Retropharyngeal Abscess With Mediastinal Extension: A Case Series and Review of the Literature

Abstract

Deep neck infections are common in infants and occur in several anatomic subsites including the retropharyngeal space. Retropharyngeal abscesses are significant given their propensity for mediastinal extension and can have life-threatening sequelae. We present 3 cases of retropharyngeal abscess with mediastinal extension in infants. In one case, an incompletely vaccinated 10-month-old boy presented with cough, rhinorrhea, and fever. Despite antibiotic treatment, he developed Horner’s syndrome and hypoxia. A computed tomography (CT) scan showed a C1-T7 retropharyngeal abscess. He underwent transoral incision and drainage and recovered fully. In another case, a 12-month old infant presented with 8 days of fever and neck pain. A CT scan showed a retropharyngeal collection extending to the mediastinum and right hemithorax. Transoral incision and drainage and video-assisted thoracoscopic surgery thoracotomy were performed for abscess drainage. He recovered fully with antibiotics. In the third case, an 8-month-old boy presented to the emergency room following several days of fever, lethargy, and decreased neck range of motion. A CT scan showed a large retropharyngeal abscess that required both transoral and transcervical drainage. His case was complicated by septic shock, yet the patient eventually made a full recovery.

Introduction

Deep neck space infections (DNIs) are life-threatening conditions that are significantly more common in infants and young children than in adult populations. Despite their serious nature, diagnosis can be difficult and is often delayed, especially in infants and toddlers who cannot accurately describe their symptoms. Prompt diagnosis and treatment is essential to prevent airway and life-threatening complications of deep neck infections, one of which is descending mediastinitis. ¹ While the mortality rate of descending mediastinitis is considerably lower in children than in adults, mediastinal infections require aggressive management that should not be delayed. ²

Several studies have suggested that pediatric DNIs most often present following a viral upper respiratory infection and its associated lymphadenitis, which can progress to phlegmon and eventual abscess. DNIs can occur in several anatomic subsites: peritonsillar, parapharyngeal, and retropharyngeal, the latter of which is located between the posterior pharyngeal wall and the prevertebral fascia and is the subject of this report. Retropharyngeal abscesses are most common in children under 4 years of age owing to lymphatic flow from the oropharynx to the retropharyngeal lymph nodes, which typically atrophy in older children.^1,3 Earlier reports have demonstrated that descending mediastinitis is more common following a retropharyngeal abscess than other deep neck infections, and the relationship of the 2 conditions is well established anatomically. We will report 3 cases of retropharyngeal abscess with mediastinal extension in infants 1 year of age and under.

Case 1

The patient is a 10-month-old boy who was in his usual state of health until he developed fever, rhinorrhea, lethargy, and neck stiffness at home. Prior to this episode, he was otherwise healthy with no history of hospitalizations or medical problems; however, he was not up to date on vaccines. He was transferred to our institution where he was found to have a leukocytosis with a white blood cell count of 17,000. A lumbar puncture was negative for meningitis; however, blood cultures returned positive for methicillin-resistant Staphylococcus aureus (MRSA). He immediately began treatment with vancomycin and ceftriaxone for bacteremia.

On hospital day 6, his respiratory status considerably worsened with an increasing oxygen requirement. A chest X-ray was notable for a new right upper lobe infiltrate. The patient was noted to have unilateral right Horner’s syndrome. A computed tomography (CT) scan of the neck and chest was ordered which showed a large retropharyngeal abscess extending from C1 to T7, measuring 8.3 × 1.4 × 2 cm. In addition, there was a small 1.5 × 1.2 cm right paratracheal fluid collection.

At this point, the otolaryngology team was consulted and the decision was made to proceed with urgent surgical management. Significant edema was noted over the posterior pharyngeal wall and an incision was made transorally over this area. A tonsil clamp was used to explore the abscess cavity with return of copious pus. Given the mediastinal extension on CT scan, a flexible suction catheter was slowly advanced distally and more purulent material was drained. A red rubber catheter was placed through the patient’s right nare and fed into the pharyngeal incision as a drain; this was sutured loosely to the pharyngeal wall.

On postoperative day 2, the patient was extubated and the drain was removed. He remained afebrile with negative blood cultures and was placed on oral linezolid. Cultures sent from the operating room were sterile, likely due to his prolonged course of broad-spectrum antibiotics prior to surgical drainage. Of note, an immunodeficiency workup was negative.

Case 2

The patient is a 12-month-old boy who presented to his pediatrician with an 8-day history of upper respiratory infection. Despite intramuscular ceftriaxone, he continued to have fever and developed decreased neck range of motion. At this point, he was sent to a local emergency department, where a lateral neck X-ray showed retropharyngeal thickening.

On presentation at the children’s hospital, he was noted to be lethargic with drooling and a limited neck range of motion. He was febrile at 101.8°, and had a leukocytosis (WBC: 25,000). A CT scan of the neck and chest showed a large retropharyngeal abscess that was well defined throughout the retropharyngeal space with extension inferiorly into the mediastinum. There was a significant contiguous dependent collection in the right mediastinum.

The child was then taken urgently to the operating room by the otolaryngology and thoracic surgery teams. The otolaryngologist noted doughy pharyngeal mucosa and was able to enter the retropharyngeal space transorally. Copious dark serous fluid was drained and residual dried, purulent material was evacuated with irrigation and suction. Next, the thoracic surgeon performed a video-assisted thoracoscopic surgery thoracotomy. Dense intrathoracic adhesions were noted as well as a large, fluctuant mediastinal mass which contained similar dark serous fluid. A large pocket of purulent debris was irrigated and debrided. A chest tube was left in the place.

