The image quiz from 12/28/11 shows muddy brown or deeply pigmented casts in a patient with acute tubular necrosis (ATN).
While the classic urinary sedimentary finding in a patient with ATN are muddy brown casts, this is not always so. In my experience, a good history suggestive of ATN and one or more of the 5 "faces" of ATN can also be seen. The 5 faces of ATN are below:
1. Bland sediment
2. Renal tubular epithelial cells
3. Renal tubular epithelial cell cast
4. Finely granular casts
5. Muddy brown casts with necrotic debris
