Nocardia facet sepsis, an indicator of immunocompromise: illustrative case

Abstract

BACKGROUND

Septic facet cysts are a rare phenomenon reported in the literature among immunocompromised hosts and may require operative intervention for appropriate source and symptomatic control.

OBSERVATIONS

A 70-year-old male with a past medical history of immunoglobulin A lambda smoldering myeloma degenerative lumbar disease who presented with low back and radicular lower extremity pain was found to have a left L4–5 septic facet cyst with extension to the epidural space. Intraoperative cultures were positive for Nocardia species. Staging workup revealed progression to high-risk-profile multiple myeloma.

LESSONS

Patients with septic facet cysts may require operative intervention for appropriate source control. Nocardia spine infections and septic facet cysts are rare and require investigation of preexisting risk factors and any potential underlying immunocompromise.

https://thejns.org/doi/10.3171/CASE25220

Facet cysts of the lumbar spine are relatively rare lesions, estimated to be identifiable in 0.6%−10% of lumbar spine MRI studies,¹ but they can be a cause of symptomatic nerve compression and can be common findings in patients with degenerative lumbar spine pathology.² They are characterized by synovial herniation with degeneration of the facet joint capsule and commonly occur at the L4–5 level and particularly in sites of more pronounced spondylosis due to synovial hyperplasia.³

Symptomatic facet cysts may be considered for nonoperative management in certain cases,⁴ with previous studies presenting cases of successful management of these cysts with facet steroid injections. However, they may also require operative intervention, in the form of either decompression and fusion or decompression alone.^5,6

These cysts may become infected, a phenomenon that has been reported previously in the literature,⁷ although exceedingly rare, and generally occurring in patients with a particular susceptibility to infection, such as diabetes, immunocompromise, or recent radiotherapy. The pathophysiology of this infection may be similar to those of other synovial joints, as a result of hematogenous seeding, and therefore, like other synovial joint infections, may require open irrigation and debridement to be fully eradicated.

In the following case report, we describe a 70-year-old male with a past medical history of degenerative lumbar disease and known facet cyst who presented with low back and radicular lower extremity pain and was found to have a Nocardia L4–5 septic facet cyst with extension to the epidural space in the setting of acute progression of smoldering to high-risk-profile multiple myeloma following an epidural steroid injection.

Illustrative Case

This is the case of a 70-year-old male with a past medical history of immunoglobulin A (IgA) lambda smoldering myeloma, coronary artery disease, bilateral total hip arthroplasty, bilateral total knee arthroplasty, and lumbar degenerative spinal disease with a known left-sided L4–5 facet cyst (Fig. 1). Of note, the patient had no history of spine surgery but had history of multiple injections.

FIG. 1.

MR image prior to onset of infection, demonstrating synovial facet cyst.

The patient was in his usual state of health when 3 days prior to presentation he underwent left-sided L4–5 epidural steroid injection as well as left sacroiliac joint injection. The patient reportedly experienced 1 day of complete symptom relief but then developed progressive lumbar back pain with radiating pain into his left buttock, left groin, and left lower extremity.

His pain became increasingly severe, prompting presentation to his local emergency department, where he was found to have profound urinary retention with a postvoid residual of 750 mL. C-reactive protein on presentation was 164.7 mg/L, and white blood cell count was 10.2. He was subsequently transferred to our institution for further evaluation and management. The presenting examination was remarkable for diffuse left lower extremity weakness, most notable at the quadriceps (2/5 strength limited by pain) and extensor hallucis longus (3/5 strength). Notably, the patient had a prior ankle fusion, which prevented strength assessment of the tibialis anterior. He underwent MRI, which demonstrated an L4–5 epidural collection measuring 9 mm, and redemonstrated a previously visualized 10-mm synovial facet cyst along the facet joint with mass effect along the thecal sac and new peripheral enhancement compared with prior examinations and suggestive of infection (Fig. 2). The patient was initiated on broad-spectrum antibiotics, and operative intervention in the form of L4–5 decompression, irrigation and debridement, and posterolateral fusion was indicated the day following presentation.

FIG. 2.

A–C: Preoperative MR images demonstrating L4–5 epidural collection and synovial facet cyst.

Right-sided minimally invasive surgery (MIS) was performed using a Wiltse-style approach and paraspinal interval. The L4–5 facet joint was prepared in the standard fashion, and pedicle screws were placed. The facet joints and posterolateral gutter were packed with bone graft. This wound was closed prior to approaching the left side so as not to contaminate this region. A second, now left-sided, MIS approach was carried out down to the L4–5 facet joint. Several areas of loculated purulence, including within the left facet joint, ventral facet cyst, and midline epidural space, were encountered and cultured. A left near-total L4–5 facetectomy was determined to be necessary for adequate debridement and decompression of the facet and epidural space (Fig. 2). This necessitated fusion. There were no perioperative complications.

