Chapter 27: Membranous Nephropathy
A 65-year-old man, with a past history of hypertension controlled on amlodipine, presented to the ER with bilateral lower limb swelling for the past 10 days. He has a 30-year history of smoking 1 pack per day but quit 5 years ago. On review he mentions increased frothiness in his urine. His physical examination reveals a blood pressure of 140/90 mm Hg, and a heart rate of 80 beats/min. He has bilateral lower limb swelling extending to the thighs. He weighs 80 kg compared to a baseline of 75 kg 3 months ago. Cardiovascular examination shows normal heart sounds. His chest is clear to auscultation. The rest of his examination is unremarkable. On laboratory investigations, his serum creatinine is 1.7 mg/dL, 24-hour urine protein is 10 g/day. Serum albumin is 11 g/L, hemoglobin 123 g/L. His kidney biopsy shows features of membranous nephropathy, with GBM thickening on light microscopy and by IF, IgG and C3 deposition in a granular fashion was seen and confirmed by subepithelial electron dense deposits on EM. His glomerular tissue staining for PLA2R is positive.
Which of the following steps in management should NOT be introduced at this time?
A. Add ramipril 5 mg once daily.
B. Start cyclosporine 125 mg twice daily.
C. Begin anticoagulation for venous thromboembolism prophylaxis.
D. Obtain CT chest to rule out lung cancer.
The answer is B. The patient has newly diagnosed MN. Although he is anti-PLA2R positive, the long history of smoking makes it imperative that lung cancer is rule out by performing a chest CT. He is hypertensive and thus should be started on angiotensin II blockade, which may also reduce proteinuria. The fact that he is severely nephrotic with a serum albumin of 11 g/L raises consideration for anticoagulation prophylaxis, unless contraindicated. We do not have information on serum anti-PLA2R levels and they are crucial in ascertaining probability for spontaneous remission and to guide introduction of immunosuppression (De Vriese, et al. J Am Soc Nephrol. 2017;28(2):421–430). As such, initial therapy in this case should be maximizing conservative therapy with low-sodium and low-protein diet, angiotensin II blockade and blood pressure control.
A 32-year-old woman, presents to the emergency department complaining of bilateral lower limb swelling for 1 week. Her past medical history and review of systems is unremarkable. On physical examination, she has bilateral lower limb swelling extending to the knees. Her blood pressure is 130/65 mm Hg, heart rate is 70 beats/min. Chest and cardiovascular examinations are unremarkable. Her laboratory investigations show, serum creatinine 0.7 mg/dL, serum albumin 10 g/L, Hb 121 g/L, platelets 202 × 10(9)/L, INR and APTT are normal. Urine PCR is ...