Acute interstitial nephritis in the elderly: a report from the UK MRC Glomerulonephritis Register and a review of the literature.

Acute interstitial nephritis is an uncommon renal disorder, causing 2–3% of episodes of acute renal failure Results [1,2]. There are no specific clinical features, and a high index of suspicion together with a readiness to perform The register contained information on 7161 renal renal biopsy in all cases of unexplained renal failure is biopsies in adult patients, 5347 in patients aged <60 required to confirm the diagnosis. Identification of years and 1814 in patients aged 60 years. Of these, interstitial nephritis is not trivial, as prompt recognition 425 (5.9%) demonstrated interstitial nephritis. Isolated and removal of the precipitating cause usually leads to interstitial nephritis was present in 160 (2.2% of all complete recovery of renal function. Interstitial nephbiopsies), and associated interstitial nephritis in 265 ritis may occur at any age, but may be more frequent (3.7% of all biopsies). Interstitial nephritis (both total in the elderly [3]. This could reflect an increased number and number with isolated interstitial nephritis) exposure to aetiological agents, an increased susceptiwas a more common biopsy finding in the older age bility to interstitial nephritis or a greater sensitivity of group (total: 8.8 vs 5.0%, P<0.001; isolated 3.0 vs ageing kidneys, with already diminished function. To 1.9%, P<0.01). Acute renal failure had been a feature investigate the incidence and clinical features of this at presentation in 1172 biopsies, of which 76 demondisorder in the elderly, we have undertaken a review strated isolated interstitial nephritis (6.5%). In the of all cases of interstitial nephritis from the UK MRC cases where acute renal failure had been the presenting Glomerulonephritis (GN) Register [4]. clinical feature, isolated interstitial nephritis was identified in 6.5% of patients aged <60 years and in 6.4% of those aged >60 years. Method