A Curious Case of Recurrent Respiratory Compromise in the NICU

Neonatal respiratory distress is a common presentation in preterm infants, often attributed to complications of prematurity. However, when symptoms recur after apparent improvement or deviate from the expected clinical course, a broader differential must be considered. This case highlights a diagnostic and management challenge in a preterm infant who developed progressive respiratory insufficiency despite appropriate supportive care. Through a multidisciplinary investigation, an unexpected etiology was uncovered, prompting both medical and surgical interventions. This case report was reviewed by the institutional Health Research Ethics Board (REB) and was exempt from review. A male infant was delivered at 32 weeks completed gestation at a level 2 rural neonatal intensive care unit (NICU) center via emergency cesarean section due to fetal heart rate abnormalities. Maternal serologies and antenatal ultrasounds showed no abnormalities. One dose of betamethasone was given before delivery. Apgar scores at birth were 5, 6, and 9 at 1, 5, and 10 min. His birth weight was 2108 g. He was admitted to the NICU for Continuous Positive Airway Pressure (CPAP) respiratory support and ongoing care related to prematurity. He appeared non-dysmorphic and appropriately developed for his gestation age with a normal physical examination. A partial septic work up (PSWU) was completed at birth and antibiotics were given for 4 days then discontinued based on negative cultures and lack of infectious symptoms. An initial X-ray at birth for umbilical venous catheter (UVC) line placement showed mild bilateral hazy opacities and no consolidation within the lungs (Figure 1). He was gradually weaned from CPAP to room air by Day 5 of life. He tolerated feeds well. By Day 12 of life, tachycardia and tachypnea requiring respiratory support recurred. His chest X-ray showed an elevated left hemidiaphragm and worsening bilateral lower hazy opacities with an area of lucency in the lower left hemithorax (Figure 2). A PSWU was completed with a normal white cell count, low C-reactive protein (CRP) and a negative blood culture and respiratory pathogens panel (RPP). An infant born at 32 weeks gestation developed respiratory distress at Day 12 of life after being weaned off CPAP several days prior. A repeat PSWU showed a normal white blood cell count, negative blood cultures, and no clinical signs of infection. A chest X-ray showed bilateral lower lung field opacities with an area of lucency in the left lower lung field. What is most likely going on with this patient? (leading and differential diagnosis) What would you do next and why? Listen to the Podcast S1 to hear the consortium's decision-making process. Recurrent tachypnea and respiratory distress on Day 12 of life was treated with CPAP after which the tachypnea and tachycardia improved. A follow up chest X-ray 12 h after CPAP initiation showed persistent elevation of left diaphragm with a round lucency in the lung. Two days after restarting CPAP, the team attempted to wean pressures but the baby did not tolerate this, with increased tachypnea. After another 2 weeks of support, he was successfully weaned to room air. During this time, he had a normal head ultrasound and echocardiogram. A chest ultrasound was non-diagnostic for eventration while on CPAP. A chest CT (Figure 3), conducted at the peripheral hospital, was reported to show a possible left posterior diaphragm eventration or hernia and a right posterior hemithorax lesion separate from the liver. An infant born at 32 weeks gestation presented with respiratory distress on Day 12 of life, with a history of requiring CPAP support from birth to Day 5 of life. A repeat PSWU showed no markers suggestive of infection A chest X-ray showed persistent elevation of left hemidiaphragm and a CT showed possible left eventration and a right posterior hemithorax lesion. What is the best modality for diagnosis of diaphragmatic eventration (DE)? What would you do next and why? Listen to the Podcast S2 to hear the consortium's decision-making process. The baby was transferred to a tertiary care center and was seen by General Surgery, Genetics and Pediatric Pulmonology at 1 month old (36 completed weeks corrected gestational age) for further investigation and management. At that time, he had received no respiratory support for several days. An MRI of his thorax and abdomen (Figure 4) showed bilateral posterior DE with associated near-complete collapse of bilateral lower lobes of the lungs. Of note, there was elevation of his abdominal contents including kidneys, stomach, and bowel being present in his posterior thorax. Although the initial CT report did not identify a thoracic mass, retrospective review suggested that the right-sided lesion was most consistent with a malpositioned right kidney. This was confirmed on MRI in subsequent imaging. There was no evidence of a diaphragmatic hernia on MRI. Respiratory support was re-initiated based on intermittent respiratory distress, worsening respiratory acidosis on blood gas analysis and the MRI findings suggesting persistent bilateral lower lobe atelectasis. He was switched from oral to continuous nasojejunal (NJ) feeds given his higher risk of aspiration from the combination of elevated bowel and persistent work of breathing. Other investigations included Upper Gastrointestinal Series (UGI) which ruled out malrotation. Genetic