Cortical necrosis is a rare form of kidney tissue death that affects only part or all of the outer layer (cortex) of the kidney and not the inner layer (medulla). Renal cortical necrosis can occur at any age. About 10% of cases occur in infants and children. More than half of newborns with cortical necrosis are delivered with abrupt placental separation (placental abruption); the other most common cause is bacterial infection of the bloodstream (sepsis). In children, cortical necrosis can be followed by infection, dehydration, shock, or hemolytic uremic syndrome. In adults, bacterial sepsis causes cortical necrosis in about 1/3 of all cases. Distinguishing cortical necrosis from other forms of acute renal failure may be difficult. However, the diagnosis, fever, and leukocytosis should be considered when any of the above clinical conditions present with sudden anuria with granulomatous hematuria and dystocia are common. Even in the absence of sepsis, urine containing many proteins, red and white blood cells, erythrocyte tubularity, renal cell tubularity, and broad tubularity are common. Serum lactate dehydrogenase and glutamate transaminase levels are elevated if measured early. Mild hypertension, or even hypotension, is common in the early stages. However, accelerated or malignant hypertension is typical in patients who have regained partial residual renal function. Definitive diagnosis is made by biopsy showing lamellar or diffuse cortical necrosis. However, renal radiography is useful, showing initially an enlarged kidney in serial radiography. It gradually shrinks, sometimes up to about 50% of normal within 6-8 weeks. At this stage, calcifications appear, often linear, and are particularly evident at the corticomedullary junction. Cortical necrosis can resemble other types of renal failure. The physician should suspect cortical necrosis when there is a sudden decrease in urine output without evidence of ureteral or bladder obstruction or in the presence of conditions causing cortical necrosis, and hematuria is present. Fever is often present. A slight increase in blood pressure or hypotension is also common. The small amount of urine produced contains protein, a large number of red blood cells with leukocytes and tubular patterns (clumps of red blood cells, white blood cells and other debris). Levels of certain enzymes that can be measured in the blood can be abnormally high in the early stages of the disease.