A review of the pathophysiology,causes and prognosis of acute renal failure in the elderly

This paper reviews some of the pathophysiological, causal and prognostic aspects of acute renal failure (ARF) in the elderly patient. In the discussion on the factors predisposing the aged kidney to acute insults, the hypothesis is advanced that impairment of the autoregulatory capacity of renal blood flow and glomerular filtration rate plays a major role in the pathophysiology of ARF in the elderly patient. Recent data suggest that the relative increase of elderly patients in the overall population of patients with ARF can only partly be explained by the absolute increase of aged people. The major causes of ARF in the elderly are discussed. They show the same spectrum of etiologies of ARF as younger patients but within that spectrum, a significantly higher incidence of acute prerenal failure, iatrogenic hemodynamically-mediated ARF, renal vascular syndromes, glomerulonephritis, and post-ischemic acute tubular necrosis is observed. As far as the severity of the prognosis of ARF in the elderly is concerned, the review of published data does not allow definite conclusions on this subject. The main reason is the lack of information in a form that allows an easy and meaningful comparison. The adoption of scoring systems like the APACHE II system should overcome these problems. At present, the supposition that old age by itself is a bad prognostic factor in the outcome of ARF is dubious and it is certainly not strong enough to deny individual elderly patients with ARF the opportunity of aggressive therapy.