investigations were also sent including comparative genomic hybridization and Whole Exome Sequencing (WES), which did not identify any specific known genetic etiology. This Ex-32-week infant is now approaching term corrected gestational age. His symptoms have now been diagnosed as bilateral eventration with persistent atelectasis of the lower lobes of the lungs bilaterally. He has ongoing intermittent respiratory support needs with suboptimal growth and is at risk of aspiration. What intervention(s) should be considered? What are the considerations for the timing of surgical repair and associated risks? Listen to the Podcast S3 to hear the consortium's decision-making process. Based on his respiratory insufficiency and risk of long-term complications secondary to persistent atelectasis, aspiration risk as well as poor interval growth, the team decided for surgical repair of his DE. He was intubated pre-operatively and underwent bilateral plication via laparotomy and abdominal wall closure with mesh insertion at 39 + 6 weeks corrected gestation age. A chevron incision was made to access the abdominal cavity, revealing a left hemidiaphragm with a muscular anterior two-thirds and a thin membranous posterior third, along with the left kidney and large bowel occupying the thoraco-abdominal area underneath the intact diaphragm. The diaphragm was flattened by a series of U-stitches to plicate it, and the kidney was repositioned down further in the abdomen. The right side revealed a similar issue with the right kidney and liver in the thoraco-abdomen below intact diaphragm; both were reduced to the proper abdominal cavity. Both sides of the diaphragm were successfully plicated, resulting in a stable, flat position. Loss of abdominal domain was noted after repositioning the liver, kidneys, and bowel. A Gore-Tex DualMesh was used for abdominal wall reconstruction to prevent abdominal compartment syndrome. The infant tolerated the procedure well and was sent back to the NICU intubated with minimal blood loss. His postoperative course was complicated by suspected necrotizing enterocolitis (NEC) on Post-operative Day (POD) 6, which presented as abdominal distention and suspected pneumatosis on X-ray. During that time, he received parenteral nutrition and was treated with antibiotics for 7 days. His abdominal distention improved and he successfully transitioned to full enteral feeds without difficulty following treatment. He was extubated to non-invasive respiratory support on POD 10 and gradually weaned to room air by POD 18. He was discharged from the NICU on room air and tolerating full oral feeds at 73 days of age. Since being discharged, he continues to grow well and meet his developmental milestones with no recurrence of symptoms. The diaphragm is the primary muscle used during inspiration. It acts as a barrier between the thoracic and abdominal cavity and is innervated by the phrenic nerve. DE is a uncommon condition where there is an abnormal elevation of the diaphragm with maintained continuity and attachments to the costal margin. Bilateral DE is a rare diagnosis with a guarded prognosis due to both diaphragms being affected. Presentation is variable from asymptomatic incidental findings on X-ray to respiratory distress. In our case, this preterm infant initially presented with respiratory distress that was managed supportively which was thought to be related to Transient Tachypnea of the Newborn (TTN) or Respiratory Distress Syndrome. (RDS) Early imaging had findings of elevated left hemidiaphragm but this was not initially recognized as part of an underlying structural anomaly. In addition to this, right sided eventrations are also not as easily appreciated in imaging due to the presence of the liver [1]. It was only after the persistence and progression of symptoms that further imaging was pursued, ultimately leading to the diagnosis of bilateral DE. DE can be congenital due to abnormal development and replacement of the diaphragmatic muscle with fibroelastic tissue [2, 3]. It may also be acquired due to damage to the phrenic nerve [4]. Acquired cases are often secondary to birth trauma or thoracic surgery [4]. In our case, no history or clinical signs of perinatal trauma were noted, supporting a congenital etiology. Congenital DE constitutes only 5% of all diaphragmatic defects including congenital diaphragmatic hernias (CDH) and is usually unilateral with the left side more commonly affected than the right [5]. It also has a higher male predominance [6]. The incidence and prevalence of congenital DE in infants is unknown due to some lesions being clinically silent. Some reports estimate this to be as low as 1 in 10,000 but the overall incidence is likely higher due to the number of unreported cases [7]. DE can also be associated with many disorders and infections. These include spondylocostal dysostosis, Kabuki syndrome, Beckwith-Wiedemann syndrome, Poland syndrome, chromosomal abnormalities (trisomy 18), pulmonary hypoplasia, spinal muscular atrophy, malrotation, and congenital heart disease. Infectious associations include fetal rubella and cytomegalovirus infections [8-11]. In our case, the infant appeared non-dysmorphic and there were no associated findings on any investigation to suggest an associated syndrome or disorder. DE can cause respiratory issues due to reduced lung volume and impaired breathing mechanics. This could lead to atelectasis, pneumonia as well as aspiration