Renal disease in the elderly

With advancing age and in the absence of any disease, there is a significant alteration in kidney structure and a gradual decline in renal function. While RPF, GFR, and tubular reabsorptive capacity decrease with age, abnormal signs or symptoms cannot be detected under ordinary circumstances. The aging kidneys, however, have limited capacity to cope with rapid hemodynamic changes or disturbances in fluid and water balance, and this results in signs and symptoms of renal dysfunction. In the elderly, the incidence of primary renal diseases declines while the incidence of renal diseases secondary to systemic disease increases. AGN, while essentially a disease of the young, does occur in the older age group. RPGN, however, is the most common form of acute primary glomerulonephropathy, followed by membranous glomerulonephritis and glomerulosclerosis. Glomerulonephritis secondary to vasculitis and Wegener's granulomatosis and amyloidosis constitutes the most common secondary glomerulonephropathy. Drug-induced acute or chronic tubulointerstitial nephropathy is seen more frequently in the geriatric age group because of the high incidence of multiple-drug treatment. There is a high incidence of ARF in the elderly which is frequently precipitated by hypovolemia, hypotension, nephrotoxic drugs, surgery, and anesthesia. Clinical manifestations of renal disease in the elderly are often atypical and nonspecific. Abnormal signs and symptoms are frequently attributed to extrarenal diseases or to previously existing disorders. For these reasons, renal disease in the elderly may go undetected. Serum creatinine level may remain within normal range despite a drop in GFR because of a reduction in muscle mass with aging. Therefore, creatinine clearance is a more accurate test for assessment of renal function. A decrease in creatinine clearance should not be ignored or attributed to aging; it is an indication for further renal evaluation.