American Urological Association - Renal Cortical Necrosis
Renal Cortical Necrosis
- Usually bilateral, diffuse or multifocal kidney involvement and results from an extrarenal process.
- Most commonly encountered as an obstetrical complication (50-60%), such as abruptio placenta, placenta previa.
- Other causes include gram- septicemia (30-40%) (E. coli, K. pneumonia), and rarely, toxicity, shock due to ketoacidosis, acute pancreatitis, burns, acute blood loss.
- Normally renal blood flow is 80% cortex and 20% medulla; increase susceptibility to ischemic insults.
- Outer rim of renal capsule spared because capsular vessels supply it.
- Presents with prolonged decrease or absent urine output, flank pain, gross hematuria.
- 20% of ARF in pregnancy is due to cortical necrosis; high fatality also from extrarenal cause.
- ~1/2 eventually develop CRF.
- Early phase shows yellow discoloration of cortex (hemorrhagic if blood supply is reestablished) and subcapsular and juxtamedullary congestion.
- Late phase shows cortical fibrosis with thinning and calcifications.
- Widespread coagulative necrosis (preserve ghost cell outlines) of cortex (image B).
- Subcapsular (1-2mm) and medulla spared from the process.
- Tubules in non-necrotic area may have acute tubular injury and thrombi may be seen in vessels including glomeruli.