Acute scrotal pain.

The diagnosis of acute scrotal pain can be difficult. The most common causes include torsion of a testicular appendage, epididymitis, and testicular torsion, which account for 85% to 90% of all cases. These entities may be clinically indistinguishable because characteristic symptoms and signs for each overlap, whereas pathognomonic features are uncommon. Diagnostic accuracy without delay is required to avoid the loss of testicular function in testicular torsion cases and to avoid unnecessary surgery in other cases. A thorough understanding of the key clinical features of each entity, coupled with an understanding of the appropriate use of perfusion imaging studies, will equip the emergency physician with the tools to accomplish this task.