Necrotizing enterocolitis: laboratory indicators of surgical disease

Methods of identifying surgical Necrotizing Enterocolitis-a systematic review and meta-analysis

BACKGROUND

Current data suggests potential benefit of earlier surgery for necrotizing enterocolitis (NEC) however this requires accurate prognostication early in the disease course. This study aims to identify and determine the effectiveness of previously reported methods or tests for the identification of surgical NEC.

METHODS

Systematic review and meta-analysis with registration on PROSPERO including articles describing a method of identifying surgical NEC. Outcomes of interest were effectiveness and repeatability of index test.

RESULTS

Of the 190 full-text articles screened, 90 studies were included which contained 114 methods of identifying surgical NEC in 9546 infants. Of these methods, 44 were a scoring system, 37 a single biomarker, 24 an imaging method, and 9 an invasive method. Sensitivity and specificity ranged from 12.8-100% to 13-100%, respectively. Some methods (9.6%) provided insufficient methods for repeatability within clinical practice or research. Meta-analyses were possible for only 2 methods, the metabolic derangement 7 score and abdominal ultrasound.

CONCLUSIONS

A range of methods for identifying surgical NEC have been identified with varying overall performance and uncertainties about reproducibility and superiority of any method. External validation in large multicentre datasets should allow direct comparison of accuracy and prospective study should evaluate impact on clinical outcomes.

IMPACT

Earlier identification of need for surgery in necrotizing enterocolitis (NEC) has the potential to improve the unfavourable outcomes in this condition. As such, many methods have been developed and reported to allow earlier identification of surgical NEC. This study is the first synthesis of the literature which identifies previously reported methods and the effectiveness of these. Many methods, including scoring systems and biomarkers, appear effective for prognostication in NEC and external validation is now required in multicentre datasets prior to clinical utility.

SNAPPE-II and MDAS scores as predictors for surgical intervention in very low birth weight neonates with necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common life-threatening gastrointestinal emergency in preterm and term neonates, with the majority of cases affecting neonates classified as very low birth weight (VLBW, bw <1500 g). Scores for neonatal acute physiology-perinatal extension-II (SNAPPE-II) and metabolic derangement acuity score (MDAS) have been developed and utilized to assess neonatal morbidity and mortality including the subset of VLBW neonates. Serial SNAPPE-II and MDAS scores have been reported in neonates with necrotizing enterocolitis to assist in surgical management, yielding mixed results.

OBJECTIVE

To determine the relationship between clinical and/or laboratory deterioration using SNAPPE-II and MDAS scores measured at the time of NEC diagnosis and surgical management of NEC.

METHODS

We retrospectively evaluated preterm neonates ≥23 weeks gestational age who developed pneumatosis intestinalis on radiographic imaging coupled with clinical signs of NEC. SNAPPE-II and MDAS scores were calculated within twelve hours of birth and within twelve hours of initial finding of pneumatosis intestinalis. Baseline characteristics and clinical variables between those who did and did not require surgical intervention were compared. Logistic regression and receiver - operator characteristics (ROC) curve analyses were also performed, and areas under the curve (AUC) computed, to assess the performance of SNAPPE-II and MDAS scoring systems to differentiate neonates with NEC in the two groups.

RESULTS

Sixty-four neonates were evaluated in our study of which 20 required surgical management of NEC. While the baseline SNAPPE-II and MDAS scores did not differ between the surgical management and medical management only groups, when rescored within 12 h of NEC diagnosis, the surgical management group had significantly higher SNAPPE -II (38 (18.5-69) vs. 19 (10-34.5), p = .04) and MDAS (2.5 (1-3) vs. 1 (0-2), p = .0004) scores. The AUCs for MDAS 0.77 (95% CI 0.65-0.89 and 0.71 (95% CI 0.57-0.85) for SNAPPE-II, indicating an acceptable level of diagnostic ability of both scoring systems to differentiate between those who did and did not need surgical management.

CONCLUSION

SNAPPE II and MDAS scores performed within 12 h of NEC diagnosis may be useful in predicting which preterm VLBW neonates will require surgical intervention.

Enterostomy complications in necrotizing enterocolitis (NEC) surgery, a retrospective chart review at Odense University Hospital

Background

The aim was to investigate the incidence of postoperative complications to surgery for necrotizing enterocolitis (NEC) with primary focus on enterostomy related complications.

