Lung ultrasound description of a newborn with bronchial atresia: A case report

Introduction

Congenital pulmonary malformations are a heterogeneous group of embryological alterations at different stages of lung development. The most common are congenital pulmonary airway malformations (CPAM). ¹

The gold standard examination for congenital pulmonary malformations is computed tomography (CT), with excellent correlation with prenatal ultrasound findings ¹ but a high cost–benefit ratio due to its potential side effects. ²

With the popularisation of the use of prenatal ultrasounds, CPAM diagnosis has increased to an estimated incidence of 1/25,000 live births and is still increasing. ³ Therefore, the early visualisation of these abnormalities and the implementation of a specific protocol for their detection in neonatal intensive care units (NICU) would lead to a change in the traditional medical diagnosis protocol. ³

Lung ultrasound (LUS) is already a very useful tool in NICUs, thanks to its absence of radiation emission, portability to the patient’s bedside and the possibility of being performed, as well as interpreted, during the first hours of life. ⁴ Along with this, it provides great clinical value for the differential diagnosis of neonatal respiratory diseases, ⁵ showing signs that can be used as predictors of respiratory status and the need for respiratory support, ⁶ or detecting early progression towards bronchopulmonary dysplasia. ⁷ Finally, it can also be used as a tool for monitoring short- to medium-term complications or the degree of response to therapies, such as the use of diuretics and their impact on the preterm newborn. ²

In the available literature, there are only four articles^2,8,9 whose data describe the use of LUS with different congenital pulmonary malformations, with only 10 cases described in them, none of which relate to bronchial atresia. We present the first described case of bronchial atresia with LUS findings since birth.

Case report

The case is a female term newborn with a gestational age of 38 weeks and a birth weight of 2.915 kg. Prenatal follow-up for CPAM suspicion in the left lung, together with mediastinal shift to the right from week 22 and the posterior disappearance of these images at week 28, was done. There were no other complications during pregnancy. Maternal serologies for toxoplasma, syphilis, human immunodeficiency virus, cytomegalovirus, rubella and herpes simplex virus were negative. She was born by emergency caesarean section due to breech presentation without requiring resuscitation. Apgar scores were 9 and 10 at 1 and 5 minutes, respectively. She was admitted at birth, with a normal physical examination, without signs of respiratory distress. Atelectasis of the left upper lobe was seen via chest radiography (X-ray) (see Figure 1). LUS on the second day of life (see Figure 2) showed a normal profile, with a consolidation located in the left posterosuperior field with air bronchogram and with no pleural effusion. In subsequent ultrasound examinations (see Figure 3), we observed an interstitial pattern compatible with progressive aeration of the area, which remained the same until 1 month of life. Echocardiography, as well as abdominal ultrasound, did not show additional malformations. The CT scan performed at 6 months of age (see Figure 4) showed hyperlucency and increased volume in the left upper lobe, with slight hypovascularisation, accompanied by a paramediastinal subsegmental atelectasis. The left upper lobe was not seen due to a hypodense image at the hilum. These findings were compatible with bronchial atresia, subsequently confirmed by fiberoptic bronchoscopy. At 18 months of age, a scheduled surgical intervention was performed without incidents.

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Figure 1.

Portable chest X-ray at admission which showed left upper lobe atelectasis.

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Figure 2.

Lung ultrasound on the first day of life. Arrows represent findings suggestive of consolidation with an air bronchogram. Loss of continuity is also seen in the pleural line.

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Figure 3.

Lung ultrasound on the third day of life. Findings are similar to the rest of serial ultrasounds up to 1 month of life. An alveolar-interstitial infiltrate is seen, which is indicated by yellow asterisk.

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Figure 4.

CT image shows the lesion in the left lung, with paramediastinal subsegmental atelectasis (yellow square) and signs of air trapping.

Discussion

We have described the case of a newborn with bronchial atresia in which the use of LUS helped to reach the final diagnosis of the lesion and locate its existence despite the fact that at birth, the X-ray suggested findings compatible with an atelectasis.

In the previous review in relation to CPAM published by Wong et al., ⁸ it was found that the prevalence is higher than previously described. It is clear that there are more malformations diagnosed due to the use of better instruments for prenatal ultrasonography, thus presenting new controversies in their postnatal management, whether surgical or expectant, as well as the exact risk of malignancy associated with them.

The first LUS findings described by Yousef et al. ² showed that ultrasonography does not allow for the exact measurement of lung lesions with a specific pattern, but its precision was similar to that of CT. LUS is an easy tool to apply and not very dependent on the technique.

In the clinical cases published by Quercia et al., ⁹ the authors showed how the prenatal ultrasound was able to diagnose six of the seven cases presented with pulmonary malformations. In all cases, postnatal ultrasonographic findings showed significant correlation with CT, proving to be a safe and effective technique that avoids radiation as much as possible. Therefore, it will allow us to speed up the diagnosis with a lower rate of radiation, reducing the harmful effects in a highly sensitive population. The overall survival rate of the affected patients stands out, as well as their early discharge from the unit and satisfactory subsequent follow-up.

The case series presented by Merli et al. ³ confirmed the usefulness of ultrasonography and its pre- and postnatal differences, as well as the limitations of radiographies. In addition, it has the potential to closely monitor the patient while waiting until the pre-surgical CT is performed, which is mandatory to achieve the best surgical plan, allowing clinical anticipation.

It is up to us to recognise the usefulness and importance of serial LUS as a screening method in neonatal units, which can be postulated as a prolongation of the clinical signs.

Conclusion

We present the first case of bronchial atresia diagnosed by LUS, thus adding new images to the very scarce literature currently available.

In this sense, we want to emphasise the importance of the use of LUS in newborns with prenatal suspicion of pulmonary airway congenital malformations although its disappearance prior to childbirth is evidenced. We enhance the value of ultrasound because LUS allows early assessment of injury even before aeration rest of the lung parenchyma which makes the examination more hard.