What causes priapism?

Updated: Dec 26, 2019
  • Author: Osama Al-Omar, MD, MBA, FACS, FEBU; Chief Editor: Edward David Kim, MD, FACS  more...
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Priapism can be idiopathic or can be secondary to a variety of diseases, conditions, or medications. In the United States, the most common cause of priapism in the adult population involves agents used to treat erectile dysfunction. Internationally, most cases are idiopathic.

The most common cause of priapism in the pediatric population is sickle cell disease (SCD), which is responsible for 65% of cases. Leukemia, trauma, and idiopathic causes are the causes in 10% of patients. Pharmacologically induced priapism is the etiology in 5% of children. [8] Among the secondary causes of low-flow priapism are the following thromboembolic/hypercoagulable states:

  • Sickle cell anemia - One study found that, in unscreened children with SCD, priapism was the first presentation in 0.5% of cases [4]
  • Dialysis
  • Vasculitis
  • Fat embolism (from multiple long-bone fractures or intravenous infusion of lipids as part of total parenteral nutrition)

Neurologic diseases that can result in low-flow priapism include the following:

  • Spinal cord stenosis (ie, trauma to the medulla)
  • Autonomic neuropathy and cauda equina compression

Neoplastic disease (metastatic to the penis or obstructive to venous outflow) that can result in low-flow priapism include the following [9] :

  • Prostate cancer
  • Bladder cancer (highest risk)
  • Hematologic cancer (leukemia)
  • Melanoma

Pharmacologic causes of low-flow priapism include the following:

  • Intracavernosal agents - Papaverine, phentolamine, prostaglandin E1
  • Intraurethral pellets (ie, medicated urethral system for erection with intracavernosal prostaglandin E1)
  • Antihypertensives - Ganglion-blocking agents (eg, guanethidine), arterial vasodilators (eg, hydralazine), alpha-antagonists (eg, prazosin), calcium channel blockers
  • Psychotropics - Phenothiazine, butyrophenones (eg, haloperidol), perphenazine, trazodone, selective serotonin reuptake inhibitors (eg, fluoxetine, sertraline, citalopram) [5]
  • Anticoagulants - Heparin, warfarin (during rebound hypercoagulable states)
  • Recreational drugs - Cocaine [10]
  • Hormones - Gonadotropin-releasing hormone (GnRH), tamoxifen, testosterone, androstenedione for athletic performance enhancement
  • Herbal medicine - Ginkgo biloba with concurrent use of antipsychotic agents [11]
  • Miscellaneous agents - Metoclopramide, omeprazole, penile injection of cocaine, epidural infusion of morphine and bupivacaine [12]

Only rare case reports have associated phosphodiesterase-5 enzyme inhibitors such as sildenafil with priapism. In fact, several reports suggest sildenafil as a means to treat priapism and as a possible means of preventing full-blown episodes in patients with sickle cell disease. [13]

High-flow priapism may result from the following forms of genitourinary trauma:

  • Straddle injury
  • Intracavernous injections resulting in direct cavernosal artery injury

Rare causes of priapism include the following:

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