priapism

Priapism is a prolonged penile erection lasting more than four hours that persists without sexual stimulation or after incomplete detumescence. It is considered a urological emergency because prolonged erection can cause tissue damage and permanent erectile dysfunction if not treated promptly.

There are three main forms of priapism. Ischemic (low-flow) priapism is the most common and is caused by impaired venous outflow leading to tissue hypoxia, acidosis, and pain. Nonischemic (high-flow) priapism results from unregulated arterial inflow, usually due to pelvic or penile trauma, and is typically less painful and not associated with tissue hypoxia. Stuttering (recurrent) priapism consists of repeated, self-limiting episodes of erection, often with periods of detumescence in between.

Causes vary by type. Ischemic priapism is associated with hematologic conditions such as sickle cell disease or other anemias, penile or pelvic injuries, certain medications (including trazodone, some antidepressants, antipsychotics, and illicit drugs), and dehydration or alcohol use. Nonischemic priapism can follow penile or pelvic trauma, fistula formation, or arterial injuries. Stuttering priapism is commonly linked to sickle cell disease and repeated episodes of ischemia.

Diagnosis relies on history and physical examination, supported by objective tests. Ischemic priapism typically presents with a painful, rigid erection; nonischemic priapism often presents as a more flexible, painless erection. Penile blood gas analysis showing low oxygen and high carbon dioxide with acidosis supports ischemia; Doppler ultrasound assesses blood flow and helps distinguish the two forms.

Management differs by type. Ischemic priapism requires urgent intervention to restore venous outflow: bedside aspiration of blood from the corpora cavernosa, irrigation with saline, and injection of alpha-adrenergic agents such as phenylephrine; remaining cases may require surgical shunting. Treat underlying causes (eg, hydration and transfusion for sickle cell disease). Nonischemic priapism is usually observed if stable, with intervention reserved for persistent or bothersome cases, potentially including selective arterial embolization or surgery. Stuttering priapism is managed to prevent recurrences and often involves addressing underlying conditions and, in some cases, preventive medications. The prognosis improves with prompt treatment, while delays increase the risk of erectile dysfunction.