Extensive Intraspinal Hypermetabolism Caused by Neurobrucellosis Shown on 18F-FDG PET/CT

The Role of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Management of Brucellosis: An Observational Cohort Study

Background

Diagnosis of focal infection in brucellosis is important to direct optimal treatment. Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) may be helpful in this aspect.

Methods

The clinical and imaging data of all patients with brucellosis, who underwent FDG PET/CT as part of the investigation in Rambam Health Care Campus, where FDG PET/CT became the recommended imaging modality for suspected focal infection in brucellosis since 2016, were analyzed retrospectively. The detection of focal infection as well as management modification before and after FDG PET/CT were recorded.

Results

FDG PET/CT was performed in 30 episodes of brucellosis occurring in 27 patients: 20 primary episodes and 10 suspected relapse episodes. The mean age of the patients was 50 ± 15.07 years. Focal disease was diagnosed in 18 of 30 (60%) episodes, of which 8 (26.6%) were diagnosed for the first time by FDG PET/CT, all of whom had spinal infection, with a concomitant additional focus in 5. Overall, multifocal disease was diagnosed in 10 of 18 (55.5%) of patients with focal disease. Management modification following FDG PET/CT was recorded in 17 of 30 (56.6%) episodes, mainly by treatment extension in spinal infection and withholding treatment in patients with suspected relapse but no evidence of active disease by FDG PET/CT.

Conclusions

FDG PET/CT was found to be helpful in the diagnosis of focal infection in brucellosis. Multifocal disease seems more prevalent than previously described. The clinical impact of adding FDG PET/CT to the diagnostic workup of brucellosis should be evaluated in future studies.

Case report: Revealing a special and rare autoimmune GFAP astrocytopathy in the spinal cord succeeding Neurobrucellosis infection

Brucellosis, a zoonosis, can cause an inflammatory response in most organs and continues to be a public health problem in some endemic areas, whereas neurobrucellosis is a morbid form of brucellosis that affects the central nervous system (CNS) with poor prognosis. Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is an autoimmune disease, and there have been no reports of a Brucella infection, leading to GFAP astrocytopathy. We report the case of a patient with a positive and high level of GFAP antibodies in the cerebrospinal fluid (CSF), following a Brucella infection. Although this patient did not show any responsible lesions in the diffusion sequence of the magnetic resonant imaging (MRI) scan, we found an evidence of thoracolumbar (T12) involvement on fluorodeoxyglucose (FDG) positron emission tomography (PET). The symptoms of spinal cord involvement were only partly relieved after initial treatment [doxycycline (0.1 g Bid) and rifampicin (0.6 g Qd) for 6 weeks]; however, they markedly improved after the subsequent immunosuppressive therapy [intravenous methylprednisolone (1,000 mg for 3 days)], followed by a 50% reduction from the preceding dose after 3 days, and subsequently, oral prednisone tablets (60 mg/day) was started, which was then gradually tapered [reduced to 10 mg/day every 1–2 weeks)]. The positive response to immunosuppressive therapy and treatment outcome strongly indicated the presence of an autoimmune neurological disease probably triggered by some infectious factors. Therefore, our findings reveal that a Brucella infection is one of the causes of autoimmune GFAP astrocytopathy, and when this infection is difficult to be identified by regular MRI, FDG PET can be used as a supplementary method for diagnosis and treatment.

Hypertrophic spinal pachymeningitis caused by ANCA-associated vasculitis revealed by 18F-FDG PET/CT: A case report

RATIONALE

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) can involve the central nervous system in estimatedly 15% of patients. Hypertrophic pachymeningitis causes inflammatory hypertrophy of the cranial or spinal dura mater and patients present with various neurological deficits. ANCA-associated hypertrophic spinal pachymeningitis has rarely been reported in literature. We report a case of AAV presenting with hypertrophic spinal pachymeningitis detected by 18F-FDG PET/CT.

PATIENT CONCERNS

A 66-year-old woman diagnosed with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis developed back pain, bilateral lower limb weakness, dysuria, and dysporia 1 month ago.

DIAGNOSIS

Contrast-enhanced MRI showed thickening and enhancement of the dura mater in the thoracic cord. Intraspinal hypermetabolism in the corresponding region was observed on 18F-FDG PET/CT. The patient was finally diagnosed with ANCA-associated hypertrophic spinal pachymeningitis.

INTERVENTIONS

The patient was treated with a higher dose of prednisone and cyclophosphamide.

OUTCOMES

After 2-week treatment, the patient's neurological symptoms improved rapidly and laboratory findings were ameliorated. A repeated contrast-enhanced MRI showed partial improvement of the disease in the thoracic cord.

LESSONS

18F-FDG PET/CT and contrast-enhanced MRI can aid in the clinical diagnosis and surveillance in AAV-associated hypertrophic spinal pachymeningitis and potentially facilitate early recognition and intervention to prevent irreversible neurological impairment.