Acute kidney injury in severe sepsis

Septic acute kidney injury (S-AKI) accounts for close to 50% of all cases of AKI in ICU and, in its various forms, affects between 15% and 20% of ICU patients. Patients typically present with clinical evidence of severe sepsis and septic shock, developing oliguria or anuria, and rapidly rising serum creatinine concentration. The pathophysiology of S-AKI is poorly understood. Although haemodynamic factors might play a role in the loss of glomerular filtration rate, this may not be through the induction of renal ischaemia. Inflammation, microvascular shunting, and changes in glomerular arteriolar tone may play important roles. Much evidence suggests that clinically urinalysis fails to provide useful diagnostic or prognostic information in this setting but novel biomarkers and urine microscopy may provide more useful prognostic information.The treatment of S-AKI remains based on the treatment of the aetiology of sepsis with source control and appropriate antibiotics, supportive treatment of systemic illness including, in severe cases, renal replacement therapy (RRT). Because most patients with S-AKI requiring RRT are critically ill and haemodynamically unstable, RRT in these patients is best provided as continuous RRT.Approximately 50% of patients with severe S-AKI survive to hospital discharge and, among those who survive, approximately 85–90% recover to dialysis independence. However, those patients who recover appear to be at increased risk of developing chronic kidney disease over the following years.