On postoperative day 2, broad-range polymerase chain reaction testing was positive for Nocardia species, which prompted a PET-CT study as well as CT imaging of the chest, abdomen, and pelvis and CT imaging of the head to evaluate for the primary source, given that Nocardia is exceedingly rare in patients without immunocompromise. No other lesions suspicious for infection were identified; however, CT images of the chest, abdomen, and pelvis were remarkable for diffuse lytic lesions about the axial skeleton as well as a pathological fracture of the left lateral eighth rib. Urine protein electrophoresis and serum protein electrophoresis tests were ordered for evaluation of the status of the patient’s disease. Serological studies revealed an elevated IgA of 3200 with a lambda to kappa free light chain ratio > 300, suggestive of an acute progression of the patient’s disease in the setting of negative surveillance imaging 6 months prior. He was given intravenous immunoglobulin (IVIG) for immune support in the setting of his active infection and multiple myeloma diagnosis.

Postoperatively, the patient experienced ongoing issues with urinary retention, for which the urology department was consulted. They recommended a short course of tamsulosin and clean intermittent catheterization. Postoperative MRI demonstrated appropriate decompression but evidence of arachnoiditis concerning for extension of inflammation versus meningeal involvement of infection (Fig. 3). Bone marrow biopsy was performed that demonstrated high-risk-profile (near tetrapoid clone +1q) multiple myeloma. He additionally was found to have hypercalcemia and significant proteinuria concerning for a high burden of disease. Given this, the decision was made to begin management of his myeloma with daratumumab monotherapy 2 weeks postoperatively despite the proximity to his date of surgery. He remained stable and was discharged on postoperative day 19 on intravenous ceftriaxone and oral double-dose Bactrim.

FIG. 3.

Postoperative standing radiographs and MR image (A) compared with preoperative MR image (B).

At the most recent follow-up 4 months postoperatively, the patient demonstrated complete resolution of his urinary retention following a short course of clean intermittent catheterization. His most recent C-reactive protein and leukocyte count were within normal limits. His erythrocyte sedimentation rate was slowly down trending. He is currently reporting near resolution in his preoperative pain.

Informed Consent

The necessary informed consent was obtained in this study.

Discussion

In this case report, we describe a 70-year-old male with a past medical history of degenerative lumbar disease who presented with fever, low back pain, urinary retention, and radicular lower extremity pain, with imaging findings consistent with an L4–5 septic facet cyst with extension to the epidural space. Notably, the patient had a history of smoldering myeloma and also underwent a left L4–5 epidural steroid injection and sacroiliac joint injection 3 days prior to presentation. The patient was taken to the operating room for decompression, irrigation and debridement, and unilateral posterolateral fusion. Intraoperative samples were positive for Nocardia species, and full-body staging workup was undertaken to identify potential distant sites of infection. As a result of this workup, the patient was found to have progression of his smoldering myeloma to active multiple myeloma characterized by numerous lytic skeletal lesions and a pathological rib fracture.

Observations

This case highlights several important factors with regard to evaluation and management of patients with similar presentations. First, this patient presented following a relatively benign procedure, epidural steroid injection. While a causal relationship cannot be drawn as to whether this injection was the source of the patient’s seeding of his infection, it is notable that he developed a clinically significant infection in a short time frame following injection.

Second, Nocardia is a rare⁸ anerobic actinomycete, which is most commonly a cause of pulmonary infections but also cutaneous infections.⁹ Usually, cutaneous infections are caused by the inoculation of traumatic skin lesions; however, once the microbe seeds the bloodstream, whether symptomatic or asymptomatic, it is often implicated in other infections through hematogenous spread.⁹ Most commonly individuals with cell-mediated immunodeficiency are susceptible to disseminated nocardiosis. Of note, while this patient’s intraoperative samples helped to identify the causative organism expediently, his clinical course highlights the importance of early evaluation for potential etiologies for immune compromise in patients with nocardiosis. In this patient, identifying progression of his myeloma was crucial for prompt administration of IVIG for humoral immune support, which has primarily been studied as a prophylactic agent for infection prevention associated with reduction in the risk of severe infection in patients with chronic lymphocytic leukemia or multiple myeloma versus control in some studies.¹⁰

Additionally, progression of multiple myeloma may present with findings similar to spine infections on imaging. In this patient, intraoperatively a significant infectious burden and clear locules of purulence were encountered. Therefore, it is important to consider both oncological and infectious etiologies when directing evaluation and management of such patients.

Lessons

Overall, this case is unique in its presentation, microbial species,^11–13 and the confounding factors in the patient’s presentation. This patient’s course highlights the need for prompt intervention in patients with facet cysts that progress to a septic process. Furthermore, this case highlights the need for a high index of suspicion for recurrent or de novo underlying immunocompromise in patients diagnosed with nocardiasis in order to direct appropriate therapy for immune support as well as for treatment of underlying disease.

Disclosures

Dr. Dhodapkar reported grants from the Yale School of Medicine Richard K. Gershon Fund and from the Ruth Jackson Orthopedic Society Annual Meeting Medical Student Scholarship, outside the submitted work.

Author Contributions

Conception and design: all authors. Acquisition of data: Dhodapkar. Analysis and interpretation of data: Dhodapkar. Drafting the article: Dhodapkar, Rosenow, Mechas. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Freedman. Administrative/technical/material support: Dhodapkar. Study supervision: Mechas.

Correspondence

Brett Freedman: Mayo Clinic, Rochester, MN. freedman.brett@mayo.edu.