A 45 year old lady presented to her family doctor with symptoms of gastrointestinal reflux. She was started on lansoprazole and immediately felt unwell. A few weeks later she had bloods taken and her creatinine was 880umol/l (10mg/dl0 with an Hb of 6g/dl. Her BMI was 20 and she had a normal blood glucose and calcium. Serum electrophoresis, ANCA, ANA, C3, C4 DsDNA were all normal. She had normal kidney function 6 months ago and had no other medical history.
She was referred urgently for nephrology assessment.
Examination was unremarkable and she was euvolaemic and looked well.
Urine dipstick 1+ protein and no haematuria.
Renal ultrasound was unremarkable and she underwent a kidney biopsy shown below.
The light microscopy shown below was reported as showing nodular glomeruloscelrosis. Electron Microscopy (EM) and immunofluorescence (IF) were awaited.
Renal biopsy below showing nodular lesions and thickened capillary walls on PAS.
Based on the findings above which of the following is the most likely diagnosis?