Over the next several days, the patient recovered well in the pediatric intensive care unit (ICU). His intraoperative cultures grew MRSA which was sensitive to clindamycin. His intravenous antibiotics were narrowed and he defervesced on intravenous clindamycin. He was subsequently discharged on oral antibiotics 2 weeks postoperatively.

Case 3

The patient is an 8-month-old boy who presented to the emergency department with a 2-day history of high fever, poor feeding, and lethargy. On arrival to the emergency department, he was noted to have a fever of 105° and a leukocytosis with a white blood cell count of 14,000. He was admitted to the ICU and immediately started on empiric intravenous vancomycin and ceftriaxone.

Upon admission to the ICU, he was noted to be lethargic and drooling with bilateral neck swelling, left neck erythema, and decreased neck range of motion. Therefore, a CT scan of the neck with contrast was obtained which demonstrated a large retropharyngeal abscess with extension into the superior mediastinum (Figure 1). He became acutely hypotensive requiring fluid resuscitation and vasopressor support. He was then taken urgently to the operating room for intubation and transoral incision and drainage. Needle aspiration in the posterior pharyngeal wall yielded copious purulent and thick exudative material. An incision was made and extended inferiorly, followed by blunt dissection posterior to the larynx. A drain was sutured in place through the incision to prevent recollection.

Figure 1.

Sagittal CT scan of the neck demonstrating a retropharyngeal abscess extending toward the mediastinum.

Over the next several days, the patient’s condition remained critical requiring vasopressor support and broad-spectrum antibiotics. He remained afebrile until postoperative day 4, when he developed spiking fever and an increased white blood cell count of 31,000. Repeat CT scans of the neck and chest were obtained which demonstrated a slight decrease in size of the retropharyngeal abscess on the left, but showed further extension of the abscess inferiorly into the mediastinum adjacent to the aortic arch (Figure 2).

Figure 2.

The retropharyngeal abscess is seen adjacent to the great vessels in the mediastinum.

The child was then taken urgently to the operating room with both the otolaryngology and thoracic surgery teams. Both transoral and transcervical approach for incision and drainage were performed, with thick, purulent exudate expressed. Next, thoracic surgery bluntly dissected inferiorly to the mediastinum to release additional purulent material.

His original blood and intraoperative cultures grew MRSA, and he was kept on intravenous vancomycin and rifampin for the following 2 weeks. He was extubated on postoperative day 16 and discharged home on hospital day 25 on vancomycin to complete a 6-week course.

Discussion

Our 3 cases demonstrate the critical importance of timely diagnosis of pediatric DNIs to initiate aggressive management. A retrospective review by Adil et al ⁴ noted an incidence of 4.6 per 100,000 of pediatric deep neck infections, with a complication rate of 4.8%. ⁴ Of note, this accounted for greater than 75 million dollars in hospital charges in 2009. Retropharyngeal abscesses in particular are increasing in incidence faster than all other types of deep neck infections. ⁵ Therefore, pediatric neck infections must be recognized as a significant disease burden and should be investigated in any pediatric infectious workup. ⁴

All 3 patients in this report had retropharyngeal abscesses that progressed to descending mediastinitis. In a recently published case series, Wilson et al analyzed 19 cases of descending mediastinitis and found retropharyngeal abscess to be the abscess site of origin in 16 of those cases. All patients in their case series were under 18 months old, further demonstrating descending mediastinitis from deep neck infections to be a disease of infants and toddlers.^6,7 Awareness of the potential for mediastinal extension is critical in management of retropharyngeal abscesses so that correct imaging studies are ordered and appropriate consultants are involved.

Also notable in the Wilson review was the fact that MRSA was isolated in 13 of 14 positive patient cultures. ⁷ In the post-pneumococcal vaccine era, infections with Streptococcus pneumoniae have become less prevalent and concordantly, S. aureus has become more virulent. ⁸ Shah et al also found S. aureus to be the causative agent in 4 cases of descending mediastinitis from a deep neck infection in a 2009 review. Two of 4 patients in their report had cultures positive for MRSA, while the other 2 patients grew methicillin-sensitive Staphylococcus aureus. ² A case series by Naidu et al had similar findings, with 4 cases of MRSA DNIs in children younger than 2 years old. ⁹

From our 3 patients and a review of the literature, it is clear that practitioners should maintain a high index of suspicion for pediatric DNIs in the infant with fever and leukocytosis. Imaging should be ordered when warranted and patients should be followed with serial images if they are being treated conservatively with antibiotics. In the series by Shah et al, 4 infants treated with antibiotics for retropharyngeal phlegmons developed abscesses that progressed to mediastinitis and required surgical drainage. Three of 4 required thoracoscopic surgery for mediastinal abscesses. ² Our patient in case 1 was able to be successfully managed surgically with transoral drainage alone and made a full recovery, while our patients in case 2 and case 3 required both transoral and transthoracic drainage.

In cases of retropharyngeal abscess, prompt diagnosis, appropriate imaging, aggressive surgical management, and antibiotic coverage for MRSA are all imperative. Aggressive management has kept the mortality rate of pediatric descending mediastinitis under 10% as cited in several studies. Practitioners should be exceptionally vigilant in treating patients who are under 18 months of age ⁵ or are unvaccinated, as our cases illustrate.