Saying "without urine retention" makes it clear that retention issue is ruled out and no longer ddx
Zero output -> mechanical issue
Low output
1. Bladder scan, if high, it is a retention issue and CIC
2. If low, do saline bolus. If improves, it is prerenal/underperfusion.
3. If it fails to improve, it is AKI/ATN
Please resubmit with an acceptable source. Acceptable sources include specific UWorld QIDs + copied explanation, specific amboss article links with copied text for rationale, specific FA 2023 page numbers, and other cards in the deck (list specific nid #). Screenshots of sources via Imgur are helpful. Unacceptable sources include FA 2022 or older, Pathoma, B&B, Sketchy, random articles, and wikipedia.