Methods

A retrospective chart review of surgically treated NEC during the period from 2008 to 2014 was performed. Enterostomy with secondary anastomosis was our standard treatment. Postoperative complications were classified according to the Clavien-Dindo Classification (CDC).

Results

Forty-two cases were included in the study. NEC was most frequently located in the small bowel and the length of resected intestine was median 15 cm (2–50). Thirty-nine (93%) patients received an ileostomy and the rest a colostomy. Twenty-two (52%) patients underwent a total of 35 reoperations, and 25 (71%) of these were stoma related with stenosis was the most frequent cause, other causes of reoperation were re-NEC, high-output ileostomy, Ileus and second look.

Conclusions

The rate of reoperation due to complications was high and most often caused by stoma related complications.

Congenital Heart Disease Increases Mortality in Neonates With Necrotizing Enterocolitis

Background: Studies on the influence of congenital heart disease (CHD) on neonates with necrotizing enterocolitis (NEC) have produced varied results. We therefore examined the influence of CHD on NEC outcomes. Methods: We carried out a retrospective single-center study including infants with confirmed NEC, treated between 2004 and 2017. We excluded patients with isolated patent ductus arteriosus or pulmonary hypertension (n = 45) and compared outcomes of patients with hemodynamically relevant CHD (n = 38) and those without CHD (n = 91). Results: Patients with CHD were more mature than those without CHD [gestational age, median, 95% confidence interval (CI95), 37.1, 34.5-37.2w, vs. 32.6, 31.9-33.3w; P < 0.01]. The presence of CHD did not influence the frequencies of severe disease (overall 21% Bell stage III), nor surgical interventions (overall 30%), the occurrence of intestinal complications (overall 13%), nor the duration of hospitalization (overall 38 days in survivors). The overall mortality as well as NEC-related mortality was increased with the presence of CHD, being 50% (19 out of 38) and 13% (5 out of 38), respectively, when compared to patients without CHD, being 8% (7 out of 91) and 3% (3 out of 91). The presence of CHD and of advanced NEC stage III were independent predictors of NEC-associated fatalities with multivariable odds ratios (CI95) of 7.0, 1.3-39.5 for CHD, and of 3.4, 1.6-7.5 for stage III disease. Conclusions: While some outcome parameters in neonates with NEC remained unaffected by the presence of CHD, the mortality risk for patients with CHD was seven times higher than without CHD.

Ultrasonography and radiography findings predicted the need for surgery in patients with necrotising enterocolitis without pneumoperitoneum

AIM

The timing of surgical intervention in patients with necrotising enterocolitis (NEC) without pneumoperitoneum remains unclear. This study aimed to identify the predictors associated with surgical intervention in such patients and to assess how effective imaging reports were as an aid to surgical decision-making.

METHODS

We collected clinical data, laboratory investigations and imaging findings on NEC patients without pneumoperitoneum. A critical imaging report was defined as persistent dilation of bowel loops and evidence of portal venous gas on radiography and thickening of the bowel wall, absent peristalsis and evidence of echogenic-free fluid on sonography. Independent predictors of surgical NEC were identified using multivariate logistic regression analysis. Sensitivity and specificity analyses were performed for the imaging findings, and receiver operator characteristic curve analysis was used to evaluate the predictive accuracy.

RESULTS

Of the 238 neonates studied, 54 (22.69%) required surgical intervention. The multivariate logistic regression analysis showed that abdominal erythema, C-reactive protein levels and the critical imaging report were independent predictors of the need for surgical intervention. The critical imaging report was the most powerful predictor of surgical NEC.

CONCLUSION

Both ultrasonography and radiography findings proved helpful in predicting the need for surgery in NEC without pneumoperitoneum.

Predicting disease severity of necrotizing enterocolitis: how to identify infants for future novel therapies

Necrotizing enterocolitis (NEC) remains a very devastating problem within the very low birth weight neonatal population. Several experimental therapies are being tested in animal models and soon may be ready for human trials. Despite this progress, we currently have no way to identify infants who would be optimal targets for therapy. Specifically, we are unable to predict which infants will progress to the more severe Bell's stage of disease that may necessitate surgery. Ideally, an algorithm could be constructed that would encompass multiple neonatal and maternal risk factors as well as potential biologic markers of disease so that these infants could be identified in a more timely fashion. This review summarizes the known risk factors and biomarkers of disease in hopes of stimulating clinical research to identify such an “early warning” NEC algorithm.

