Rheumatoid Leptomeningitis: Radiological Alteration of Cerebral Hypoperfusion and Subarachnoid Lesions

A 56-year-old man with rheumatoid arthritis developed emotional lability and myoclonic seizure in the left arm, followed by fever and generalized convulsion. Brain magnetic resonance imaging (MRI) revealed leptomeningeal lesions with abnormal enhancement. MRI lesions were localized predominantly in the right cerebral subarachnoid spaces. Electroencephalogram showed epileptogenic focus at the right frontal and central points. After administration of valproate sodium improved convulsion and myoclonus, single photon emission computed tomography (SPECT) using N-isopropyl-p-I-123-iodoamphetamine was performed. Brain SPECT displayed hypoperfusion predominantly in the right cerebral hemisphere. Cerebrospinal fluid (CSF) disclosed mild pleocytosis and marked elevations of interleukin-6 levels. Repeated CSF analyses showed cytology of class I and negative results for infectious pathogens. Methylprednisolone pulse therapy (1 g for 3 days, iv) and subsequent prednisolone administration (daily 50 mg, po) ameliorated neurological symptoms dramatically. Prednisolone was tapered to 20 mg/day for 5 months. Leptomeningeal MRI lesions were attenuated gradually followed by restoration of cerebral hypoperfusion on SPECT. He was diagnosed as rheumatoid leptomeningitis (RLM). Although clinical features of RLM exhibited variable deficits of the central nervous system (CNS), MRI failed to detect the corresponding CNS lesions. We first highlighted neuroradiological changes of cerebral hypoperfusion and leptomeningeal lesions in RLM. These neuroimages of our patient supported that leptomeningeal inflammation and the adjacent cerebrocortical ischemia could cause encephalitis-like symptoms in RLM patients.