Acute Kidney Injury (AKI) is a leading cause of nephrology consultation, associated with high mortality rates. The primary causes include ischemia, hypoxia, and nephrotoxicity, leading to a rapid decline in Glomerular Filtration Rate (GFR) and renal blood flow. Inflammation plays a crucial role in the extension phase of injury, often making patients insensitive to vasodilator therapy. The underlying basis of renal injury involves impaired energetics in highly metabolically active nephron segments, which can trigger conversion from transient hypoxia to intrinsic renal failure. Sublethal injury, while less lethal, significantly influences GFR and renal blood flow, and its recovery is mediated by the ability of sublethal cells to restore normal function and promote regeneration. Successful recovery from AKI depends on the extent of repair processes, which may be compromised in elderly or Chronic Kidney Disease (CKD) patients. Recent data suggest that AKI may represent a potential link to CKD in surviving patients. Early diagnosis of AKI is crucial for effective treatment, and biomarkers of AKI show promise in this regard.Acute Kidney Injury (AKI) is a leading cause of nephrology consultation, associated with high mortality rates. The primary causes include ischemia, hypoxia, and nephrotoxicity, leading to a rapid decline in Glomerular Filtration Rate (GFR) and renal blood flow. Inflammation plays a crucial role in the extension phase of injury, often making patients insensitive to vasodilator therapy. The underlying basis of renal injury involves impaired energetics in highly metabolically active nephron segments, which can trigger conversion from transient hypoxia to intrinsic renal failure. Sublethal injury, while less lethal, significantly influences GFR and renal blood flow, and its recovery is mediated by the ability of sublethal cells to restore normal function and promote regeneration. Successful recovery from AKI depends on the extent of repair processes, which may be compromised in elderly or Chronic Kidney Disease (CKD) patients. Recent data suggest that AKI may represent a potential link to CKD in surviving patients. Early diagnosis of AKI is crucial for effective treatment, and biomarkers of AKI show promise in this regard.