Changing picture of renal cortical necrosis in acute kidney injury in developing country.

Renal cortical necrosis (RCN) is characterized by patchy or diffuse ischemic destruction of all the elements of renal cortex resulting from significantly diminished renal arterial perfusion due to vascular spasm and microvascular injury. In addition, direct endothelial injury particularly in setting of sepsis, eclampsia, haemolytic uremic syndrome (HUS) and snake bite may lead to endovascular thrombosis with subsequent renal ischemia. Progression to end stage renal disease is a rule in diffuse cortical necrosis. It is a rare cause of acute kidney injury (AKI) in developed countries with frequency of 1.9%-2% of all patients with AKI. In contrast, RCN incidence is higher in developing countries ranging between 6%-7% of all causes of AKI. Obstetric complications (septic abortion, puerperal sepsis, abruptio placentae, postpartum haemorrhage and eclampsia) are the main (60%-70%) causes of RCN in developing countries. The remaining 30%-40% cases of RCN are caused by non-obstetrical causes, mostly due to sepsis and HUS. The incidence of RCN ranges from 10% to 30% of all cases of obstetric AKI compared with only 5% in non-gravid patients. In the developed countries, RCN accounts for 2% of all cases of AKI in adults and more than 20% of AKI during the third trimester of pregnancy. The reported incidence of RCN in obstetrical AKI varies between 18%-42.8% in different Indian studies. However, the overall incidence of RCN in pregnancy related AKI has decreased from 20%-30% to 5% in the past two decades in India. Currently RCN accounts for 3% of all causes of AKI. The incidence of RCN in obstetrical AKI was 1.44% in our recent study. HUS is most common cause of RCN in non-obstetrical group, while puerperal sepsis is leading cause of RCN in obstetric group. Because of the catastrophic sequelae of RCN, its prevention and aggressive management should always be important for the better renal outcome and prognosis of the patients.