Could clinical scores guide the surgical treatment of necrotizing enterocolitis?

PURPOSE

Test the diagnostic reliability of the score for neonatal acute physiology-perinatal extension-II (SNAPPE-II) and the metabolic derangement acuity score (MDAS) as predictors of surgery in patients with necrotizing enterocolitis (NEC).

METHODS

The SNAPPE-II and the MDAS were applied to 99 patients with NEC. Both the scores were calculated at the moment of diagnosis (T(0)) and when surgical assessment was required (T(1)). The main outcome was the need of surgical revision. Comparison between models was made through their receiver operator characteristics (ROC) curves.

RESULTS

Thirty-five patients required surgical treatment (group A) and 64 responded to medical therapy (group B). Median SNAPPE-II was 22 versus 5 for group A (U test 621, p = 0.002) at T(0); and 22 versus 10 for group A (U test 487, p = 0.01) at T(1). Measuring the value of the SNAPPE-II as a predictor of surgery, the ROC curve was 0.69 (CI 95%, 0.57-0.80) at T(0) and 0.67 (CI 95%, 0.55-0.80) at T(1). Median MDAS were 2 for both groups A and B at T(0) (U test 890.5, p = 0.113) and 2 versus 1.5 for group A at T(1) (U test 570, p = 0.043). The ROC curve for MDAS was 0.59 (CI 95%, 0.47-0.71) at T(0) and 0.64 (CI 95%, 0.52-0.77) at T(1).

CONCLUSIONS

The diagnostic performance of the SNAPPE-II offers mild results in the moment of the diagnosis of NEC, and at T(1). The MDAS is non significant at T(0) and obtains moderate results at T(1). These results do not encourage using the SNAPPE-II and the MDAS as definite tools to decide for surgical treatment of the patients affected by NEC.

Intraperitoneal microdialysis in the postoperative surveillance after surgery for necrotizing enterocolitis: a preliminary report

BACKGROUND/PURPOSE

The aim of the present pilot study was to evaluate the safety and clinical application of intraperitoneal microdialysis (MD) in preterm infants operated on for necrotizing enterocolitis (NEC).

METHODS

Fourteen infants underwent MD. Two were excluded from analysis: 1 because of catheter malfunction and 1 because of fatal outcome immediately after surgery. The median MD time was 122 hours. Samples were collected every 4 hours, and the concentration of glucose, lactate, pyruvate, and glycerol was measured.

RESULTS

Three infants were reoperated on: 2 because of recurrent NEC and 1 because of ileal stenosis. In the 2 cases with recurrent NEC, changes in MD variables were found. Another had a prolonged postoperative period owing to diffuse fecal peritonitis. The values of MD normalized along with the return of bowel function. In 8 infants, the postoperative course was uncomplicated. The results of peritoneal MD in patients with complications were significantly different from those with an uncomplicated course (lactate/pyruvate ratio and glucose concentration).

CONCLUSION

Peritoneal MD is a safe procedure and an applicable method in surveillance of the metabolic and inflammatory changes in the peritoneal cavity after surgery for NEC. Larger series are needed to evaluate the clinical significance and use of this method.

A simple presurgical necrotizing enterocolitis-mortality scoring system

OBJECTIVE

To assess the relationship between early laboratory parameters, disease severity, type of management (surgical or conservative) and outcome in necrotizing enterocolitis (NEC).

STUDY DESIGN

Retrospective collection and analysis of data from infants treated in a single tertiary care center (1980 to 2002). Data were collected on disease severity (Bell stage), birth weight (BW), gestational age (GA) and pre-intervention laboratory parameters (leukocyte and platelet counts, hemoglobin, lactate, C-reactive protein).

RESULTS

Data from 128 infants were sufficient for analysis. Factors significantly associated with survival were Bell stage (P<0.05), lactate (P<0.05), BW and GA (P<0.01, P<0.001, respectively). From receiver operating characteristics curves, the highest predictive value resulted from a score with 0 to 8 points combining BW, Bell stage, lactate and platelet count (P<0.001). At a cutoff level of 4.5 sensitivity and specificity for predicting survival were 0.71 and 0.72, respectively.

CONCLUSION

Some single parameters were associated with poor outcome in NEC. Optimal risk stratification was achieved by combining several parameters in a score.

