Rheumatoid arthritis presenting as rheumatoid meningitis

Abstract

Rheumatoid meningitis (RM) is a rare extra-articular manifestation of rheumatoid arthritis (RA). A 59-year-old man presented with a 10-day history of right-sided frontal headache and a 7-day history of subacute left-sided weakness. He had no history of RA. He was febrile (38.2°C). Left ankle dorsiflexion and plantarflexion were graded at 4+/5. He developed focal onset motor seizures. He was intermittently febrile with minimal improvement despite intravenous antivirals and antimicrobials. Serology revealed elevated rheumatoid factor 88.2 IU/mL and anti-cyclic citrullinated peptide (anti-CCP) IgG >340 AU/mL. Initial cerebrospinal fluid (CSF) was predominantly lymphocytic 96%, with elevated protein 672 mg/L and normal glucose 3.4 mmol/L. Interval CSF revealed newly low glucose 2.6 mmol/L. Extensive CSF microbiology tests were negative. CSF cytology confirmed reactive lymphocytes. MRI brain revealed right frontoparietal leptomeningeal enhancement. Brain and leptomeningeal biopsy demonstrated florid leptomeningeal mixed inflammatory infiltrate without granulomas. The combination of elevated anti-CCP IgG, erosive arthropathy, CSF lymphocytosis, asymmetrical leptomeningeal enhancement and biopsy findings confirmed RM.

Keywords: headache (including migraines); meningitis; rheumatoid arthritis.

Figure 1

T2 fluid attenuated inversion recovery (FLAIR) axial MRI brain: increased signal with obliteration of sulci due to leptomeningeal thickening over the right frontoparietal lobe, with progression on four interval imaging studies over 3 weeks.

Figure 2

Recurrent fevers, focal onset motor seizures and elevated inflammatory markers.

Figure 3

Brain and leptomeningeal biopsy: florid leptomeningeal mixed inflammatory infiltrate without granulomas. There was involvement of small venules and occasional small arterioles in the leptomeninges without fibrinoid change.