[Case of relapsing polychondritis followed by cognitive impairment]

A 64-year-old man developed cognitive impairment. A neurological examination showed hypereactive tendon reflex. A cerebrospinal fluid (CSF) examination showed a mild increase in both the number of mononuclear cells (14 cells/mm3) and the protein level (45 mg/dl). An electroencephalogram showed diffuse slow wave activity. Brain MR images revealed multifocal lesions in the limbic area and white matter regions. He was suspected to have autoimmune encephalitis and his symptoms improved after treated with methylprednisolone (1 g/day for 3 days). Despite this treatment, his mental disorders later relapsed. His condition improved after undergoing repeated treatment. Thereafter, he developed bacterial meningoencephalitis which had been caused by Listeria monocytogenes during the period of the internal administration of steroids. Antibiotics successfully cured his Listeria meningoencephalitis. He thereafter developed conjunctivitis, polyarthritis, hearing difficulties, dizziness and auricular chondritis. Based on these findings, we diagnosed the patient to have relapsing polychondritis (RP). It was thus conceivable that his cognitive impairment has been caused by CNS vasculitis associated with RP. RP therefore should be carefully taken into consideration and be included in the differential diagnosis as a possible cause for CNS vasculitis.