MRI and clinical features of acute fungal discitis/osteomyelitis

Fungal Musculoskeletal Infections: Comprehensive Approach to Proper Diagnosis

Fungal musculoskeletal infections often have subacute or indolent manifestations, making it difficult to distinguish them from other diseases and infections, given that they are relatively uncommon. Fungal infections occur by hematogenous spread, direct inoculation, or contiguous extension and may be related to different risk factors, including immunosuppression and occupational activity. The infection can manifest in isolation in the musculoskeletal system or as part of a systemic process. The fungi may be endemic to certain regions or may be found throughout the world, and this can help to narrow the diagnosis of the etiologic agent. Infections such as candidiasis, cryptococcosis, aspergillosis, and mucormycosis are often related to immunosuppression. On the other hand, histoplasmosis, paracoccidioidomycosis, coccidioidomycosis, and blastomycosis can occur in healthy patients in geographic areas where these infections are endemic. Furthermore, infections can be classified on the basis of the site of infection in the body. Some subcutaneous infections that can have osteoarticular involvement include mycetoma, sporotrichosis, and phaeohyphomycosis. Different fungi affect specific bones and joints with greater prevalence. Imaging has a critical role in the evaluation of these diseases. Imaging findings include nonspecific features such as osteomyelitis and arthritis, with bone destruction, osseous erosion, mixed lytic and sclerotic lesions, and joint space narrowing. Multifocal osteomyelitis and chronic arthritis with joint effusion and synovial thickening may also occur. Although imaging findings are often nonspecific, some fungal infections may show findings that aid in narrowing the differential diagnosis, especially when they are associated with the patient's clinical condition and history, the site of osteoarticular involvement, and the geographic location. ©RSNA, 2024.

Imaging of Spondylodiscitis: A Comprehensive Updated Review-Multimodality Imaging Findings, Differential Diagnosis, and Specific Microorganisms Detection

Spondylodiscitis is defined by infectious conditions involving the vertebral column. The incidence of the disease has constantly increased over the last decades. Imaging plays a key role in each phase of the disease. Indeed, radiological tools are fundamental in (i) the initial diagnostic recognition of spondylodiscitis, (ii) the differentiation against inflammatory, degenerative, or calcific etiologies, (iii) the disease staging, as well as (iv) to provide clues to orient towards the microorganisms involved. This latter aim can be achieved with a mini-invasive procedure (e.g., CT-guided biopsy) or can be non-invasively supposed by the analysis of the CT, positron emission tomography (PET) CT, or MRI features displayed. Hence, this comprehensive review aims to summarize all the multimodality imaging features of spondylodiscitis. This, with the goal of serving as a reference for Physicians (infectious disease specialists, spine surgeons, radiologists) involved in the care of these patients. Nonetheless, this review article may offer starting points for future research articles.

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).

Discitis-osteomyelitis: optimizing results of percutaneous sampling

Vertebral discitis-osteomyelitis is an infection of the spine that involves the intervertebral disc and the adjacent vertebral body but may also extend into the paraspinal and epidural soft tissues. If blood cultures and other culture data fail to identify a causative microorganism, percutaneous sampling is indicated to help guide targeted antimicrobial therapy. Despite limited supporting evidence, withholding antimicrobial therapy for up to 2 weeks is recommended to maximize microbiological yield, although literature supporting this recommendation is limited. During the procedure, technical factors that may improve yield include targeting of paraspinal fluid collections or soft tissue abnormalities for sampling, acquiring multiple core samples if possible, and use of larger gauge needles when available. Repeat sampling may be indicated if initial percutaneous biopsy is negative but should be performed no sooner than 72 h after the initial percutaneous biopsy to ensure adequate time for culture results to return.

Unveiling the Culprit: Candida-Induced Spondylodiscitis Following SARS-CoV-2 Infection

We present a case of a 57-year-old male patient with a history of prolonged intensive care unit (ICU) stay for coronavirus disease 2019 (COVID-19) who developed fungal spondylodiscitis, a rare complication. The patient initially presented complaining of respiratory symptoms and was subsequently treated with tocilizumab, remdesivir, enoxaparin, and dexamethasone. Following ICU discharge, he experienced recurrent infections, including extended-spectrum beta-lactamase Klebsiella urinary tract infection. Two months later, he developed back pain; magnetic resonance imaging (MRI) revealed inflammatory spondylodiscitis. Despite empirical antibiotic therapy, his condition did not improve, and a bone biopsy confirmed Candida albicans infection. Antifungal treatment with fluconazole and anidulafungin resulted in a significant clinical improvement. The patient achieved complete recovery after six months of therapy. This case highlights the rare occurrence of fungal spondylodiscitis in COVID-19 patients with a history of ICU stay and emphasizes the importance of early recognition and appropriate management to mitigate potential complications.

A Combined Scoring Method Based on 18F-FDG PET/CT for Distinguishing Spinal Infection From Malignancy

STUDY DESIGN

Retrospective study.

OBJECTIVE

This study aimed to explore the additional value of fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for the detection of early-stage and atypical spinal infections and to find the best combination of indicators from laboratory and imaging systems for higher diagnostic efficiency.

SUMMARY OF BACKGROUND DATA

Diagnosis of early-stage and atypical spinal infections may be challenging for clinicians. It is particularly important to distinguish spinal infection from malignancy to develop a timely treatment strategy and avoid unnecessary biopsy or surgery.

