Prevertebral thoracic abscess in neonate- a previously unknown cause of respiratory failure in neonates: a case report

INTRODUCTION

Prevertebral space is a potential space between prevertebral fascia and vertebral bodies; it extends superiorly from the base of the skull to the coccyx inferiorly.¹ Hematogenous spread and cervical spine infection are the well-documented causes of prevertebral abscess in the literature.^2-4

The diagnosis of prevertebral abscess is challenging even in adults, as it requires a high index of suspicion because of its wide spectrum of presentation. Adult literature has well documented the untreated prevertebral abscess leading to paralysis in 4%-22% of patients.^5,6

While prevertebral abscess cases have been reported in adults, there have been no reported cases of prevertebral thoracic abscess in neonates to date. We present a case of a prevertebral thoracic abscess as a rare cause of airway obstruction in neonates.

CASE REPORT

An out-born term girl neonate born to 32 years old primigravida mother out of a non-consanguineous marriage by emergency lower segment caesarean section (indication-cord around neck). The mother had received regular antenatal care, had an uncomplicated pregnancy with no history of sexually transmitted infections, and all the antenatal screening tests were negative. The baby suffered no medical or traumatic injuries after birth. Baby’s birth weight was 3 kg (50^th percentile), and Apgar scores at 1 min and 5 min were 7 and 9, respectively. There were no dysmorphic features. Breast-feeding was initiated within two hours of life, and the baby was discharged home at 72 hours of age. Baby stayed with her parents and paternal grandparents, was apparently well on exclusive breast feeds, and was taken for two routine follow-ups. On day 17 of life, mother observed that baby had suddenly become dull, had poor feeding, and noisy difficult breathing. She was admitted to a nearby hospital on suspicion of sepsis with possible laryngomalacia. Presenting symptoms were fever (38°C), with suprasternal, intercostal, and subcostal retractions with Downe’s score of 4/10. Chest X-ray showing clear lung fields, positive C-reactive protein, a total count of 16500/mm³, and blood culture showing MRSA, was started on intravenous vancomycin. In view of worsening respiratory distress, she was transferred to our neonatal ICU on CPAP (continuous positive airway pressure) on day 20 of life.

Management and outcome

On admission to our NICU, the baby weight was 3.2 kg, and she was sick-looking, with fever, tachypnea, and tachycardia, with severe suprasternal, intercostal and subcostal chest retractions (Downe’s score of 7/10). Blood pressure was 88/60/69 mmHg and oxygen saturation (SpO₂) was 74% in room air, which improved to 86% with free flow oxygen. Initial ABG showed pH=7.11, pO₂=57.9 mmHg, pCo₂=155.0 mmHg, HCO₃=47.9 meq/l, BE 9.0, and oxygenation index (OI) of 12. Chest X-ray showed bilateral haziness of lung fields (Figure 1).

The baby was intubated without difficulty using a video-laryngoscope which showed apparently normal upper airway. ET tube position was clinically and radiologically confirmed. Baby was put on synchronised intermittent mandatory ventilation mode, on which there was improvement clinically, and on blood gas pH=7.378, pO₂=93 mmHg, pCO₂=63 mmHg, HCO₃=36 meq/l, BE=8.7, saturations, and OI reduced to 3. Over next few days, baby had frequent desaturations on the ventilator, sometimes with bradycardia. All possible causes were looked into. Twice in the disease course, because of persistent desaturations with increased oxygen requirements, respiratory acidosis, and an increased oxygenation index (15-17), the baby was given High Frequency Oscillatory Ventilation (4 days in total). Two failed extubation attempts with immediate re-intubation. A repeat blood culture confirmed MRSA, and intravenous vancomycin was continued. A search was done for a potential source of infection that could be controlled, but no sources could be identified. Echocardiography was normal, with no need for any inotropic support. After ruling out all common causes of respiratory failure, the possibility of airway obstruction distal to the intubated part of the trachea was considered. Bronchoscopy (Figure 2) revealed anterio-posterior collapse in the trachea, with the possibility of tracheomalacia or an extramural compressing lesion like vascular rings, slings, or a tumour. A chest CT scan (Figure 3) confirmed the presence of a posterior mediastinal prevertebral abscess or mass (4.6×3.6×1.9 cm) extending from C4-5 level to T6-7 vertebral level, pressing on the trachea from behind, with no direct communication with the trachea or oesophagus, nor any epidural extension. There was segmental consolidation of right upper and bilateral lower lobes.

