[For or against renal biopsy after 65 years].

Kidney biopsy (KB) is controversial in the elderly because it is generally felt that the risks exceed the potential therapeutic benefits. In this review of our personal experience and the literature reports, we discuss the risks of this diagnostic procedure and its use in the four main circumstances of patient referral. On the one hand, KB does not seem to be more hazardous in the elderly, provided that it is not performed in patients in poor condition or with atrophic kidneys or suspected vascular lesions. On the other hand, KB is clearly useful in a number of elderly patients either to assess the diagnosis of a systemic disease involving the kidney or to select the appropriate treatment. 1. In patients with non nephrotic proteinuria, KB should be performed if the proteinuria is associated with extra-renal signs suggestive of systemic disease or with deterioration of renal function. 2. Nephrotic syndrome without evidence of amyloidosis and diabetes, should lead to KB to identify patients with minimal change disease (MCD) requiring steroid treatment. Indeed, MCD can rarely be suspected on clinical grounds as the resulting nephrotic syndrome is rarely "pure" at this age. 3. In acute renal failure, KB seems to be essential and urgent in patients with rapidly progressive glomerulonephritis and in those with renal failure of dubious origin to select the most appropriate treatment according to the etiology and the type of renal lesions (sclerotic or "active"). 4. KB is useless and hazardous in chronic renal failure, except in case of unexplained rapid worsening of renal function in patients with previously moderate renal failure.