Question - What is the pathophysiology underlying contrast associated acute kidney injury?
Answer-The cited article notes “Although the pathophysiological mechanisms by which contrast agents cause kidney injury have not been completely elucidated, direct and indirect effects, as well as hemodynamic perturbations, have been implicated. Contrast agents are directly toxic to tubular epithelial cells, leading to loss of function and both apoptosis and necrosis. Indirect mechanisms are related to ischemic injury due to vasomotor changes mediated by vasoactive substances such as endothelin, nitric oxide, and prostaglandins. The outer renal medulla has a relatively low partial pressure of oxygen, which when coupled with enhanced metabolic demand, makes the medulla particularly susceptible to the hemodynamic effects of contrast material.” (Mehran R et al. Contrast-associated acute kidney injury. 2019 NEJM 380:2146-2155)