When is renal biopsy recommended in patients with a long-standing history of diabetes mellitus and nephrotic proteinuria?
Jürgen Floege: Normally, if you are diabetic and you go through all the usual stages – that is, you develop microalbuminuria, then some proteinuria, then you become nephrotic – it usually takes a while. Usually, by the time the patients are nephrotic, their kidney function is going down. I would become suspicious and do a kidney biopsy if the patient is nephrotic with normal kidney function or if nephrotic syndrome develops very quickly. Then the suspicion is that you have other disease than diabetes.