Renal disease. I.

It is of course impossible in an article of this length to review all the growing points in the study of renal disease at the moment.My choice has been to discuss, first, advances in the fields of acute and chronic renal failure ; and then to consider nephritis, the nephrotic syndrome, and related topics.Recent progress has rested largely on two factors.First, technical advances, which have enabled the principle of dialysis to be applied to treating acute and chronic renal failure.Another major technical advance has been the exploitation of safe biopsy of the kidney.The second factor has been the application to clinical medicine of biochemical and physiological knowledge, particularly the former.No other branch of medicine is at the moment so dependent for its daily conduct upon applied biochemistry as the study of renal disease. Acute Renal FailureImmediately after the second world war over 90 % of patients with acute renal failure died.Now only about one-quarter of such patients die.The mortality today reflects mainly the general condition of the patient and the precipitating causes.Renal ischaemia, trauma, hypotension, septicaemia, haemo- globin circulating free in the blood-stream, jaundice, hypoxia, and various chemicals toxic to the renal tubular cells are all known to precipitate acute renal failure, and are additive in their effect on the kidney.Young patients have a better prog- nosis than the aged, and obstetric patients or those with acute renal failure due mainly to nephrotoxic substances usually recover.But patients with severe trauma, hypotension, or infection-such as battle casualties and other accidents-or those with post-operative complications, still have a mortality rate of over 50%.Recent studies of the functional disturbances in acute renal failure and the histological appearance of the kidney have shown a striking contrast: the almost complete cessation of function is associated with very few obvious changes.The glomeruli appear nearly normal, and tubular necrosis, if present, is often patchy or slight.Originally this tubular necrosis was thought to be the common or dominant lesion in acute renal failure, and now that it is known to be somewhat rare the simple descriptive term "acute renal failure " is used for this group of patients.Though the blood-flow through the kidney at the beginning of renal failure may be low, when the patient is first seen it is found to be considerable, even if there is com- plete anuria.Examination of the urine shows that, while tubular function is far from normal, the glomerular filtrate which is being formed is being considerably modified by the tubules.Whether the lesion in acute renal failure is glomerular, and how it comes about, are still unknown.