In renal cortical necrosis, which may be patchy or diffuse, bilateral renal arteriolar injury results in destruction of cortical tissues and acute kidney injury Acute Kidney Injury (AKI) Acute kidney injury is a rapid decrease in renal function over days to weeks, causing an accumulation of nitrogenous products in the blood (azotemia) with or without reduction in amount of urine... read more . Renal cortical tissues eventually calcify. The juxtamedullary cortex, medulla, and the area just under the capsule are spared.
Etiology of Renal Cortical Necrosis
Injury usually results from reduced renal artery perfusion secondary to vascular spasm, microvascular injury, or intravascular coagulation.
About 10% of cases occur in infants and children. Pregnancy complications increase risk of this disorder in neonates and in women, as does sepsis Sepsis and Septic Shock Sepsis is a clinical syndrome of life-threatening organ dysfunction caused by a dysregulated response to infection. In septic shock, there is critical reduction in tissue perfusion; acute failure... read more . Other causes (eg, disseminated intravascular coagulation [DIC] Disseminated Intravascular Coagulation (DIC) Disseminated intravascular coagulation (DIC) involves abnormal, excessive generation of thrombin and fibrin in the circulating blood. During the process, increased platelet aggregation and coagulation... read more ) are less common (see table Causes of Renal Cortical Necrosis Causes of Renal Cortical Necrosis ).
Symptoms and Signs of Renal Cortical Necrosis
Gross hematuria, flank pain, and sometimes decreased urine output or abrupt anuria occur. Fever is common, and chronic kidney disease with hypertension develops. However, these symptoms are often overshadowed by symptoms of the underlying disorder.
Diagnosis of Renal Cortical Necrosis
Imaging study or renal biopsy
Diagnosis is suspected when typical symptoms occur in patients with a potential cause.
The diagnosis can usually be established by ultrasonography or CT Computed Tomography Imaging tests are often used to evaluate patients with renal and urologic disorders. Abdominal x-rays without radiopaque contrast agents may be done to check for positioning of ureteral stents... read more . Renal biopsy Renal biopsy Biopsy of the urinary tract requires a trained specialist (nephrologist, urologist, or interventional radiologist). Indications for diagnostic biopsy include unexplained nephritic or nephrotic... read more is done only if the diagnosis is unclear and no contraindications exist. It provides definitive diagnosis and prognostic information.
Urinalysis, complete blood count (CBC), serum electrolytes, liver tests, and renal function tests are done routinely. These tests often confirm renal dysfunction (eg, indicated by elevated creatinine and blood urea nitrogen and by hyperkalemia) and may suggest a cause. Severe electrolyte abnormalities may be present depending on the cause (eg, hyperkalemia Hyperkalemia Hyperkalemia is a serum potassium concentration > 5.5 mEq/L (> 5.5 mmol/L), usually resulting from decreased renal potassium excretion or abnormal movement of potassium out of cells. There... read more , hyperphosphatemia Hyperphosphatemia Hyperphosphatemia is a serum phosphate concentration > 4.5 mg/dL (> 1.46 mmol/L). Causes include chronic kidney disease, hypoparathyroidism, and metabolic or respiratory acidosis. Clinical... read more , hypocalcemia Hypocalcemia Hypocalcemia is a total serum calcium concentration < 8.8 mg/dL (< 2.20 mmol/L) in the presence of normal plasma protein concentrations or a serum ionized calcium concentration < 4... read more ). CBC often detects leukocytosis (even when sepsis is not the cause) and may detect anemia and thrombocytopenia if hemolysis Overview of Hemolytic Anemia At the end of their normal life span (about 120 days), red blood cells (RBCs) are removed from the circulation. Hemolysis is defined as premature destruction and hence a shortened RBC life span... read more , disseminated intravascular coagulation Disseminated Intravascular Coagulation (DIC) Disseminated intravascular coagulation (DIC) involves abnormal, excessive generation of thrombin and fibrin in the circulating blood. During the process, increased platelet aggregation and coagulation... read more (DIC), or sepsis Sepsis and Septic Shock Sepsis is a clinical syndrome of life-threatening organ dysfunction caused by a dysregulated response to infection. In septic shock, there is critical reduction in tissue perfusion; acute failure... read more is the cause. Transaminases may be increased in relative hypovolemic states (eg, septic shock Sepsis and Septic Shock Sepsis is a clinical syndrome of life-threatening organ dysfunction caused by a dysregulated response to infection. In septic shock, there is critical reduction in tissue perfusion; acute failure... read more , postpartum hemorrhage Postpartum Hemorrhage Postpartum hemorrhage is blood loss of > 1000 mL or blood loss accompanied by symptoms or signs of hypovolemia within 24 hours of birth. Diagnosis is clinical. Treatment depends on etiology... read more ). If DIC is suspected, coagulation studies are done. They may detect low fibrinogen levels, increased fibrin-degradation products, and increasing prothrombin time (PT)/INR and partial thromboplastin time (PTT). Urinalysis typically detects proteinuria and hematuria.
Treatment of Renal Cortical Necrosis
Treatment of underlying cause
Preservation of renal function
Treatment is directed at the underlying disorder and at preserving renal function (eg, with early dialysis).
Prognosis for Renal Cortical Necrosis
Prognosis of renal cortical necrosis was poor in the past, with mortality > 50% in the first year. More recently, with aggressive supportive therapy, 1-year mortality can be about 20%, and up to 20% of survivors may recover some renal function.
Renal cortical necrosis is rare, typically occurring in neonates and in pregnant or postpartum women with sepsis or pregnancy complications.
Suspect the diagnosis in patients at risk who develop typical symptoms (eg, gross hematuria, flank pain, decreased urine output, fever, hypertension).
Confirm the diagnosis with renal imaging or renal biopsy.
Treat the underlying disorder.
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