A 30 year old man presents with generalized edema and hypeension. Urine examination shows subnephrotic proteiria (<2gm)and microscopic hematuria. serum complement levels are decreased and he is positive for antihepatitis Cantibodies. The most likely diagnosis is -

Membranous nephropathy Membranous nephropathy is the most common cause of nephrotic syndrome in Caucasian adults. It is caused by antibodies (usually autoantibodies) directed at antigen(s) expressed on the surface of podocytes, including the M-type phospholipase A2 receptor 1. While most cases are idiopathic, a propoion are associated withother causes, such as heavy metal poisoning, drugs, infections, lupus and tumours . Approximately one-third of patients with idiopathic membranous nephropathy undergo spontaneous remission, one-third remain in a nephrotic state, and one-third develop progressive CKD. High doses of glucocoicoids and cyclophosphamide may improve bboth the nephrotic syndrome and the long-term prognosis. However, because of the toxicity of these regimens, many nephrologists reserve such treatment for those with severe nephrotic syndrome or deteriorating renal function. Treatment of secondary membranous nephropathy is directed at the underlying cause. Ref Harrison20th edition pg 278