Topic Discussion: COVID and Kidneys- the biopsy experience

As we expand our understanding of COVID-19 related AKI, in the last few weeks, more studies are emerging on what might be the main kidney biopsy findings with COVID related AKI.
We have now established the incidence being around 30-40% in the US.

What is exactly going on in the kidney? Is the virus attacking the kidney or is the renal disease a consequence of "being sick" and or  "inflammatory state".

This figure from an article in JASN summarizes the potential way the SARS-Cov2 might be effecting the kidney



Two recent biopsy series from Columbia and Northwell Nephrology showed the variety of pathology reported in COVID-19



In addition, an autopsy series (specific) to the kidneys showed ATN only.  Finally, in KI, a series of anti GBM were reported in UK related to COVID-19

All recent papers added interesting few things to the ongoing literature.

1. ATN is by far the most common presentation for AKI( if not pre renal)- even in transplanted kidney. Pigment nephropathy from myoglobin or hemoglobin is rare. Vitamin C overdose induced oxalate nephropathy is rare.
2. Podocytopathies( MCD and cGN) are the most common glomerular findings
3. Other glomerular diseases are a varied amount( TMA, ANCA, Membranous GN, anti GBM)
4. The virus was not found in the kidney with immunohistochemistry in all 3 studies.

Does the kidney get infected?- time will tell.. data is mixed