Limbic encephalitis in a patient with systemic lupus erythematosus successfully treated with high-dose glucocorticoids and intravenous cyclophosphamide therapy: the potential pathogenicity of anti-glutamate receptor antibodies.

Limbic encephalitis (LE) is a clinically defined syndrome characterised by an acute or subacute impairment of short-term memory, seizures and psychiatric symptoms (i.e. depression, anxiety and hallucination). LE could come from certain conditions where the neuropsychiatric systemic lupus erythematosus (NPSLE) of the multiple central nervous system is layered. In this report, we describe a 46-year-old Japanese female with SLE that suddenly presented with seizures, sensory aphasia and pseudobulbar affect. She was diagnosed with severe NPSLE presenting clinical LE (LE-SLE) by excluding malignancies, infectious encephalitis and symptomatic epilepsy using diffusion-weighted magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT). The patient showed a rapid response to treatment with methylprednisolone pulses followed by high-dose prednisolone and intravenous cyclophosphamide. She had elevated anti-glutamate receptor antibodies (anti-GluRs) in her serum and cerebrospinal fluid (CSF) on admission, and the titres decreased to a normal range at a one-year follow up. Our case highlights the importance of measuring anti-neuron antibodies including anti-GluRs in NPSLE patients, and suggests that the reduction of these pathogenic autoantibodies in serum or CSF could be a prognostic marker.