Background Rheumatoid arthritis (RA) is a multisystem autoimmune disease mainly affecting the joints. Rarely it can present with extra articular manifestations without any joint symptoms. Rheumatoid meningitis (RM) is an uncommon extra articular manifestation of the disease and can be the first presentation of RA very rarely.

Objectives A 76 year old Caucasian lady was presented with aphasia of 10 minutes duration with frontal headache. Furthermore she complained of gradual onset difficulty in walking for the last 10 months and jerky legs. She was on treatment for hypothyroidism, hypertension, anxiety and denied any joint pains. Examination showed normal cranial nerves and spastic quadriparesis with limb power of 4/5, global hyperreflexia and extensor plantar reflexes. She was also observed to have focal clonic seizures of the left lower limb. Lungs were clear. 10 days later she developed painful left wrist and metacarpophalangeal joints with swelling and tenderness.

Methods MRI of the brain with contrast showed right fronto-parietal leptomeningeal enhancement. Cerebrospinal fluid (CSF) tested repeatedly showed lymphocytic pleocytosis, normal glucose, mildly elevated proteins (0.6g/l). CSF was negative for flow cytometry, TB PCR, TB culture, antineuronal antibodies, cryptococcal antigen, viral PCR, fungal cultures, fungal studies and beta D glucan. Rheumatoid factor (141 iu/ml) and anti CCP antibodies (447u/ml) were strongly positive. CSF anti CCP antibody titre was 8 u/l. Rest of the autoimmune serology was negative. ACE level was normal. Inflammatory markers were raised. X ray of the hands showed degenerative changes only. CT chest abdomen and pelvis and FDG PET scan showed left sided axillary lymphadenopathy of which the biopsy showed reactive changes. CT also showed possible early interstitial lung disease (ILD).

Results Patient was managed with the collaboration of the neurology team, rheumatology team and input from a tertiary care center. Meningeal biopsy was not done due to the risks involved and delay in starting treatment. RM was diagnosed after exclusion of other differential diagnosis. Patient was treated with IV methyl prednisolone 1g 3 pulses and started on a tailing off regime of oral prednisolone. Hydroxychloroquine and sulfasalazine were started as disease modifying treatment. Methotrexate was avoided due to the suspicion of ILD. Patient had good recovery clinically and radiologically in 6 months.

Conclusion RM can be the first presentation of RA rarely. Hence it is important for rheumatologists to be aware of this rare manifestation. Usually patients develop joint symptoms within a year of presentation of RM [1]. Most of the patients are strongly sero positive [2]. Clinical symptoms can be diverse with focal neurological deficit, focal seizures, neuropsychiatric symptoms, stroke like episodes and headache. MRI characteristically shows meningeal enhancement. It can be confirmed with a meningeal biopsy. However RM can be diagnosed with confidence as in patient by thorough exclusion of other inflammatory, infective and paraneoplastic causes of chronic meningitis. It is postulated that anti CCP antibody levels in CSF is raised in patients with RM. Direct measurement of these values and calculation of intrathecal anti CCP antibody production based on these values are useful in diagnosing RM in patients, unable to go ahead with a meningeal biopsy [3]. Acute treatment of RM is immunosuppression with steroids that can be combined with cyclophosphamide or rituximab.

References

1. McKenna, Mary Clare et al. “Rheumatoid arthritis presenting as rheumatoid meningitis.” BMJ case reports vol. 12,1 bcr-2018-226649. 10 Jan. 2019, doi:10.1136/bcr-2018-226649
2. Lu, Lin et al. “Rheumatoid meningitis: a rare complication of rheumatoid arthritis.” BMJ case reports vol. 2015 bcr2014208745. 1 Jul. 2015, doi:10.1136/bcr-2014-208745
3. Caputi, Luigi et al. “Anti-Cyclic Citrullinated Peptide Antibody Index in the Cerebrospinal Fluid for the Diagnosis and Monitoring of Rheumatoid Meningitis.” Biomedicines vol. 10,10 2401. 26 Sep. 2022, doi:10.3390/biomedicines10102401

Acknowledgements I would like to acknowledge the contribution made by the neurology team in managing this patient.

Disclosure of Interests None Declared.

Keywords: Rheumatoid arthritis, Diagnostic Tests

DOI: 10.1136/annrheumdis-2023-eular.4943