Neuropsychiatric Systemic Lupus Erythematosus Diagnosed Following Treatment Initiated for Acute Encephalitis

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by diverse clinical manifestations. This case report describes a 14-year-old female patient diagnosed with neuropsychiatric SLE (NP-SLE) following status epilepticus. The patient was a 14-year-old previously healthy female and was transported to the emergency department owing to fever and status epilepticus. Based on imaging findings, clinical findings, and the patient's age, anti-N-methyl-D-aspartate (NMDA) receptor encephalitis (NMDARE) was suspected, and intensive care was initiated. However, persistent renal dysfunction and cytopenia prompted detailed investigation, leading to a diagnosis of NP-SLE. SLE is a systemic disease requiring long-term treatment. In such cases, where characteristic rashes are absent, differential diagnosis based on physical findings is difficult. Although NP-SLE and NMDARE share many standard features, including clinical symptoms and age of onset, measuring antinuclear antibody (ANA) and complement levels may be valuable in the differential diagnosis.