[Old age and the kidneys]

Age-related changes in renal morphology and function cannot be regarded physiological. The number of glomeruli falls, sclerotic glomeruli and aglomerular arterioles develop. Besides tubular atrophy interstitial fibrosis is often seen, and the age-related vascular changes strongly affect the kidneys. Renal blood flow and GFR decrease, without concomitant changes in se-creatinine. Disorders of tubular transport manifest mainly in salt- and water-excretion and lead to hyposthenuria. The pathogenesis of these age-related changes is not fully understood. Nevertheless, such changes impair the excretory functions and the pharmacokinetics of drugs. In real chronic renal failure other functions (erythropoietin production, vitamin-D, Ca and P metabolism) are also impaired. Due to more frequent occurrence of systemic diseases (diabetes, hypertension, etc.) in the elderly, real chronic renal failure is also more common, and various forms of acute renal failure develop more easily.