[Etiologic aspects of acute renal insufficiency in the adult]

Acute renal failure (ARF) is a syndrome with numerous underlying causal conditions--upon which depends vital prognosis, and various pathogenetic mechanisms of either functional or lesional nature--upon which depends renal prognosis. Lesions can affect different parts of the renal parenchyma, and may or may not be reversible. Here are described: a) the basic investigations that allow to diagnose both the underlying conditions and the mechanisms of ARF in adults; b) an etiologic classification of ARF. Elements of the renal syndrome, composed of anamnestic, clinical, laboratory, imaging and, if necessary, histological data, have to be gathered in each individual case. Emphasis is laid on some forms of ARF of increasing frequency: ARF induced by angiotensin-converting enzyme inhibitors, rapidly progressive glomerulonephritides, necrotizing vasculitides with circulating antineutrophil cytoplasmic antibodies and hemolytic-uremic syndrome. Early diagnosis of spontaneously non-reversible parenchymal lesions leads to timely etiopathogenic therapy and increases the likelihood of renal anatomical and functional recovery.