Acute kidney injury is a heterogeneous group of conditions characterized by a sudden decrease in glomerular filtration rate, manifested by an increase in serum creatinine concentration or oliguria, and classified by stage and cause. This type of injury occurs in approximately 20% of hospitalized patients, with major complications including volume overload, electrolyte disorders, uremic complications, and drug toxicity. Management includes specific treatments according to the underlying cause and supportive treatment to prevent and manage complications. Kidney replacement therapy is used when complications cannot be managed with medical therapy alone. Despite advances in care, the mortality rate in patients requiring kidney replacement therapy remains approximately 50%.