A 65-year-old female with comorbidities including HIV and breast cancer in remission presented with new-onset psychosis, characterized by paranoid delusions and auditory and visual hallucinations. Upon admission, she exhibited mild asymmetric resting tremor and speech hesitancy. Her neurological exam subsequently progressed to reveal marked parkinsonism, including bradykinesia, cogwheel rigidity, hypophonia, hypomimia, freezing of gait, and mutism, alongside persistent psychotic symptoms. There were no systemic symptoms or signs, such as skin or joint manifestations.
Extensive workup, including brain MRI and CSF analysis, ruled out metabolic, infectious, neoplastic, and structural causes. Dementia with Lewy bodies, drug-induced parkinsonism, leptomeningeal carcinomatosis, and autoimmune encephalitis were considered but excluded based on clinical course and serum and CSF studies. Serology revealed positive ANA, anti-Sm, and hypocomplementemia, leading to a diagnosis of neuropsychiatric SLE per 2019 EULAR/ACR criteria. Treatment with high-dose steroids, plasmapheresis, cyclophosphamide, and hydroxychloroquine resulted in resolution of both psychiatric and parkinsonian symptoms, with sustained remission at 6-month follow-up.