Quadriparesis following fish-bone impaction in the throat

INTRODUCTION

Vertebral osteomyelitis and spinal epidural abscesses (SEAs) are extremely rare complications of retropharyngeal abscess (RPA) and occur by contiguous spread of infection.^[1-3] Although RPA is common in children (4.1/1,00,000 population),^[4] it can happen in adults, particularly in those with immunocompromised states, diabetes, and intravenous drug use^[2-4] and in COVID-19 patients treated with immune modulators to arrest cytokine storms.^[1] In immunocompetent adults, however, trauma to local structures such as the oropharynx^[3] or esophagus^[5] with migration of pathogenic organisms has been implicated as the cause in 60% of cases.^[2,3]

CASE REPORT

A 26-year-old lady had a history of fish-bone impaction in her pyriform fossa (that was removed by an otorhinolaryngologist) 3 weeks ago. She continued to have persistent swallowing difficulty and throat pain, and later developed spiking fever, breathing difficulty, and dysphagia for the last 10 days. She presented to us with progressive weakness of all four limbs of 5 days duration and was bedbound for the past 3 days. She had no pre-existing illness. On examination, she was having spastic lower limbs with Grade 1/5 power in both legs with upgoing plantars and exaggerated deep tendon reflexes. Bilateral grip could not be formed, and upper limb power was Grade 3/5 in the shoulders and elbow flexors. A magnetic resonance imaging (MRI) of the cervical spine showed an epidural abscess (anterior to the cord) from C4 to C7 levels and an RPA extending from C2 to D2 levels. The lesion was showing peripheral enhancement on contrast and had central non-enhancing areas. The C5 and C6 bodies were also enhanced on contrast administration. The disc spaces were intact, and axial views showed that the epidural and prevertebral collections were communicating through the intravertebral foramina on both sides [Figure 1a-d].

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Figure 1:

(a) T2-weighted sagittal magnetic resonance (MR) image showing retropharyngeal abscesses (RPA) extending from C2 to D2 with an epidural abscess causing cord compression and effacement of the anterior cerebrospinal fluid (CSF) column; (b) post contrast sagittal image shows enhancement of the lesion with necrotic non enhancing areas; (c) axial MR images T2 and (d) post contrast T1 images showing the RPA is communicating with the intraspinal abscess through the intervertebral foramina bilaterally; (e) post-operative T2-weighted axial and (f) sagittal images 6 months later showing cord is restored to the midline with CSF all around it and no residual compression; and (g) lateral X-ray of cervical spine showing good bony fusion between C5 and C6 with no malalignment of the cervical spine.

Export to PPT

She underwent an anterior cervical approach, removal of the retropharyngeal and prevertebral pus and granulation tissue, C5-C6 discectomy, and removal of epidural pus with irrigation of the prevertebral space by passing an external ventricular drain cranially and caudally anterior to the dura. Gram stain showed Gram-positive cocci, and the pus culture grew Staphylococcus. ZN (Ziehl-Neelsen) stain for acid-fast bacilli and tuberculosis (TB) polymerase chain reaction gene expert showed no evidence of TB. The granulation tissue sent for histopathology also showed no evidence of any granulomas. The patient was put on Injection Vancomycin immediately after collecting the pus intraoperatively, and this was continued for 2 weeks, after which she was put on Tab Linezolid for a further 4 weeks. She was immobilized with a sternal occipital mandibular immobilizer (SOMI) brace and had an uneventful post-operative recovery. Her power started returning by 2 weeks, and at 3 months follow-up, she was completely normal. X-ray cervical spine and MRI done at 6 months follow-up showed fusion of the C5 and C6 vertebrae and no residual thecal sac or cord compression. The prevertebral space was also normal [Figure 1e-g].

DISCUSSION

RPA develops in the retropharyngeal space that is bounded by the prevertebral fascia posteriorly, buccopharyngeal fascia anteriorly, and the carotid sheaths laterally.^[4,6] The space extends from the base of the skull superiorly to the mediastinum inferiorly.^[4,6] This space contains the lymph nodes of Rouviere that usually regress by the age of 5 years, which is the reason why RPA is more common in the pediatric population rather than in adults.^[3] The space is divided by the alar fascia into the true retropharyngeal space (anteriorly) and the danger space (posteriorly).^[7] Like the buccopharyngeal fascia, the alar fascia laterally attaches to the carotid sheath but posterolaterally extends up to the tip of the transverse processes of the cervical vertebrae.^[7]

A RPA extending backwards to involve the spine may thus either directly breach both the alar and prevertebral fasciae and cause vertebral osteomyelitis along with a secondary epidural abscess (abscess with bony involvement^[8]) or may communicate intraspinally, entering laterally through the intervertebral foramina through the danger space. Imaging in our case showed that both these had occurred.

Irrespective of the route of entry or the organisms, once neurological deficits appear present that the treatment of choice is drainage of the RPA and decompression of the spine as soon as feasible.^[2,4,6] If an epidural abscess is located anteriorly, an anterior approach (as we had done) may enable drainage of both the epidural and RPA.^[4,9] Other authors have advocated a posterior decompressive laminectomy along with an anterior approach to drain the RPA.^[1,10] Fixation of the spine is indicated if there is gross vertebral body destruction with instability. This was not found in our case, and we managed to get satisfactory results by a simple discectomy (that allowed drainage of the epidural pus) and put the patient on a SOMI brace for immobilization in the post-operative period. Follow-up imaging showed good fusion and no malalignment of the spine.

CONCLUSION

RPA causing neurological deficits is rare. The alar fascia helps to contain the abscess in most cases and prevents it from spreading into the contiguous structures. However, if this fascia is breached, SEA and vertebral osteomyelitis may occur and cause cord compression. Early surgery and prolonged antibiotic treatment can ensure good outcomes.