Erections lasting longer than 4-6 hours are associated with permanent erection problems. It has been estimated that priapism of 24 hours duration is associated with an approximately 50% incidence of permanent erectile dysfunction. When such a patient presents to their physician's office or the emergency department, a urologist should be notified immediately and urgent steps should be taken to initiate evaluation and treatment. The most important step in evaluating and treating a man with priapism is differentiating between ischemic and non-ischemic priapism.
The patient with ischemic priapism typically complains of a painful erection, which is fully rigid. Men with non-ischemic priapism have an erection that is usually less than fully rigid and painless. The latter patient routinely gives a history of some form of penile or perineal trauma.
A comprehensive history and physical exam should be performed. A history should focus on possible causes, including the use of prescription, erectogenic, or recreational drugs. Formal laboratory testing routinely includes peripheral blood tests, a urine toxicology screen, and a blood gas analysis of the penile blood (corporal blood). Analysis of penile blood gas is paramount in differentiating between ischemic and non-ischemic priapism. Additionally, if the initial evaluation of a man with ischemic priapism is negative, a workup for hematologic malignancies (leukemia, multiple myeloma) or blood dyscrasias (sickle cell disease, thalassemia, and glucose-6-phosphate dehydrogenase) may be undertaken. Occasionally, a penile doppler ultrasound may be used to assess for the presence or absence of penile blood flow and to locate the possible location of a fistula.