Evaluation of kidney biopsies in elderly patients

Biopsy-Proven Renal Diseases in the Elderly: A Developing Country Perspective

Renal diseases are one of the common causes of morbidity and mortality in elderly population. Currently, the spectrum of renal diseases in elderly population in our country is unknown. The aim of this study was to determine the pattern of renal diseases in elderly patients in Pakistan. In this retrospective, observational study, we included all consecutive patients aged ≥60 years, on whom native renal biopsies were performed during a period of 25 years from January 1994 to December 2018. The final histologic diagnosis was categorized into four groups, primary glomerular diseases (PGDs), secondary glomerular diseases (SGDs), tubulointerstitial disease (TID), and vascular diseases (VDs). A total of 324 renal biopsies are performed in the study period. The mean age was 64.6 ± 5.1 years, range of 60-80 years with a male-to-female ratio of 3.26:1. The mean serum creatinine at biopsy was 4.1 ± 2.86 mg/dL. Indications for biopsy were acute kidney injury (AKI) in 141 (43.5%), followed by nephrotic syndrome (NS) in 128 (39.5%). Renal disease category was PGD in 204 (63%), SGD in 42 (13%), TID in 58 (17.9%), and VD in 20 (6.1%). Focal segmental glomerulosclerosis (FSGS) is the leading cause of PGD in 55 (27%). Among SGD, amyloidosis was the most common cause in 27 (64.3%). In patients who were biopsied for AKI, majority were crescentic glomerulonephritis accounting for 28 (19.8%). In conclusion, AKI and NS are the common biopsy indications in our population. Overall FSGS is the most common histologic diagnosis in this cohort.

AIN’t got no easy answers: recent advances and ongoing controversies around acute interstitial nephritis

Acute interstitial nephritis (AIN) is a common cause of acute kidney injury that was first described in 1898. It is most commonly caused by drugs and infections, although other aetiologies are implicated. Here we review two papers published in this issue of Clinical Kidney Journal and provide an update on current advances and controversies relating to AIN. Nussbaum and Perazella describe the diagnostic tools (namely urinary and serum biomarkers) available for AIN and highlight that there is no single test that can accurately predict the diagnosis. As such, renal biopsy remains the gold standard. Wendt et al. present findings from a 20-year retrospective study of biopsy-proven AIN. They found that a high degree of inflammation was associated with a greater chance of renal recovery, in contrast to the presence of cortical scars, which were associated with a worse outcome. There was also a significant number who required renal replacement therapy. They advocate the use of a scoring system for AIN to help direct management. We also discuss new drugs associated with AIN (in particular new anticancer drugs) and unusual forms including granulomatous AIN. Finally, we discuss the opportunities for future research and how this may impact clinical practice.