Laboratory parameters predictive of developing necrotizing enterocolitis in infants born before 33 weeks of gestation

PURPOSE

The aim of this study was to identify laboratory findings predictive of necrotizing enterocolitis (NEC).

METHODS

Prospective follow-up of 140 infants of less than 33 weeks of gestation. Twenty-six infants developed NEC (grades I to III, criteria of Bell et al [Ann Surg 1978;187:1-7]) (NEC group). For each, 2 birth-weight, gestational age- and postnatal age-matched controls were selected (control group). Blood counts, glucose and electrolyte levels, C-reactive protein, and acid-base balance 3 days, 2 days, and 1 day before and at the onset of NEC and at corresponding ages from the controls were recorded.

RESULTS

Metabolic acidosis occurred, the platelet levels decreased, and the blood glucose increased on successive days in the infants with grade NEC II-III. At the onset of NEC, the infants had significantly lower platelet and higher blood glucose levels compared with controls. More than half of infants with intestinal perforation had leukocyte levels above 30 x 10(9)/L and pH less than 7.25, and their mean blood glucose levels increased to more than 1.5 mmol/L in 24 hours. The remaining parameters were not useful.

CONCLUSION

A persistent metabolic acidosis, decreasing platelet, and increasing blood glucose level on several successive days might predict a developing NEC, and leukocyte values above 30 x 10(9)/L, pH less than 7.25, and a blood glucose rise by 1.5 mmol/L or more within 24 hours predict NEC with intestinal perforation. Such findings should alert the physician to look for signs of NEC in a preterm infant.

Hematologic abnormalities in severe neonatal necrotizing enterocolitis: 25 years later

Necrotizing enterocolitis (NEC), the most common surgical emergency in newborns, remains a therapeutic challenge for clinicians. The hematological manifestations associated with NEC were first described 25 years ago. This review discusses current knowledge of the pathophysiology involved in disturbances in megakaryocytopoiesis, coagulation, leukopoiesis, and erythropoiesis that accompany the clinical entity NEC. The discussion includes current understanding of and potential strategies for treating the hematopoietic disturbances that occur secondary to NEC.

Are localized intestinal perforations distinct from necrotizing enterocolitis?

BACKGROUND/PURPOSE

Localized intestinal perforation (LP) is thought to be a distinct entity when compared with perforation associated with necrotizing enterocolitis (NEC). Studies have indicated that LP is more amenable to percutaneous drainage and associated with a better outcome. We sought to determine whether LP and NEC could be distinguished based on clinical parameters alone.

METHODS

A retrospective review of 40 neonates with gastrointestinal perforations between January 1990 and May 1998 was performed. All had undergone laparotomy and had histologic specimens available for evaluation.

RESULTS

Twenty-one neonates had necrotizing enterocolitis (NEC), and 19 had localized perforation (LP) based on histologic criteria. More neonates with LP were exposed to prenatal indomethacin (37% v 5%; P <.05), received intravenous dexamethasone (42% v 10%; P <.05), had umbilical artery catheters (63% v 14%; P <.05), and had a higher white blood cell (WBC) count (27.1 +/- 23.1 v 14.3 +/- 11.5; P <.05). More neonates with NEC had pneumatosis intestinalis (47% v 11%; P <.05). No significant differences existed in enteral feeding (16% LP v 38% NEC) or overall mortality rate (37% LP v 38% NEC). No statistical differences in the timing of perforation or clinical presentation were found.

CONCLUSIONS

NEC and LP are difficult to distinguish based on clinical parameters alone. The authors did find associations between LP and prenatal indomethacin, intravenous dexamethasone, umbilical artery catheters, and a higher WBC count. Mortality rate and clinical outcome were nearly identical in both groups. Pneumatosis intestinalis, thought to be pathognomonic for NEC, was seen on abdominal radiograph in 2 babies with histologically proven LP.

