Recurrent polychondritis complicated with demyelinating encephalopathy and limbic encephalitis: a case report and literature review

Recurrent polychondritis (RP) is a rare systemic autoimmune disorder that rarely involves the central nervous system (CNS). This report describes a 68-year-old male RP patient who was admitted with bilateral auricular swelling and pain that had lasted for one month, accompanied by limb weakness and pain that had lasted for ten days. Neurological assessment revealed sluggish responses, dysarthria, decreased limb muscle strength and urinary/bowel dysfunction, with a Montreal Cognitive Assessment (MoCA) score of 21/30. Laboratory tests showed elevated inflammatory markers, and autoantibodies in the serum and cerebrospinal fluid (CSF) were negative. CSF analysis revealed increased intracranial pressure and elevated protein levels, as well as decreased immunoglobulin and complement levels. A brain MRI revealed bilateral periventricular, centrum semiovale, and medial temporal lobe fluid-attenuated inversion recovery (FLAIR) hyperintensities. The diagnosis of RP was confirmed based on the Damiani–Levine criteria, alongside the diagnoses of autoimmune limbic encephalitis (LE) and secondary demyelinating encephalopathy (DE). Following treatment with methylprednisolone pulse therapy followed by cyclophosphamide, the patient’s symptoms improved significantly. At the three-month follow-up, limb muscle strength had recovered, but urinary dysfunction persisted. This case demonstrates that RP can affect the CNS and the central-autonomic axis. Early recognition and initiation of immunotherapy can improve prognosis.