Rheumatoid meningitis in a patient with overlap syndrome: The usefulness of anti-citrullinated peptide antibodies determination in CSF.

Rheumatoid meningitis (RM) is a rare complication of rheumatoid arthritis that can manifest as stroke-like episodes. We present the case of a 63-year-old woman with a past history of overlap syndrome and clinical manifestations suggestive of amyopathic dermatomyositis, rheumatoid arthritis, and systemic lupus erythematosus. She presented to the emergency department with sudden onset right-sided clumsiness and numbness, as well as a 2-week history of left hemicranial headache. Laboratory workup revealed positive serum antinuclear antibodies, anti-Ro antibodies, anti-citrullinated peptide antibodies (ACPA), and elevated rheumatoid factor. Lymphocytic pleocytosis, positive ACPA and anti-Ro antibodies with passive diffusion pattern, and negative microbiological studies were demonstrated in the CSF. Brain magnetic resonance imaging showed predominant left fronto-parieto-occipital leptomeningeal and pachimeningeal enhancement. She was diagnosed with RM and received methylprednisolone IV mg/kg once daily. Stroke-like episodes in the setting of a patient with lymphocytic pleocytosis in the cerebrospinal fluid (CSF) and meningeal enhancement should raise suspicion of RM. In this context, serum rheumatoid factor and ACPA levels should always be measured and ACPA should also be measured in CSF. To our knowledge, this is the first reported case of RM in the context of an overlap syndrome. ACPA levels in CSF could be a relevant diagnostic clue in the setting of central nervous system disturbance and overlapping autoimmune conditions that include rheumatoid arthritis. In our case, the presence of a suggestive clinical scenario of RM reinforces the probable pathogenic role of ACPA when it is present in the central nervous system, even without intrathecal synthesis evidence.