Rheumatoid Pachymeningitis as the Sole Manifestation of Rheumatoid Arthritis

Sir, Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammatory arthritis as well as involves many different organ systems; among them, central nervous system (CNS) involvement is less common and more difficult to recognize clinically. Rheumatoid meningitis (RM) is a rare CNS manifestation that can occur in RA, with less than 50 cases reported to date. There have been few case reports of rheumatoid pachymeningitis in patients with longstanding seropositive RA with erosive arthritis, but rheumatoid pachymeningitis as presenting manifestation of RA is very rare. We, hereby, present a case of rheumatoid pachymeningitis in a seropositive patient without arthritis. A 47-year-old male presented with a 9-year history of episodic left hemi cranial headaches associated with transient right-sided weakness with symptoms lasting from 5 min up to 2 h and occurring multiple times in a day. The total duration of attacks lasted for 15 to 25 days, attacks remitting by themselves, with a frequency of 1 attack/year to no attacks in between for up to 4 years. The patient had previously been treated as having transient ischemic attacks and focal epilepsy. His recent attack was of 10 days duration, presenting with left hemi cranial headache along with fluctuating right-sided weakness. The patient had no other systemic symptoms or signs. His magnetic resonance imaging (MRI) scan of the brain with contrast showed sheet-like dural enhancement along the interhemispheric falx overlying left frontoparietal convexity with increased signal in the adjacent brain parenchyma [Figure 1a and c], with normal brain and neck angiography and normal electroencephalogram (EEG). Complete blood count and renal and liver biochemistry were unremarkable. Inflammatory markers like erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were raised. Cerebrospinal fluid (CSF) analysis revealed cell count of 3/μL, proteins were 47.2 mg/dl and CSF IgG index was 0.04. Gram staining, ZN staining and CSF culture were all negative. Serology for cryptococcus, brucella and syphilis was also negative. There was no evidence of sarcoidosis, lymphoma or other inflammatory diseases. Angiotensin-converting enzyme, immunoglobulins, and protein electrophoresis were all within the normal range. Antinuclear antigen (ANA) was +1, showing homogenous pattern but extractable nuclear antigen profile, p-ANCA and c-ANCA were negative. Rheumatoid factor (RF) was normal but antibody to the cyclic citrullinated peptide (anti-CCP) was >200 U/ml. Hand X-rays were normal. No findings suggestive of any malignancy were seen on computed tomography scan of the chest, abdomen, and pelvis. Biopsy could not be performed because of institutional limitations. We considered rheumatoid pachymeningitis as a diagnosis as all tests done for alternate etiologies of pachymeningitis were negative and the patient had high levels of anti-CCP. The patient was treated with prednisolone and methotrexate therapy. The patient became asymptomatic during the hospital stay, his prednisolone was tapered off in a month while he continued methotrexate 15 mg weekly and over 18 months of follow-up period he has remained asymptomatic. His ESR on follow-up was 6 mm/hour and repeat MRI brain was normal [Figure 1b and d].Figure 1: (a) T1 contrast magnetic resonance imaging scan of the brain coronal section showing dural enhancement overlying left frontoparietal convexity and the interhemispheric falx and (b) Follow-up magnetic resonance imaging scan showing resolution of dural enhancement. (c) Magnetic resonance imaging scan brain coronal section of FLAIR (fluid attenuated inversion recovery) image showing intraparenchymal hyperintensity in the parietal lobe and (d) Follow-up magnetic resonance imaging scan showing resolution of the previous lesionRheumatoid pachymeningitis is a rare extra-articular nervous system complication of RA and can occur either in initial years or after many years of clinical disease.[1] On the basis of a review of all the 39 published cases of RM, mean age of presentation is 65 years, more commonly seen in women (2:1), and 45% patients had less than 5 years of diagnosed RA, while 13% of patients did not have a diagnosis of RA before presentation with RM.[2] Rheumatoid pachymeningitis presents with varied symptoms, usually episodic, that include headaches, confusion, transient ischemic attacks (TIA), or stroke-like symptoms, seizure-like activity, and psychiatric symptoms.[3] In our case, the onset of disease was at 38 years of age with rheumatoid pachymeningitis being the sole manifestation of RA even after 9 years of neurological symptoms. Even though RF was negative in our patient, anti-CCP was >200 U/ml, which is highly specific (93%–98%) for RA along with raised ESR and CRP.[3] Previous reports mentioned treating patients with a corticosteroid, methotrexate, cyclophosphamide, and rituximab.[2] Our patient showed clinical and radiological resolution after treatment with prednisolone and methotrexate. Prednisolone was tapered over time and the patient remained stable on methotrexate monotherapy. Keeping in mind that the patient did not develop any typical features of RA even after 9 years, we should entertain the possibility of idiopathic hypertrophic meningitis as a differential diagnosis, as it has a similar clinical and radiological presentation.[4] To summarize, rheumatoid pachymeningitis should be considered as a diagnostic possibility in the proper clinical setting, when evidence of abnormal meningeal enhancement is found on enhanced MRI, even without the presence of systemic manifestations of RA. 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