Persistent and usually painful erection that lasts for at least four hours in the absence of physical or psychological stimulation, which can be caused by hematologic disorders, including sickle cell disease and leukemia, spinal cord injuries, and medications.

Priapism is a condition in which a penis remains erect for hours in the absence of stimulation or after stimulation has ended. There are three types: ischemic (low-flow), nonischemic (high-flow), and recurrent ischemic (intermittent)...