MATERIALS AND METHODS

All patients with a discharge diagnosis of spinal infection or malignancy who underwent 18F-FDG PET/CT scans before spinal biopsy between January 1, 2014, and July 30, 2021, were included. Laboratory and imaging data were assessed. A receiver operating characteristic (ROC) curve was created, and the best cut-off point and cumulated area under the curve (AUC) were obtained to distinguish between spinal infection and malignancy. Kappa values were used to assess the agreement between the 18F-FDG PET/CT and MRI findings. Binary logistic regression was used to screen for statistically significant indicators and imaging findings.

RESULTS

A total of 71 patients with confirmed spinal infections (n=30) or malignancies (n=41) were included in this study. Elevated ESR and significantly elevated tumor biomarkers or positive FLCs assay were significantly different between the two groups. In addition to the total lesion glycolysis of the involved vertebral bodies derived from 18F-FDG PET/CT, four imaging findings (consecutive multilevel vertebral lesions, intervertebral disc, vertebral arch, and extraspinal involvement) also showed significant differences between the two groups (P≤0.010). A combined scoring method based on the above seven indicators was designed with an overall classification accuracy of 95.2%, and it identified all patients with spinal infections (100%, 28/28). In addition, moderate-to-excellent agreement could be reached for the involvement of intervertebral discs, paravertebral soft tissues, and vertebral arches derived from MRI and18F-FDG PET/CT.

CONCLUSIONS

The combined scoring method based on 18F-FDG PET/CT provided excellent overall accuracy in distinguishing spinal infections from malignancies. This approach may prove useful for patients with MRI contraindications or with equivocal results following laboratory tests or traditional imaging when there is high suspicion for spinal infections or malignancy.

Case Report: SARS-CoV-2 Infection-Are We Redeemed? A Report of Candida Spondylodiscitis as a Late Complication

Background: We describe a case of candida spondylodiscitis secondary to coronavirus disease (COVID-19). Case report: A 47-year-old man diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) required prolonged admission to the intensive care unit (ICU). Four months later, he was diagnosed with thoracic candida spondylodiscitis. Medical management was insufficient, so he eventually underwent surgery. Discussions: Fungal infections seem to be more likely in patients with COVID-19, but it is unknown whether they are directly attributed to COVID-19 or other surrounding factors. Regardless of the answer, the diagnosis is complicated, and the mortality rate is high. Lessons: COVID-19 is posing a challenge to the society, and new and unexpected diseases that had once disappeared have risen again. It is our duty to suspect them and to treat them in the most effective way possible.

Differentiation between infectious spondylodiscitis versus inflammatory or degenerative spinal changes: How can magnetic resonance imaging help the clinician?

Spondylodiscitis is a complex disease whose diagnosis and management are still challenging. The differentiation between infectious and non-infectious aetiology is mandatory to avoid delays in the treatment of life-threatening infectious conditions. Imaging methods, in particular magnetic resonance imaging (MRI), play a key role in differential diagnosis. MRI provides detailed anatomical information, especially regarding the epidural space and spinal cord, and may allow differential diagnosis by assessing the characteristics of certain infectious and inflammatory/degenerative lesions. In this article, we provide an overview of the radiological characteristics and differentiating features of non-infectious inflammatory spinal disorders and infectious spondylodiscitis, focussing on MRI results and presenting relevant clinical and pathological features that help early diagnosis.

Pathophysiology and MRI Findings of Infectious Spondylitis and the Differential Diagnosis

MRI에서 추간판의 이상 신호와 위, 아래 척추체 종판의 파괴, 종판 주변의 골수부종 등은 감염성 척추염의 전형적인 소견으로 여겨지나 퇴행성 척추질환, acute Schmorl's node, 척추관절병증, synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO)/chronic recurrent multifocal osteomyelitis, 척추신경관절병증, calcium pyrophosphate dehydrate 결절침착질환 등 다양한 비감염성 척추질환에서도 나타날 수 있다. MRI에서 이러한 비감염성 척추질환과 감별되는 감염성 척추염의 영상 소견은 추간판의 고신호와 농양, 척추 연부조직의 농양, 그리고 T1 강조영상에서 저신호로 보이는 종판의 경계가 불명확해지는 점 등이다. 그러나 이러한 감별점이 항상 적용되는 것은 아니며 감염성, 비감염성 질환의 영상 소견에 유사점이 많기 때문에 정확한 진단을 위해서는 감염성 척추염뿐만 아니라 감염과 감별해야 하는 다양한 질환의 병태생리와 연관된 영상학적 특징을 아는 것이 중요하다.

Discitis Following Radiofrequency Nucleoplasty: A Case Report

Introduction

Radiofrequency nucleoplasty is a minimally invasive procedure to treat chronic low back pain, especially mild degenerative disc diseases. Discitis after radiofrequency nucleoplasty is a rare case.

Case Presentation

A 62-year-old male patient with a chief complaint of 10 years low back pain, gradually worsening for the last two years, a history of hypertension, chronic kidney disease, and routine dialysis twice a week, referred to the center. He underwent a lumbar medial branch block using radiofrequency and radiofrequency nucleoplasty procedure of lumbar 4-5 (L4-L5). Three weeks after the intervention, he could not move his legs, associated with urinary and fecal incontinence. MRI (magnetic resonance imaging) of the lumbar spine was performed, and the results indicated hyperintensity in L4-L5, suspicious of discitis. Laminectomy at L4 and L5 was performed. Eight months after surgery, the patient could feel and lift legs, and urinary and fecal incontinence was also controlled.

Conclusions

Early diagnosis of discitis is critical and challenging. Delay in diagnosis may lead to treatment delay and the development of neurological deficits. Comprehensive treatment with bed rest, antimicrobial therapy, and sensible application of timely surgery are essentials to an optimal outcome.