History
Patients with priapism report a persistent erection. Accompanying symptoms depend on the type of priapism and the duration of engorgement. Low-flow, ischemic-type priapism is generally painful, although the pain may disappear with prolonged priapism.
High-flow, nonischemic priapism is almost never painful. This type of priapism is associated with blunt or penetrating injury to the perineum. It may manifest in an episodic manner.
Points to address in the history are as follows:
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Duration of erection (longer than 4 hours is consistent with priapism)
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Duration of pain
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Similar prior episodes (ie, stuttering priapism)
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Genitourinary (GU) trauma
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Medical history (eg, sickle cell disease [SCD]): Onset occurs during sleep, when relative oxygenation decreases
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Medication and/or recreational drug use, especially the antidepressant trazodone, intracavernosal injections of prostaglandin E1 used to treat impotence, and illicit cocaine injection into the penis
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History of malignancy (eg, prostate cancer, bladder cancer)
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Penile prosthesis: The permanent erection that occurs with some penile prostheses may mimic priapism
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Recent urologic surgery
Historical features of low-flow priapism include the following:
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Painful
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Patient is inactive sexually and without desire
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No history of trauma
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Patient usually presents to emergency department (ED) within hours
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Often associated with substance abuse or vasoactive penile injections
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Rare causes include leukemia, fat embolism, acute spinal cord injury, or (extremely rare) cancer metastases to the corporeal bodies
Historical features of high-flow priapism include the following:
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Not painful
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The patient may be sexually active
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Straddle injury usually the initiating event
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Chronic recurrent presentation
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Generally not caused by medication
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Delay may exist between the initiating injury and the onset of priapism (eg, because of initial vessel spasm or to the formation of a clot that is gradually reabsorbed over a period of days)
Physical Examination
Obvious erection is the key physical finding in any case of priapism. Penile priapism generally involves only the paired corpora cavernosa, with the glans and corpora spongiosum remaining flaccid or softly distended without rigidity. Careful physical examination may reveal specific causal factors. Remember that no single pathology excludes all others; therefore, a thorough history and physical examination should address the patient as a whole.
Points to address in the physical examination are as follows:
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Penile color, rigidity, and sensation (soft glans vs firm glans)
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Penile discharge, lesions, or both
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Evidence of local trauma or injection sites
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Presence of prosthetic devices (hardware malfunction may cause pseudopriapism)
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Regional lymphadenopathy (ie, metastatic disease)
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Rectal tone: High spinal cord lesions or stenosis may cause priapism
Aspects of the physical examination consistent with low-flow priapism are as follows:
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Rigid erection
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Ischemic corpora as indicated by dark blood upon corporeal aspiration
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No evidence of trauma
Aspects of the physical examination consistent with high-flow priapism are as follows:
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Adequate arterial flow
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Well-oxygenated corpora
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Evidence of trauma
In young children, the presence of the Piesis sign (prompt detumescence upon perineal compression with the examiner’s thumb) indicates high-flow priapism.
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Priapism. Corporeal relaxation causes external pressure on the emissary veins exiting the tunica albuginea, trapping blood in the penis and causing erection.
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Priapism. Sexual stimulation causes the release of nitric oxide (NO) via stimulation of nonadrenergic noncholinergic neurons. NO-activated intracellular guanylate cyclase, converting guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP), causes relaxation of cavernosal arteries and increased penile blood flow, resulting in erection.
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Priapism. Winter shunt placed by biopsy needle, usually under local anesthetic.
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Priapism. Proximal cavernosal-spongiosum shunt (Quackel shunt) surgically connects the proximal corpora cavernosa to the corpora spongiosum.
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Priapism. Proximal cavernosal-saphenous shunt (Grayhack shunt) surgically connects the proximal corpora cavernosum to the saphenous vein.
