Background: Renal cortical necrosis (RCN) accounts for 2% of all cases of acute renal failure (ARF) in adults and 15-20% of ARF during the third trimester of pregnancy in developed nations. However, RCN incidence is higher in developing countries ranging from 6-7% of all cases of acute renal failure. The present study describes changing trends in the clinical spectrum of RCN in patients with ARF in Eastern India.
Methods: Patients with ARF suspected to have RCN on clinical grounds underwent percutaneous renal biopsy. Patients showing cortical necrosis on histology were included in the present study. Diffuse and patchy cortical necrosis was classified based on standard histological criteria. The patients with cortical necrosis were studied over a period of 22 years; from July 1984 to December 2005. The results of our observation were compared with respect to etiology, incidence, prognosis and outcome of renal cortical necrosis in two study periods; namely, 1984-1994 and 1995-2005.
Results: The incidence of RCN was 3.12% of all cases of ARF of diverse etiology. RCN was observed in 57 patients; obstetric 32 (56.2%); non-obstetric 25 (43.8%). Diffuse cortical necrosis was the dominant lesion in 41 (71.9%) patients and the remaining 16 (28%) patients had patchy cortical necrosis. The overall incidence of RCN in obstetric ARF was 15.2%; the incidence being higher (11.9%) in the post-abortal group in comparison to 3.3% in late pregnancy. RCN had occurred complicating abruptio placentae, puerperal sepsis and postpartum haemorrhage (PPH) in late pregnancy, while septic abortion was the sole cause of RCN in early pregnancy. Haemolytic uraemic syndrome (HUS) was the major (31.5%) cause of RCN in the non-obstetric group and miscellaneous factors were responsible in seven (12.3%) patients. Partial recovery of renal function was observed in 11 (19.2%), and 16 (28%) patients had progressed to ESRD. The incidence of RCN decreased from 6.7% in 1984-1994 to 1.6% in 1995-2005 of total ARF cases. RCN following obstetrical complication decreased significantly; 4.7% in the 1990s to 0.5% of the total ARF cases, in the 2000s. The mortality decreased to 19% in 1995-2005 from the initial high mortality of 72% in 1984-1994. The renal prognosis improved as a result of the decreased mortality of patients.
Conclusion: We observed a decreasing trend in the incidence of RCN in patients with ARF in recent years, which is associated with increased patient survival and better renal prognosis. This improvement was mainly due to declining incidence and severity of RCN in obstetrical ARF.