Neonatal necrotizing enterocolitis: clinical considerations and pathogenetic concepts

Necrotizing enterocolitis (NEC), a disease affecting predominantly premature infants, is a leading cause of morbidity and mortality in neonatal intensive care units. Although several predisposing factors have been identified, such as prematurity, enteral feeding, and infection, its pathogenesis remains elusive. In the past 20 years, we have established several animal models of NEC in rats and found several endogenous mediators, especially platelet-activating factor (PAF), which may play a pivotal role in NEC. Injection of PAF induces intestinal necrosis, and PAF antagonists prevent the bowel injury induced by bacterial endotoxin, hypoxia, or challenge with tumor necrosis factor-a (TNF) plus endotoxin in adult rats. The same is true for lesions induced by hypoxia and enteral feeding in neonatal animals. Human patients with NEC show high levels of PAF and decreased plasma PAF-acetylhydrolase, the enzyme degrading PAF. The initial event in our experimental models of NEC is probably polymorphonuclear leukocyte (PMN) activation and adhesion to venules in the intestine, which initiates a local inflammatory reaction involving proinflammatory mediators including TNF, complement, prostaglandins, and leukotriene C4. Subsequent norepinephrine release and mesenteric vasoconstriction result in splanchnic ischemia and reperfusion. Bacterial products (e.g., endotoxin) enter the intestinal tissue during local mucosal barrier breakdown, and endotoxin synergizes with PAF to amplify the inflammation. Reactive oxygen species produced by the activated leukocytes and by intestinal epithelial xanthine oxidase may be the final pathway for tissue injury. Protective mechanisms include nitric oxide produced by the constitutive (mainly neuronal) nitric oxide synthase, and indigenous probiotics such as Bifidobacteria infantis. The former maintains intestinal perfusion and the integrity of the mucosal barrier, and the latter keep virulent bacteria in check. The development of tissue injury depends on the balance between injurious and protective mechanisms.

Magnetic resonance imaging of intestinal necrosis in preterm infants

BACKGROUND AND OBJECTIVE

Noninvasive diagnosis of intestinal necrosis is important in planning surgery in preterm infants with necrotizing enterocolitis (NEC). We aimed to assess the potential of magnetic resonance imaging (MRI) for the diagnosis of intestinal necrosis.

STUDY PARTICIPANTS AND METHODS

Abdominal MRI scans were performed in a group of preterm infants with suspected NEC and compared with surgical findings and to MRI results in a group of control infants. In addition, MRI was performed in 2 preterm infants with suspected NEC who did not require surgery.

RESULTS

Six infants with a median birth weight of 1220 g (range, 760-1770 g) and median gestational age at birth of 30 weeks (range, 28-34 weeks) were studied at a median postnatal age of 10 days (range, 4-19 days). Four infants had a bubble-like appearance in part of the intestinal wall, intramural gas, and an abnormal fluid level within bowel lumen. At surgery, NEC was found in 5 infants and sigmoid volvulus in 1. The site of the bubble-like appearance corresponded to the site of intestinal necrosis at surgery. Four control infants with a median birth weight of 1500 g (range, 730-2130 g) and a median gestational age of 31 weeks (range, 26-36 weeks) had abdominal MRI at a median postnatal age of 8 days (range, 4-70 days). None of the above findings were seen in any control infant. The bubble-like appearance was not seen in the 2 infants with suspected NEC who did not require surgery.

CONCLUSION

Abdominal MRI allows the noninvasive diagnosis of bowel necrosis. This may aid the timing of surgical intervention in preterm infants with a clinical diagnosis of NEC.gangrene, ischemia, MRI, necrotizing enterocolitis.

Plasma intestinal fatty acid binding protein in neonates with necrotizing enterocolitis: a pilot study

BACKGROUND/PURPOSE

Intestinal fatty acid-binding protein (IFABP) is found within cells at the tip of the intestinal villi, an area commonly injured when necrotizing enterocolitis (NEC) occurs. This study was undertaken to determine if measuring IFABP concentrations in the bloodstream early in the course of NEC would differentiate patients by severity before clinical findings made it clear who had stage 3 NEC and who had milder stages.

METHODS

Three plasma samples from newborn infants evaluated for NEC were obtained at symptom onset and after 8 and 24 hours. IFABP concentration was measured by radioimmunoassay. Infants were classified by the final and most severe stage of NEC, and IFABP levels were compared between groups at each sampling.

RESULTS

IFABP was detectable in blood samples from all 7 infants with stage 3 NEC compared with 3 of 24 with stages 1 or 2 NEC. Elevated plasma IFABP concentrations were detectable before clinical staging could be made in 5 of the 7 subjects with stage 3 NEC.

CONCLUSION

IFABP may be a specific marker for early identification of severe NEC.