Expansion
Hyperfiltration, then microalbuminuria, then proteinuria and decline
Expansion
Stages
- Hyperfiltration: raised GFR, enlarged kidneys, at diagnosis
- Silent: structural change without clinical findings
- Microalbuminuria (incipient): ACR 3 to 30 mg/mmol. The point at which intervention works
- Overt proteinuria: ACR above 30, with declining GFR and hypertension
- End stage renal failure
Histology
- Mesangial expansion
- Basement membrane thickening, the earliest change
- Kimmelstiel-Wilson nodules: nodular glomerulosclerosis, pathognomonic but late
- Hyaline arteriolosclerosis of both afferent and efferent arterioles
“Thickening first, nodules last.”
Management that alters the course: glycaemic control, ACE inhibitor or ARB even if normotensive, SGLT2 inhibitors, blood pressure control, statins and smoking cessation.
Screen annually with an albumin to creatinine ratio on a first morning sample, from diagnosis in type 2 diabetes and from 5 years in type 1.
Consider a non-diabetic cause if there is no retinopathy, an abrupt onset, active urinary sediment with red cell casts, or rapid decline; diabetic nephropathy and retinopathy usually progress together.