Toxic acute tubular injury describes a lesion with frank necrosis of tubules, which commonly manifests clinically as acute kidney injury, with a rapid decline in glomerular filtration rate, often oliguria, and granular casts and low-level proteinuria. In some settings (eg, with industrial/environmental toxin exposures), the onset may be gradual with a slow decline in glomerular filtration rate and loss of concentrating ability. Toxic acute tubular injury may occur at any age, with varying underlying causality.