Urogenital ImagingPriapism
a spontaneous, prolonged usually painful penile erection that results from abnormal regulation of penile flaccidity that can last from several hours up to a few days. Named after Priapus, the Greek god of fertility, this condition is seen when blood that flows into the penis during erection is unable to drain.
In most cases, priapism results from drugs or medical conditions. Penile injections used to treat some forms of impotence can cause priapism, particularly when an excess dose is self-administered by the patients. Psychiatric medication, such as antidepressants, can cause priapism; however, their mode of action remains unclear. Drugs most commonly associated with priapism include trazodone and chlorpromazine.
High-flow or arterial priapism results from increased arterial inflow into the cavernosal sinusoids, overwhelming venous outflow. This may cause a painless semirigid to rigid erection. Causes of high-flow priapism include idiopathic aetiologies and groin or saddle trauma resulting in pudendal artery damage.
Assessment of priapism includes a detailed history and a physical examination. A complete blood count and a sickle cell preparation may be indicated.
If the cause of priapism is unclear, penile or perineal Doppler ultrasonography may be used to check for arteriocavernosal fistulae or high systolic flow into the cavernosal artery, both of which are diagnostic of high-flow priapism.
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