P YEE MIA LEUNG1, D GASPARINI1, S FORD1
1St Vincent’s Hospital Melbourne, Melbourne, Australia
We describe the case of a 29-year-old female with a background of poorly-controlled type one diabetes mellitus diagnosed at age 8, complicated by proliferative retinopathy, who presented with acute kidney injury and nephrotic syndrome. She reported a four month history of frothy urine, peripheral oedema, weight gain and hypertension. Serum creatinine was 160μmol/L, with a baseline creatinine 90μmol/L two months prior, albumin was 19g/L and total cholesterol was 6.6mmol/L. Urinalysis revealed 50×106/L erythrocytes and a 24-hour urine protein excretion was 19.3g. A glomerulonephritis screen was negative and renal imaging was normal. A renal biopsy showed typical diabetic changes of nodular glomerulosclerosis. Additionally, there were atypical features of fibrocellular crescents and fibrinoid necrosis in 3 out of 7 glomeruli. Immunofluorescence revealed strong linear glomerular basement membrane staining, indicative of anti-GBM disease. She was treated with high-dose corticosteroids, plasma exchange and oral cyclophosphamide (cumulative dose 4.9g). Three months later, she presented with haemoptysis. Serum anti-GBM antibody and ANCA remained negative. She was treated with plasma exchange and IV rituximab 375mg/m2 for four weekly doses. Due to worsening renal function and diuretic-resistant fluid overload, she commenced haemodialysis and transitioned to peritoneal dialysis. The evidence for rituximab to deplete the pathogenic anti-GBM antibody is limited to case reports. Rituximab was used due to disease refractory to standard treatment and complications of cyclophosphamide. The efficacy of rituximab in seronegative anti-GBM disease is unclear and this case report adds to the body of evidence for its use.
Dr Leung is a third year nephrology advanced trainee at Eastern Health, with interests in kidney transplantation and peritoneal dialysis.