and respiratory insufficiency requiring support [3]. Abdominal contents can be displaced into the thoracic cavity, further compromising breathing by compressing the lungs. Complications of eventration can also occur later in life with case reports of volvulus and other issues with malpositioned abdominal contents being the highest risk of morbidity [12, 13]. The diagnosis of DE is usually made postnatally and can be delayed due to the absence of symptoms [14, 15]. Chest X-ray can suggest the diagnosis by showing the elevation of the hemi-diaphragm. Still, it can be challenging to differentiate between DE and CDH due to the similarities in imaging findings. Ultrasound can be used to confirm the findings by demonstrating minimal or paradoxical diaphragmatic movements although this is operator dependent. Another potential confounding factor related to our case is the use of CPAP support which may have limited diaphragmatic motion and obscured imaging features suggestive of eventration. In our case, the final diagnosis was made using MRI which was able to identify DE on both sides of the diaphragm. MRI is considered to be the most accurate modality for characterizing diaphragmatic anatomy, although its use in neonates is limited by access, cost and need for sedation. Fluoroscopy is another modality that can assist with the diagnosis and allows for functional assessment of the diaphragm but it lacks the anatomical resolution detail provided by MRI. With regard to management, the choice between conservative management or surgical repair depends on several factors including the presence or absence of symptoms, adequacy of nutritional intake and growth, the need for respiratory support and the presence of complications such as volvulus or recurrent pneumonia. Surgical management is recommended for symptomatic cases, particularly for bilateral eventration where the risks of complications are higher due to both diaphragms being structurally compromised, with associated higher risk of respiratory failure. There is no standardized approach regarding the timing of surgical repair. Stabilization on non-invasive ventilation before surgery is suggested, although with limited literature support. Earlier intervention may also improve growth and prevent lung injury [3] In our case, surgery was done closer to term as the infant continued to be symptomatic with ongoing tachypnea and bibasilar atelectasis despite interval growth. Complications after abdominal plication of a DE commonly include atelectasis and rarely, abdominal compartment syndrome and splenic injury after mobilization of the left upper quadrant abdominal structures [16, 17]. In our case, he developed findings suggestive of NEC which was managed with bowel rest and antibiotics. Following discharge, he will require routine monitoring and follow-up with a multidisciplinary team including a Pediatrician, Pediatric Pulmonologist and a Pediatric Surgeon given the possibility of relapse or recurrence of eventration. Currently, there are no consensus guidelines for post-operative surveillance. Based on multidisciplinary discussion, we recommended annual follow-up including clinical evaluation and chest imaging to monitor for recurrence of eventration, as symptoms may lag behind radiographic findings. Overall, the prognosis of infants who undergo surgical plication for DE is favorable [15]. The infant is currently doing well, not requiring any respiratory support and growing appropriately. This case is an excellent example of a multidisciplinary collaboration between Neonatology, Pediatric Pulmonology, Radiology, and Pediatric Surgery teams toward the management of a rare condition. Bilateral DE is a rare but important consideration in infants with persistent respiratory distress and unexplained lower lobe opacities on imaging, particularly when common causes of respiratory distress have been ruled out. MRI offers excellent anatomical detail and is often the most definitive modality for confirming the diagnosis, particularly when other imaging is inconclusive. Its use however may be limited by cost, availability and need for sedation in neonates. The timing of repair is not well defined but dependent on the severity of symptoms as well as the size of the baby. Surgical repair should be considered early in symptomatic cases to prevent complications and sequelae of prolonged respiratory insufficiency. Risks of early intervention must be weighed against the potential benefits of delaying surgery to allow the baby time to grow. Bilateral DE can present as an isolated finding or in association with other anomalies and conditions which should be investigated. Follow-up of patients with DE is necessary for possible complications or recurrence of eventration. Abdulaziz Abul: conceptualization, writing – review and editing, writing – original draft, visualization, software. Ioana Bratu: writing – review and editing, software. Michelle Noga: writing – review and editing, software. Anne Hicks: writing – review and editing, conceptualization, software. Matthew Hicks: writing – review and editing, supervision, conceptualization. Case presentation and images used with written consent from the patient's family. The authors declare no conflicts of interest. Data sharing is not applicable to this article as no new data were created or analyzed in this study. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

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