.

STUDY DESIGN

Data were collected from neonates admitted to any of the Intermountain Healthcare NICUs with a birth date from 1 January 2001 to 30 June 2006, and a gestational age >36 weeks. A variety of patient features and feeding practices were compared between those that did vs did not develop NEC.

RESULT

Forty-one neonates >36 weeks gestation were listed in the discharge records as having NEC of Bell's stage II or higher. However, on review of these 41 medical records, 11 were seen to have had NEC of Bell's stage I, whereas the remaining 30 had radiographs and clinical courses indicative of Bell's stage > or =II. Those 30 formed the basis of this study. Twenty-eight of the 30 developed NEC after having been admitted to an NICU for some other reason; the other two developed NEC at home, within 2 days of being discharged from an NICU. The 30 that developed NEC were more likely than the 5847 that did not develop NEC, to have congenital heart disease (P=0.000), polycythemia (P=0.002), early-onset bacterial sepsis (P=0.004) or hypotension (P=0.017). All 30 received enteral feedings before NEC developed; 29 were fed either artificial formula or a mixture of formula and breast milk. The one that was exclusively fed human milk was fed human milk with added fortifier (24 cal/oz). The 30 that developed NEC were more likely to be fed formula exclusively (P=0.000). Seven of the 30 had a laparotomy for NEC; two of the seven had total bowel necrosis and support was withdrawn. The other five had perforations and bowel resections. The mortality rate was 13% (4/30).

CONCLUSION

In our series, NEC among term or near-term neonates was exclusively a complication developing among patients already admitted to a NICU for some other reason. We speculate that the combination of reduced mesenteric perfusion and feeding with artificial formula were factors predisposing them to develop NEC.

Probiotics for prevention of necrotising enterocolitis in preterm neonates with very low birthweight: a systematic review of randomised controlled trials

BACKGROUND

Results of recent clinical trials suggest that probiotic supplementation reduces the risk of necrotising enterocolitis in preterm neonates. We aimed to systematically review randomised controlled trials evaluating efficacy and safety of any probiotic supplementation (started within first 10 days, duration > or =7 days) in preventing stage 2 or greater necrotising enterocolitis in preterm neonates (gestation <33 weeks) with very low birthweight (<1500 g).

METHODS

We followed the standard search strategy of the Cochrane Neonatal Review Group. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, CINAHL databases, and proceedings of the Pediatric Academic Society meetings (from 1980) and Pediatric Gastroenterology conferences (from 1980) in November, 2006.

RESULTS

Seven of 12 randomised controlled trials retrieved (n=1393) were eligible for inclusion in the analysis. Meta-analysis using a fixed effects model estimated a lower risk of necrotising enterocolitis (relative risk 0.36, 95% CI 0.20-0.65) in the probiotic group than in controls. Risk of sepsis did not differ significantly between groups (0.94, 0.74-1.20). Risk of death was reduced in the probiotic group (0.47, 0.30-0.73). The time to full feeds was significantly shorter in the probiotic group (weighted mean difference -2.74 days, 95% CI -4.98 to -0.51) than in controls.

CONCLUSION

Probiotics might reduce the risk of necrotising enterocolitis in preterm neonates with less than 33 weeks' gestation. However, the short-term and long-term safety of probiotics needs to be assessed in large trials. Unanswered questions include the dose, duration, and type of probiotic agents (species, strain, single or combined, live or killed) used for supplementation.

The role of the intestinal barrier in the pathogenesis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in neonates and is increasing in frequency because of recent advances in neonatal care. NEC develops in a stressed preterm infant in the setting of intestinal barrier disruption, systemic inflammation, and leads to, multisystem organ failure. The intestinal barrier lies at the interface between microbes within the intestinal lumen and the immune system of the host, and has both immunological and mechanical components. These components serve to protect the host from invading pathogens and, at the same time, provide a surface area for nutrient absorption. Factors that lead to impairments in the function of the intestinal barrier may predispose the host to the invasion of gut-derived microbes and to the development of systemic inflammatory disease. This process, termed "bacterial translocation," may be compounded during instances in which the mechanisms that regulate the repair of the intestinal barrier are disrupted. Bacterial translocation is of particular concern to the newborn patient, in which immaturity of the mechanical barrier and incomplete development of the host immune system combine to render the host at particular risk for the development of intestinal inflammation. This review will serve to provide an overview of recent evidence regarding the components of the intestinal barrier, and the mechanisms by which disruptions in barrier function may contribute to the pathogenesis of NEC.

