What are the histopathologic lesions associated with acute phosphate nephropathy?
The hallmark of acute phosphate nephropathy is abundant tubular and less prominent interstitial calcium phosphate deposits.
Greater than 30 calcifications and sometimes greater than 100 calcifications per tubular profile may be seen.
The calcifications form basophilic rounded concretions, are mainly confined to the distal tubules and collecting ducts, and are prominent in the kidney cortex.
The calcifications do not polarize and have a strong histochemical reaction with the von Kossa stain, indicating that they are composed of calcium phosphate. Acute tubular degenerative changes and interstitial edema are seen with early lesions.
Biopsies performed more than 3 weeks after exposure to sodium phosphate exhibit chronicity (tubular atrophy/interstitial fibrosis).
Acute and/or chronic tubulointerstitial nephropathy, reminiscent of changes seen in nonresolving acute tubular necrosis (ATN), may be present.
There may also be an association between PPI’s and hyponatremia via SIADH. But due to the paucity of data and the many confounding variables, causation has not been demonstrated.