ABSTRACT
It is not always possible to judge in a uraemic individual whether the problem is acute or chronic. Pointers towards chronicity include the clinical history, presence or absence or anaemia (chronic renal failure is often associated with anaemia) and the size of the kidneys on imaging (small kidneys signify chronicity, normal-sized kidneys may be affected by acute or chronic renal failure; very large, polycystic kidneys, if seen, would of course suggest a chronic problem). Patients with chronic renal disease may develop superimposed acute renal tubular necrosis or other causes of acute deterioration in kidney function and indeed are more prone to do so in some situations, for example after exposure to iodine-containing contrast media.
