Rheumatoid meningitis without a history of rheumatoid arthritis: a case report and literature review.

Rheumatoid meningitis (RM) is a rare extra-articular manifestation of rheumatoid arthritis, usually with non-specific symptoms. In most cases, head magnetic resonance imaging (MRI) shows lamellar enhancements in leptomeninges and pachymeninges, but definitive diagnosis relies on meningeal biopsies. Here, we reported a 43-year-old RM patient without a previous history of rheumatoid arthritis. He came to seek medical assistance because of fever and headache. The head MRI showed bilateral enhancements in leptomeninges and pachymeninges, and blood tests showed that serum IgM rheumatoid factor (RF) (1010.0 IU/ml) and anti-cyclic citrullinated peptide (CCP) antibody (654.24 RU/ml) became positive with a further increase with the progression of the disease. After treatment with steroids, clinical symptoms were relieved. We also reviewed previous history, symptoms, and serum, cerebrospinal fluid and imaging findings in 15 RM cases without a history of rheumatoid arthritis published since 2010. Consistent with previous reported cases, the current case suggests importance of meningeal biopsies and increases in serum RF and anti-CCP antibody in diagnosis of RM. In addition, previous joint symptoms and chronic headaches, and leptomeningeal and pachymeningeal lesions on head MRI are also of great significance for the diagnosis.