Collapsing focal segmental glomerulosclerosis successfully treated with combination of steroid pulse and low-density lipoprotein apheresis: lessons for the clinical nephrologist

A 68-year-old woman presented with edema. Laboratory data (Online Table 1) showed hypoproteinemia, renal function impairment, dyslipidemia, proteinuria (18.5 g/g of creatinine), and hematuria. No hypocomplementemia, vasculitis, collagen disease, infection, or any new medications were noted. The patient was urgently admitted to the hospital for nephrotic syndrome and acute kidney injury (AKI) [with an estimated glomerular filtration rate (eGFR) of 34 mL/min/1.73 m2], and underwent a renal biopsy on day 2. Histopathological examination (Fig. 1) revealed that approximately 10% of the glomeruli were sclerotic, and the remaining showed focal proliferation of the epithelial cells in the Bowman’s cyst with infiltration of foamy histiocytes. Several lesions similar to cellular crescents appeared due to the proliferation of the epithelial cells. The tuft collapsed segmentally with a mildly increased matrix, proximal to the vascular pole. Fluorescence showed no deposition of immunoglobulin or complement. Electron microscopy revealed extensive loss of foot processes. Therefore, the diagnosis was collapsing focal segmental glomerulosclerosis (FSGS). No malignancy or other diseases were observed on imaging investigation. Prednisolone 50 mg/day was administered on days 3–12 (Fig. 2). On day 12, her renal function further deteriorated with an eGFR of 12 ml/min/1.73 m2, and hemodialysis was initiated. On day 13, methylprednisolone pulses were started (1000 mg methylprednisolone for three days). Renal function recovered gradually, and hemodialysis was discontinued on day 22. On day 29, a second course of methylprednisolone pulse therapy was started. On day 39, the patient’s eGFR level increased to 52 ml/min/1.73 m2, however, proteinuria remained at 3.2 g/ gCr. Low-density lipoprotein apheresis (LDL-A) was initiated on day 39 due to dyslipidemia and was subsequently performed 12 times until day 79. Proteinuria was 2.2 g/ gCr on day 81 following completion of low-density lipoprotein apheresis. Hypoproteinemia and lipid normalised, and prednisone was tapered (Online Resource 2). On day 156, due to a new increase in proteinuria, a third course of methylprednisolone pulse therapy was started. Proteinuria sustainably improved, and complete remission was achieved on day 326. Prednisone was tapered until discontinuation on day 533. Renal function normalized (proteinuria, 0.06 g/gCr; eGFR, 60 ml/min/1.73 m2 on day 1,394), and no recurrence of nephrotic syndrome occurred so far.