A 64-year-old male presents with a
history of fever and swelling of his body. He gives a history of taking
diclofenac for pan relief from osteoarthritis. On examination his face looks
puffy and he has ankle oedema. . His blood pressure is 210/110 mm Hg. Urine
show s heavy proteinuria. 24-hour urine proteins 3.7 g/24 hours. His serum
albumin is 24 g/'L
Which of the following is likely to
have caused his present condition?