Central nervous system involvement in relapsing polychondritis with inflammatory changes in the cerebrospinal fluid and cranial MRI abnormalities: a case series report

Objective To explore the clinical features of relapsing polychondritis (RP) with central nervous system (CNS) involvement as the major manifestation. Methods A total of 11 RP patients who were hospitalized in the Department of Neurology, the Affiliated Brain Hospital of Nanjing Medical University from January 2020 to December 2024 were retrospectively enrolled. Their clinical manifestations, laboratory indicators, cerebrospinal fluid (CSF) changes, and cranial magnetic resonance imaging (MRI) findings were comprehensively analyzed. Results CNS involvement was the major initial manifestation in the vast majority of RP patients (90.9%, 10/11), as cognitive impairment ( n = 10), headache ( n = 7), psychiatric/behavioral symptoms ( n = 6), epileptic seizures ( n = 4), limb numbness ( n = 4), limb weakness ( n = 4), and limb tremor ( n = 3). CSF analysis revealed an inflammatory response in the CNS, as evidenced by increased levels of neutrophils, albumin, and immunoglobulins at varying degrees. White matter degeneration ( n = 7) and brain atrophy ( n = 7) were the pronounced changes on cranial MRI. Brain lesions were mainly distributed in the cortex, subcortex, and infratentorium. Parenchymal or meningeal enhancement was observed on MRI scans in three RP patients with CNS involvement. Arterial spin labeling (ASL) detected three cases of hypoperfusion and two cases of hyperperfusion in the brain. All patients were treated with corticosteroids, and six were managed with additional immunotherapies. Finally, ten RP patients were improved and discharged. Conclusion neurological deficits vary widely in RP patients with CNS involvement, with cognitive decline as the most common feature. Inflammatory changes in the CSF indicate a neuroinflammatory mechanism involved in the pathogenesis of RP. Distinct imaging features on cranial MRI are closely associated with the involvement into CNS in RP, offering references for distinguishing the acute inflammation stage from the chronic degeneration stage during the development of RP.