POS0606 PREVALENCE, CLINICAL, RADIOLOGICAL, AND PATHOLOGICAL EVALUATION OF 11 MENINGEAL INVOLVEMENT IN RHEUMATOID ARTHRITIS
Authors: E. Unaldi, S. Önder, G. Ayan, M. Ekici, A. Tuncer, M. A. Topcuoglu, R. Göçmen, U. Kalyoncu
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Rheumatoid arthritis (RA) is a systemic inflammatory disease that can affect many different organ systems; of which, CNS involvement is less common and more difficult to recognize clinically. Rheumatoid meningitis (RM) is a rare CNS manifestation that can occur in RA. <h3>Objectives:</h3> This single-center study aimed to evaluate the demographic and clinical characteristics, magnetic resonance imaging (MRI) findings, treatment options, and prognosis of patients with rheumatoid arthritis and meningitis. <h3>Methods:</h3> Between 2010 and 2022, patients with ICD-10 codes for RA who underwent brain MRI at our hospital were screened (n= 2945). During the evaluation of MRI scans of 2945 patients, 94 patients were found to have suspected meningeal involvement. Following the confirmation of their RA diagnoses, 21 patients with suspected rheumatoid meningitis were identified. The radiologist reviewed the MRI scans again, and the study included 11 patients with definite meningitis. The accuracy of diagnosing RA using ICD-10 codes was determined to be 35% in our hospital (1). The estimated number of potential patients with rheumatoid arthritis during this period was approximately seven thousand. Demographic characteristics, disease duration, acute phase responses, disease activity, RF/anti-CCP levels, and extra-articular manifestations. The medical treatments and any existing comorbidities were recorded. The neurological findings were reported and the cerebrospinal fluid (CSF) analysis for cell count and oligoclonal bands, and the EEG results were recorded. The radiology department reviewed brain MRIs both at baseline and follow-up. They analyzed anatomical location, laterality, meningeal and parenchymal involvement, sulcal hyperintensity, diffusion limitation, and presence of hydrocephalus. Results of meningeal biopsy documented, if available. <h3>Results:</h3> Out of 7000 patients diagnosed with RA, only 11 patients (0.15%) had meningeal involvement. Eight patients were women, with a median age of 61 (50-74). All patients had positive serological results for RF/ACPA. Acute phase response was high in 91% of the patients during meningitis. In two patients, meningitis was diagnosed before RA, while in the other two, it was diagnosed concurrently with RA. The period between RA and meningitis was 12.4 years. At meningitis, two patients had active RA. Seven out of all patients had extra-articular involvement. Neurological symptoms included focal symptoms (72.7%), neuropsychiatric symptoms (54.5%), headache (45.4%), seizures (27.2%), and movement disorders (18.1%). CSF was examined for ten patients, with 2 having low glucose levels (20%), 7 having high protein levels (70%), and 6 having a predominance of MN cells (60%). Table 2 shows the patients' affected brain region and meningeal involvement sites. Treatment information was available for ten patients, all of whom received high-dose steroids, 7 of whom were given pulse steroids, 5 rituximab, and five were given cyclophosphamide. 8 of the nine patients had complete or partial response. <h3>Conclusion:</h3> The prevalence of meningeal involvement in RA patients is unknown. In a 12-year follow-up study at a tertiary center, meningeal involvement was observed in only 0.15% of RA patients. This is the most extensive study ever conducted at a single center to evaluate meningeal involvement in patients with RA. Different neurological presentation patterns and meningeal inflammation may occur before the diagnosis of RA. The main treatment options for this condition are glucocorticoids and rituximab/cyclophosphamide. However, patients may also experience changes such as hydrocephalus. <h3>REFERENCES:</h3> [1] Ekici M, Baytar Y, Kardas RC, Sari A, Akdogan A, Durhan G, Ariyurek M, Kalyoncu U. Predictors of mortality in rheumatoid arthritis-associated lung disease: A retrospective study on ten years. Joint Bone Spine. 2021 May;88(3):105133. doi: 10.1016/j.jbspin.2021.105133. Epub 2021 Jan 20. PMID: 33484860. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>