Diagnosis and Management of Prolonged Penile Erection
Priapism, a spontaneous, prolonged, usually painful penile erection, results from abnormal regulation of penile flaccidity. Harmon and Nehra review the diagnosis and management of different types of priapism.
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. Damage to cells is rare because of high oxygenation. Causes of high-flow priapism include idiopathic etiologies and groin or saddle trauma resulting in pudendal artery damage. Management of high-flow priapism is elective.
In the flaccid state, vascular inflow is limited because of resistance caused by contracted cavernous arterial branches and sinuses. Neurotransmitters or vasoactive substances relax smooth muscles, with decreased compliance resulting in minimal resistance to incoming blood flow. Expansion of the sinusoidal walls inhibits venous outflow, and an erection occurs.
Assessment of priapism includes a detailed history and a physical examination, observing the penile shaft for rigidity and pain. A complete blood count and a sickle cell preparation may be indicated. Medications most commonly associated with priapism include trazodone and chlorpromazine. Urologists treating erectile dysfunction with intracavernosal drug therapy using papaverine, phentolamine and prostaglandin E1 may see an increased number of cases of priapism.
Management of priapism in sickle cell disease requires analgesia, hydration, oxygen and red cell exchange transfusion. Surgical shunting may be performed if needed. Management of idiopathic priapism is described in the accompanying figure on page 920. If the cause of priapism is unclear, penile or perineal Doppler ultrasonography may be used to check for arterial-to-cavernosum fistula or high systolic flow into the cavernosal artery, both of which are diagnostic of high-flow priapism. A pH of less than 7.25 in aspirated blood with a partial pressure of oxygen less than 30 mm Hg are suggestive of low-flow priapism.
The authors conclude that timely management can restore full potency to most patients with priapism.--Richard L. Sodovsky, M.D.