[Diagnostic procedure for acute kidney failure]

A diagnostic procedure for acute kidney injury. The definition of acute kidney injury (AKI) is universal since 2011. It is simple, based on the increase in serum creatinine on a short time period. AKI may be life-threatening, which is why the priority is to rule out hyperkalemia, pulmonary edema, or severe acidosis. Then, a panel of clinical, biological and radiological analyses is required to establish the mechanism of AKI and treat it appropriately. Basically, a three steps process is suggested: an obstruction of the urinary cavities is looked for; circumstances of renal hypoperfusion are considered, and urinary electrolytes measured; by elimination, a diagnosis of parenchymal AKI is eventually made. In that case AKI is in most cases due to an acute tubular necrosis, which implies to collect positive and negative signs: a recent history of hypotension, intake of toxic drugs, etc.; proteinuria should be low, i.e. less than 1 g/L, and urinary cells in normal count. In the presence of extra-renal symptoms, and of urinary abnormalities such as abundant proteinuria and hematuria or leucocyturia, a specialized care is urgently needed and a renal biopsy often indicated.