The Use of Ultrasound in the Face of Diagnostic Uncertainty for Necrotizing Enterocolitis in Neonates Taylor Valerio1, Chethan Sathya, MD2, Alpna Aggarwal, DO2, Aaron Lipskar, MD2, Michelle Kallis, MD2, Julia Haft1 1 Zucker School of Medicine, 2 Cohen Children’s Medical Center
Background
Results
Necrotizing Enterocolitis (NEC) is a serious gastrointestinal condition that occurs mostly in premature infants and is associated with significant morbidity and mortality. Abdominal radiography (AXR) is the gold standard for evaluating neonates for suspected NEC. Pathognomonic findings of pneumatosis intestinalis (air bubbles in the walls of the intestine) and portal venous gas can be medically managed with gut rest and antibiotics, while pneumoperitoneum (intestinal perforation) requires surgical intervention. Pneumatosis intestinalis is often difficult to differentiate from stool (seen as bubbles inside the intestine) on AXR, resulting in equivocal findings and potentially unnecessary treatment. Abdominal ultrasound (AUS), although not routinely used, may serve as an adjunct diagnostic imaging modality providing real time images of pneumatosis intestinalis in cases when diagnostic uncertainty exists on AXR. Our group previously performed a retrospective chart review (20172019) of 54 infants with suspected NEC who underwent ultrasound evaluation after equivocal findings on AXR could not definitively rule in or rule out pneumatosis intestinalis and/or portal venous gas. AUS confirmed pneumatosis in 22 (40.7%) and demonstrated an absence of pneumatosis in 32 (59.3%) patients. Of the 32 patients without pneumatosis on US, 25 were not treated for NEC and 7 were determined to have NEC based on clinical criteria. The absence of pneumatosis on AUS was associated with decreased antibiotic treatment.
Methods Prospective chart review (July 2021 - ongoing) of infants undergoing evaluation for suspected NEC in the NICUs at Cohen’s Children Medical Center and North Shore University Hospital.
More studies are needed to ascertain the role of AUS in the setting of equivocal AXR in diagnosing and altering management in cases of suspected NEC
Future Directions Table 1: Descriptive data of the prospective cohort of patients who have been evaluated for suspected NEC (n=16). *Two patients expired while on antibiotics
Of the 3 cases for which AXR had equivocal findings, AUS showed positive presence of pneumatosis and portal venous gas in 1 case, was negative for pneumatosis in 1 case, and was equivocal in 1 case.
of patients who have been evaluated for suspected NEC/SIP (n=17). This table is a Case Example preliminary evaluation of the patients’ birth information, clinical presentation, and treatment time course. Table 2: Analysis of AXR and US use in the prospective cohort of patients being evaluated for NEC.
A female born at 27 weeks gestation presented on DOL #24 with abdominal distention, bloody stool, bilious residual, and multiple episodes of apnea/bradycardia/desaturation.
AXR: “Multiple air and stool filled loops of bowel without supine evidence of intraperitoneal free air or portal venous gas. There are bubbly lucencies distributed throughout the abdomen, favor gas bubbles within stool, cannot entirely exclude pneumatosis intestinalis.”
US: “No definite evidence of pneumatosis intestinalis”
As AUS continues to become more recognized as a useful adjunct in the clinical assessment of neonates with suspicion of NEC, one key aim for the future is to increase its utilization by care teams in the diagnostic work-up of patients. To this end, and given the prospective nature of this cohort, the goal is to identify patients in real time who may benefit from the utilization of AUS in their clinical assessment. A large database is being created for this prospective cohort to collect additional information including birth history, neonate and maternal comorbidities, feeding history, lab values pre- and post-suspicion for NEC, and treatment course including surgical and medical management. The goal of the database is to identify commonalities amongst patients and to guide inquiry regarding the factors that may be contributing to the incidence of NEC. Lastly, the use of AUS has been shown to be beneficial in reducing antibiotic treatment days in cases of equivocal AXR findings. The implications of these results are important for antibiotic stewardship and minimizing treatment-related and potentially avoidable negative outcomes.
Resources Chen PA, Sun JT, Lien WC, Huang CY. Ultrasound Imaging of Pneumatosis Intestinalis. J Med Ultrasound. 2019;27(4):211-212. Published 2019 Jun 7. doi:10.4103/JMU.JMU_18_19 Kallis MP, Roberts B, Aronowitz D, Shi YE, Lipskar AM, Amodio JB, Aggarwal A, Sathya C. The Impact of Ultrasound as a Diagnostic Adjunct in Cases of Suspected Necrotizing Enterocolitis with Equivocal Radiographic Findings [Manuscript]. 2021.
Pertinent patient data, clinical findings, results of AXR and AUS, and days antibiotic treatment were collected and analyzed. AXR and AUS are categorized as ‘Abnormal’ if radiology reports contain findings of bowel wall thickening, pneumatosis, portal venous gas, and/or free air. AXR and AUS are categorized as ‘Equivocal’ if radiology reports contain phrases such as “pneumatosis vs. stool”, “cannot rule out pneumatosis”, “nonspecific gaseous distention” and ‘Normal’ if there are no noted abnormal or equivocal findings in radiology reports.
Conclusions
Kim JH. Role of Abdominal US in Diagnosis of NEC. Clin Perinatol 2019;46:119–27. https://doi.org/10.1016/j.clp.2018.10.006. Rich BS, Dolgin SE. Necrotizing Enterocolitis. Pediatr Rev. 2017;38(12):552-559. doi:10.1542/pir.2017-0002
Treatment Course: Medically managed initially with gut rest and antibiotics based on equivocal AXR findings. Negative AUS resulted in discontinuation of antibiotics and re-initiation of feeds.
Van Druten J, Khashu M, Chan SS, Sharif S, Abdalla H. Abdominal ultrasound should become part of standard care for early diagnosis and management of necrotising enterocolitis: A narrative review. Arch Dis Child Fetal Neonatal Ed. 2019;104:F551–9. https://doi.org/10.1136/archdischild-2018-316263.