Treatment of very high risk membranous nephropathy complicated by pulmonary embolism with glucocorticoids and rituximab: Case report.

RATIONALE

We report the efficacy of combination prednisolone and intravenous (IV) rituximab as an immunosuppressive regimen for a young male presenting with extensive venous thromboembolism including a submassive pulmonary embolism secondary to life-threatening nephrotic syndrome from very high risk anti-phospholipase-A2 receptor (PLA2R) positive membranous nephropathy. Initial treatment was with mechanical thrombectomy and anticoagulation. Thereafter, oral prednisolone was initiated to induce remission, during a period of uninterrupted anticoagulation. He subsequently underwent a kidney biopsy for histological confirmation and IV rituximab was administered as definitive treatment.

PATIENT CONCERNS

A 33-year-old Chinese male with no chronic conditions presented with shortness of breath and left-sided pleuritic chest pain.

DIAGNOSES

He was diagnosed with a submassive pulmonary embolism which was confirmed on computer tomography imaging with additional extensive clot burden in the inferior vena cava and renal veins. Further workup revealed nephrotic syndrome, with proteinuria of 6.5g/day, and serum Albumin 26 g/L, associated with anti-PLA2R of 223 RU/ml. His presenting serum creatinine was 108 µmol/L (CKD-EPI eGFR 77ml/min/1.73m2). Additional workup for malignancy and infections were negative.

INTERVENTIONS

As part of acute management, immediate anticoagulation was initiated. The patient then underwent endovascular thrombectomy and inferior vena cava filter placement. Given the emergent indication for and need for 4 weeks of uninterrupted anticoagulation, his kidney biopsy had to be delayed. The patient was then preemptively treated with IV Methylprednisolone 500mg for 3 days followed by 0.5mg/kg of oral prednisolone after taking into consideration the specificity of PLA2R positivity for membranous nephrology.

OUTCOMES

After 4 weeks of treatment, serum albumin improved to 32 g/L and anti-PLA2R levels improved significantly to 27 RU/ml. His subsequent kidney biopsy confirmed membranous nephropathy and 2 doses of IV rituximab 1g were administered 14 days apart. Six months after initial presentation, the patient is in partial remission. Albumin has improved to 41 g/L, Anti PLA2R < 2 RU/ml, and proteinuria is 1.18g/day.

LESSONS

This case demonstrates that preemptive treatment in patients with anti-PLA2R positive membranous nephropathy can initiated without a histological diagnosis when there are strong contraindications against a kidney biopsy. Treatment with a combination of steroids and IV rituximab could be a viable treatment option for patients with very high-risk membranous nephropathy over conventional therapy with cyclophosphamide.