On December 8, 2020, A 34-year-old Chinese woman was found to have renal failure (creatinine of 778.4 umol/L) due to frequent vomiting. She had not any medical history. Initial investigation showed renal failure, moderate anemia, abnormal calcium and phosphorus metabolism, normal complement and autoimmune antibodies test (supplementary table 1). A kidney biopsy was performed to confirm the etiology of the renal failure, which presented crescent glomerulonephritis, and multiple immune complexes deposition in the mesangial, subcutaneous and subepithelial areas with membranoproliferative and “full-house nephropathy” pattern (figure 1, 2).

She was initiated on peritoneal dialysis (PD) due to renal failure. After kidney biopsy, she received prednisone and intravenous cyclophosphamide monthly. On January18th, 2021, she had a sudden, unprovoked seizure with loss of consciousness that lasted about 6 minutes. She had no previous history of seizures. Susceptibility-Weighted Imaging (SWI) showed hemosiderosis deposits in cerebellar hemisphere and occipital lobe (figure 3). Immunoglobulin (IVIG) , methylprednisolone, and hydroxychloroquine (HCQ) was chonsen to treatment. But given that the subsequent serious pulmonary bacterial infection, fungal enteritis and severe myelosuppression, she was no longer treated with cyclophosphamide. After infection control, HCQ and low-dose mycophenolate mofetil (MMF) was chosen as maintenance treatment. The prednisolone taper was continued to a dose of 10mg/day. The treatment is effective and the brain lesion was obviously shrinked after 6 months (figure 3). She had no further seizures and no other specific clinical symptoms within more than 3 years of clinical follow-up .