Electron Microscopic Findings Can Support Multiple Etiologies of Nephrotoxicity in Renal Tubules

Document Type

Conference Proceeding

Publication Date

9-2020

Publication Title

Archives of Pathology and Laboratory Medicine

Abstract

Context: Electron microscopy (EM) has been mainly used for identifying ultrastructural abnormalities, such as fusion of foot processes and immune complex deposits, in glomeruli. However, EM findings in renal tubules can also provide diagnostic or supportive evidence for final diagnosis. Here, we present multiple situations in which EM can be used to aid diagnosis in various drug-associated nephrotoxicities. Design: Seven cases with drug-induced nephrotoxicity were reviewed, including clinical history, EM findings, and serum creatinine levels, prior to renal biopsy and during follow-up. Results: Two cases with nephrotoxicity by aminoglycoside antibiotics, tobramycin, and gentamycin, showed acute tubular injury with EM findings of myeloid bodies, characterized by laminated dense materials in lysosomes in both proximal and distal tubular epithelium (diagnostic evidence). Four cases of vancomycinassociated nephrotoxicity presented with acute tubular injury and vancomycin casts in distal tubules, characterized by central laminated and surface spikey casts in the lumina of distal tubules (supportive evidence). Vedolizumab, a humanized monoclonal antibody used in treating Crohn disease, can cause T-cell dominant acute interstitial nephritis, with EM revealing lymphocytic infiltration into tubules as tubulitis (supportive evidence). Four of seven cases had renal functional recovery in the follow-up check for serum creatinine (Table). Conclusions: EM findings of characteristic renal tubular changes can be useful as either diagnostic or supportive evidence when correlated with clinical history and etiologies of nephrotoxicity. Therefore, the focus of EM should not only be on glomerular changes, but also on those in the renal tubules.

Volume

144

Issue

9S1

First Page

e88

Comments

Collage of American Pathologists Annual Meeting, October 10-14, 2020, Virtual

Last Page

e88

DOI

10.5858/arpa.2020-0991-AB

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