Septic arthritis of the lumbar facet joint presenting as spontaneous bacterial peritonitis: a rare case requiring surgical intervention

Bacterial and Viral Infectious Disease of the Spine

Spinal infections are a diverse group of diseases affecting different compartments of the spine with variable clinical and imaging presentations. Diagnosis of spinal infections is based on a combination of clinical features, laboratory markers, and imaging studies. Imaging plays a pivotal role in the diagnosis and management of spinal infections. The characteristic imaging manifestations of bacterial and viral infections in the spine are discussed with key teaching points emphasized.

Septic Arthritis of the Spinal Facet Joint: Review of 117 Cases

Background

Septic arthritis of the spinal facet joints is increasingly recognized in the era of magnetic resonance imaging, but its epidemiology, clinical features, management, and prognosis are ill-defined.

Methods

We review 101 previously published cases and report 16 cases occurring at our institutions between 2006 and 2018.

Results

Most patients presented with fever (60%) and back or neck pain (86%). Radiation into the hip, buttock, or limb was present in 34%. The lumbosacral vertebral segments were involved in 78% of cases. Most cases (64%) were due to Staphylococcus aureus. Bacteremia was present in 66% and paraspinal muscle abscesses in 54%. While epidural abscesses were present in 56%, neurologic complications were seen in only 9%, likely because most abscesses arose below the conus medullaris. Neurologic complications were more common with cervical or thoracic involvement than lumbosacral (32% vs 2%, P < .0001). Extraspinal infection, such as endocarditis, was identified in only 22% of cases. An overall 98% of patients survived, with only 5% having neurologic sequelae.

Conclusions

Septic arthritis of the facet joint is a distinct clinical syndrome typically involving the lumbar spine and is frequently associated with bacteremia, posterior epidural abscesses, and paraspinal pyomyositis. Neurologic outcomes are usually good with medical management alone.

Imaging assessment of spine infection

This article comprehensively reviews current imaging concepts in spinal infection with primary focus on infectious spondylodiscitis (IS) as well as the less common entity of facet joint septic arthritis (FSA). This review encompasses the multimodality imaging appearances (radiographs, CT, MRI, and nuclear imaging) of spinal infection-both at initial presentation and during treatment-to aid the radiologist in guiding diagnosis and successful management. We discuss the pathophysiology of spinal infection in various patient populations (including the non-instrumented and postoperative spine) as well as the role of imaging-guided biopsy. We also highlight several non-infectious entities that can mimic IS (both clinically and radiologically) that should be considered during image interpretation to avoid misdiagnosis. These potential mimics include the following: Modic type 1 degenerative changes, acute Schmorl's node, neuropathic spondyloarthropathy, radiation osteitis, and inflammatory spondyloarthropathy (SAPHO syndrome).

Differential Diagnosis of Facet Joint Disorders

Spinal pain due to facet joint disease is difficult to diagnose since the clinical history and physical examination findings are usually nonspecific. Facet joint disorders have a wide range of causes and, because of the potential for chronic back pain and disability, an accurate diagnosis is essential. The most frequent cause of pain in facet joints is osteoarthritis, which can be assessed at radiography, CT, or MRI. Ganglion and synovial cysts of the facet joints can cause compressive symptoms of adjacent structures, especially radiculopathy, lower back pain, and sensory or motor deficits. In ankylosing spondylitis, imaging findings of the facet joints are useful not only for diagnosis but also for monitoring structural changes. In septic arthritis of the facet joints, an early diagnosis at MRI is essential. Gout and metabolic diseases are best evaluated at dual-energy CT, which allows the depiction of crystals. Traumatic dislocations of facet joints are usually unstable injuries that require internal reduction, fixation, and fusion and can be well assessed at CT with three-dimensional reconstructions. Facet joint neoplasms like osteoid osteoma, plasmacytoma, tenosynovial giant cell tumor, and osteochondroma are best evaluated at CT or MRI. The authors provide an overview of key imaging features of the most common facet joint disorders along with anatomic tips and illustrative cases. Acknowledging key imaging findings for the differential diagnosis of facet joint disorders plays a crucial role in the diagnostic accuracy and proper treatment approach for such entities. Online supplemental material is available for this article. ^©RSNA, 2021.

Spinal cord disorder due to spinal epidural abscess secondary to thoracic facet joint septic arthritis-a rare case with a surprising evolution

INTRODUCTION

Septic arthritis of a facet joint (SAFJ) is a relatively rare medical entity and the lumbar segment is its most frequent location. Although unusual, a spinal epidural abscess (SEA) can occur as a complication of SAFJ and possibly damage the spinal cord.

CASE PRESENTATION

A 53-year-old woman presented with acute right dorsal pain, fever, loss of sphincters control, and paraparesis without causal factor. Forty-eight hours after the symptoms started, imaging revealed a thoracic posterior epidural collection causing compression of the spinal cord and features suggestive of septic arthritis of right T5-T6 facet joint. She underwent an urgent laminectomy and drainage of the abscess. Both blood and abscess cultures isolated Staphylococcus aureus. A diagnosis of complete paraplegia grade A of the ASIA (American Spinal Injury Association) Impairment Scale (AIS) with neurologic level T10 was made 5 days after surgery. She took 3 months of an intensive rehabilitation program at our Physical and Rehabilitation Medicine ward. With an unexpected favorable evolution, both neurological and functional, she was discharged with an incomplete paraplegia AIS D and functionally independent in all tasks.

DISCUSSION

This case reveals an infrequent medical condition on a rarely affected spinal segment. An early diagnosis and proper treatment of SAFJ and SEA are of major importance to avoid severe related consequences. Patients with spinal cord injury with severe neurological deficits due to these conditions greatly benefit from an interdisciplinary rehabilitation program to improve neuromotor and functional status.