Necrotising enterocolitis

Necrotising enterocolitis is one of the most common gastrointestinal emergencies in newborn infants. Here we review the epidemiology, clinical presentation, and pathophysiology of the disease, as well as strategies for diagnosis, management, and prevention. Necrotising enterocolitis is one of the most devastating and unpredictable diseases affecting premature infants. Despite decades of research, its pathogenesis remains unclear; diagnosis can be difficult; and treatment is challenging. We will need to improve our understanding of intestinal defences in premature infants, dietary and bacterial factors, and genetic effects that could predispose infants to necrotising enterocolitis before we can develop new strategies for prevention and treatment.

Intraabdominal infections in infants and children: descriptions and definitions

OBJECTIVE

To define intraabdominal infections in infants and children.

DESIGN

Summary of the literature with review and consensus by experts in the field.

RESULTS

Intraabdominal infections are common in infants and children and comprise a broad range of disorders of greatly variable severity. In addition to microbiologically mediated processes, other inflammatory disorders frequently present similar clinical syndromes. More aggressive and effective therapy for prematurity, chronic diseases of childhood, malignancies, immunodeficiencies, and organ failure, including transplantation, is likely to increase the frequency with which some of these infections are encountered. Only a limited number of processes have been clearly defined in the pediatric literature.

CONCLUSIONS

Criteria defining intraabdominal infection are proposed based on reports in the pediatric literature and expert opinion. Additional study of individual disorders, diagnostic criteria, and approach to management is warranted.

Variations in incidence of necrotizing enterocolitis in Canadian neonatal intensive care units

OBJECTIVES

Necrotizing enterocolitis (NEC) is the most common acquired intestinal disease of neonates. Previous reports on incidence have generally examined small cohorts of extremely low-birth-weight infants and have not examined risk-adjusted variations among neonatal intensive care units (NICUs). The authors examined risk-adjusted variations in the incidence of NEC in a large group of Canadian NICUs and explored possible therapy-related risks.

METHODS

The authors obtained data on 18,234 infants admitted to 17 tertiary level Canadian NICUs from January 1996 to October 1997. They used multivariate logistic regression analysis to examine the inter-NICU variation in incidence of NEC, with adjustment for population risk factors and admission illness severity, and explored therapy-related variables.

RESULTS

The incidence of NEC was 6.6% (n = 238) among 3,628 infants with birth weight < or = 1,500 g (VLBW), and 0.7% (n = 98) among 14,606 infants with birth weight > 1,500 g (HBW). Multivariate logistic regression analysis showed that for VLBW infants, NEC was associated with lower gestational age and treatment for hypotension and patent ductus arteriosus. Among HBW infants, NEC was associated with lower gestational age, presence of congenital anomalies (cardiovascular, digestive, musculoskeletal, multiple systems) and need for assisted ventilation. There was no significant variation in the risk-adjusted incidence of NEC among NICUs, with the exception of one NICU reporting no cases of NEC.

CONCLUSIONS

Risk factors for NEC were different in VLBW and HBW infants. There was no significant variation in the risk-adjusted incidence of NEC among Canadian NICUs, with one possible exception.

Necrotizing enterocolitis in full-term infants: case-control study and review of the literature

OBJECTIVE

To examine the increasing number of full-term infants at our hospital exhibiting necrotizing enterocolitis (NEC) in order to characterize these cases and to discover common risk factors.

METHODS

Medical charts were reviewed for all full-term infants (gestational age > 36 weeks) that were born in our institution during a 5-year period (from January 1, 1998 to December 31, 2002) and that developed definite NEC. Data regarding the rate of Cesarean section (CS) in our institution over the study period and five years prior to the study was also recorded.

RESULTS

During the 5 years of the study, 14 full-term infants were found to have NEC. The incidence of NEC in full-term infants increased from 0.16 to 0.71 per 1000 live births in the 5-year period. Mean birth weight was 2829 g. All the NEC infants except one were delivered by CS, and all of them were fed either with a mixture of breast milk and formula or entirely by formula. Seven of the infants (50%) had no major known risk factors predisposing them for NEC. Mean age of disease onset was very early (4.1 days) in most of the infants (12 infants), and the colon was the main NEC site. The short-term outcome was favorable in all but one case, which required explorative laparotomy for intestinal perforation. The number of infants born by CS has been steadily increasing, and was almost three times greater during the study period in comparison to the preceding years.

