A 50 year old Chinese man presents for a routine evaluation. He has had poorly controlled type 2 diabetes mellitus for 10 years, complicated by retinopathy & distal symmetric polyneuropathy. His labs show an HbA1c of 9.0%, normal electrolytes, and a serum creatinine of 1.6 mg/dl with an eGFR of 46 mL/min/1.73 m2. Six months ago, the creatinine was 0.8 mg/dl, with no microalbuminuria. There were no urinary symptoms, and there is no family history of renal disease.
Appearance: turbid Protein: +++ RBC: 8/hpf (0-3) dysmorphic cells noted WBC: 2/hpf (<2) erythrocyte and leukocyte casts present
Urine protein:creatinine ratio > 3.0 (normal: <0.2)
The ultrasound scan demonstrates a left kidney of 9.8 cm and a right kidney of 10.1 cm, both of which show increased cortical echogenicity. The urinary tract appears normal with no evidence of obstruction, cysts or anatomic abnormalities.
Several glomeruli show mesangial hypercellularity compatible with IgA nephropathy superimposed on diabetic nephrosclerosis. Immunofluorescence microscopy shows IgA deposits diagnostic of IgA nephropathy.