Osmotic Nephrosis

"Osmotic nephrosis" is a term which describes a common form of renal tubular injury in response to hyperosmolar substances. It is especially relevant to iv contrast nephropathy, and was first observed in animals and human patients infused with hypertonic sucrose. The pattern of injury is shown below (images from a 2008 AJKD review by Dickenmann et al): by both light microscopy and electron microscopy, there is vacuolization and swelling, predominantly along the apical membrane of proximal tubular cells.

In addition to iv contrast nephropathy, the osmotic nephrosis pattern of injury can also occur in response to IVIG, mannitol, and hydroxyethyl-starch ("hetastarch"). It is useful a reversible injury, but not always. Vacuolated cells can be seen in other forms of renal injury (e.g., calcineurin inhibitor toxicity, renal clear cell carcinoma, foam cells) which must be differentiated from osmotic nephrosis.