CONCLUSIONS

The etiology of NEC in the full-term population seems to differ from the etiology for the preterm group in its intestinal location and in the timing of its onset. The increase in the rate of CS over the years might be related to the concurrent increase in NEC, and this relationship should be further investigated.Journal

Current issues in the management of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common surgical emergency in the neonatal intensive care unit and remains a major cause of death in neonates. Although the pathophysiology of NEC has not been completely elucidated, progress has been made in the characterization of the molecular events which may take place during an episode of ischemia. This possible initiating event is followed by a complex cascade of inflammatory mediators active in NEC: epidermal growth factor, platelet-activating factor, and, nitric oxide. Additionally, unique characteristics of the premature gut are thought to be crucial to the development of NEC. The diagnosis of NEC continues to be based on clinical and radiographic features. Several new laboratory tests are under investigation for the purposes of earlier diagnosis, but none have prevailed at this time. Both exploratory laparotomy, with intestinal resection and peritoneal drainage are widely practiced. Mortality rates remain high and have improved little over the last couple of decades. Therefore, prevention remains crucial in order to decrease the incidence of NEC. Cautious feeding regimens, the use of maternal breast milk, passive immunization, and the use of probiotics have all been suggested but not proven as possible preventive methods. Although many advances have been made, significant opportunity remains to improve our understanding of the disease process and to develop better strategies for prevention and treatment.

Nutrition and the critically ill horse

A nutritional plan should be incorporated into every treatment plan of the critically ill patient. Weight loss and cachexia are the result of prevalence of catabolic processes over anabolic processes in addition to absolute or relative increased demands and decreased food intake.

Neonatal necrotizing enterocolitis: an overview

PURPOSE OF REVIEW

Necrotizing enterocolitis represents a disease entity that remains quite challenging for neonatologists all around the world, in that its aetiology has yet to be revealed, but it is the cause of death for many premature infants each year, affecting up to 28% of very low birthweight infants. This is an attempt to improve the management of affected babies and stimulate more research concerning new diagnostic tools.

RECENT FINDINGS

Current trends in the field of (early) diagnosis, such as: (1) imaging techniques, e.g. contrast radiography, portal vein ultrasonography, magnetic resonance, radionuclide scanning; (2) gastrointestinal tonometry; (3) the detection of biochemical markers, cytokines, growth factors; and (4) the determination of the mean peak hydrogen: carbon dioxide ratio excreted in breath, are only some of those mentioned. Various novel preventive techniques are also presented, among which platelet-activating factor acetyl hydrolase activity enhancement, platelet-activating factor receptor antagonists and probiotics, such as Bifidobacterium infantis and Lactobacillus acidophilus, seem quite promising. Regarding treatment, the use of oxygenated perfluorocarbon has added to the limited alternatives available. These data along with other recent discoveries concerning the risk factors and pathogenesis of this disease create a full picture of the current opinion on this topic.

SUMMARY

Keeping in mind that the key to confronting such a devastating disorder as necrotizing enterocolitis is early diagnosis and prevention, both clinically applicable and experimental advances are presented with the hope of improving the survival rates of patients affected.

Current controversies in the understanding of necrotizing enterocolitis. Part 1

Necrotizing enterocolitis (NEC) has widespread implications for neonates. While mostly affecting preterm neonates, full-term neonates, especially those with congenital heart disease, are also at risk. Although the exact pathogenesis of NEC remains elusive, three major factors, a pathogenic organism, enteral feedings, and bowel compromise, coalesce in at-risk neonates to produce bowel injury. Initiation of the inflammatory cascade likely serves as a common pathway for the disorder. Clinical signs and symptoms range from mild feeding intolerance with abdominal distension to catastrophic disease with bowel perforation, peritonitis, and cardiovascular collapse. Vigilant assessment of at-risk neonates is crucial. When conservative medical management fails to halt injury, surgical intervention is often needed. Strategies to decrease the incidence and ultimately prevent NEC loom on the horizon, such as exclusive use of human breastmilk for enteral feedings and administration of probiotics.