The pediatric surgery team, via thoracotomy, drained, thick purulent material (25-30 ml), which was positive for MRSA. Post-surgery, baby was clinically better, within 24-hour ventilation requirement came down (Oxygenation index of 2.5) and was extubated to CPAP, and subsequently depronged to room air. The total duration of ventilation needed was 13 days. Post-operatively, on day 4 direct breast feeding was started; on day 5 shifted out of the NICU, Vancomycin was given for a total period of 21 days, and discharged home. On follow-up, baby has been doing well and is clinically stable.

DISCUSSION

Neonatal healthcare providers frequently come across cases of respiratory distress in newborns. It is crucial to keep prevertebral abscess in mind when considering potential causes of upper airway blockage, particularly if bronchoscopy results indicate narrowing of the tracheal lumen, as illustrated in our recent case study. Furthermore, key clinical indicators that should prompt clinicians to consider abscesses include fever in neonates, elevated white blood cell count, and inadequate response to intravenous antibiotic treatment.

The other important close differential diagnosis is retropharyngeal abscess, which lies anterior to the prevertebral fascia.⁷ Inflammation can cause a narrowing of the neonatal pharyngeal space, which is not fully developed, leading to potential airway obstruction and even death. Therefore, it is crucial to promptly identify any symptoms related to the airway in order to urgently diagnose and treat neonatal neck abscesses. The preferred diagnostic methods for this condition are CT scans and MRI scans. These imaging techniques provide valuable information to accurately diagnose and effectively manage neonatal neck abscesses.

Though prevertebral abscess is reported in adults, there was no published report of a case in newborns. In their study, Manmathan et al documented a case of a 61-year-old diabetic patient who exhibited symptoms of a prevertebral abscess, including high grade fever, neck pain, dysphagia, and odynophagia.⁸ However, it is important to note that diagnosing prevertebral abscess in newborns can be challenging for clinicians. Unlike adults, newborns may not display the typical symptoms associated with this condition, making it difficult to identify and diagnose. In line with our case study, Sahoo et al documented a 41-year-old male who exhibited symptoms of low-grade fever, limb weakness, and airway obstruction. While these cases may sensitize neonatologists to the prevertebral abscess, diagnosing it in newborns requires a high level of suspicion.⁹

A study conducted by Jalisi et al focused on a retrospective review of 11 adult patients who were diagnosed with prevertebral abscess.¹⁰ The study highlighted that the most prevalent symptoms observed in this group included neck pain (100%), odynophagia (54%), dysphagia (36%), and neck rigidity (36%). Despite the findings in adult patients, there is a noticeable gap in the literature regarding prevertebral abscess in neonates. This lack of data emphasizes the importance of our case report, which aims to raise awareness within the medical community about the occurrence of prevertebral abscess in neonates. By shedding light on this condition in neonates, our case report serves as a valuable contribution to the existing knowledge on prevertebral abscess. It is crucial for healthcare professionals to be informed about the potential presentation of this condition in neonates in order to ensure timely diagnosis and appropriate management.

Prevertebral abscess is uncommon even in adults compared to other deep neck abscesses.^11-13 Considering this, a very high index of suspicion is required to diagnose in neonates.

CONCLUSION

Airway compression in neonates can be caused by a rare condition known as paravertebral thoracic abscess. This condition, although uncommon, should be taken into consideration when diagnosing the cause of airway compression in neonates, it is crucial to include in the list of potential causes during the differential diagnosis process. It is therefore, important for clinicians to look for unusual causes, even in previously healthy neonates with no apparent antecedent risk factors, and especially in cases requiring prolonged ventilation with difficult extubation.

ACKNOWLEDGEMENTS

The authors would like to thank parents for giving the consent to report the case.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

REFERENCES

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