Criteria

Clinical definition[1]

Priapism is defined as a prolonged and persistent penile erection lasting >4 hours, unassociated with sexual interest or stimulation. Stuttering or recurrent priapic episodes may last <4 hours and occur at increasing frequencies.

Pathophysiologic criteria[1][4]

Ischemic priapism

  • Corpus cavernosum testing: blood is hypoxic and dark in color

  • Blood gases: pO₂ <30 mmHg; pCO₂ >60 mmHg; and pH <7.25

  • Color duplex ultrasonography: minimal or absent blood flow.

Nonischemic priapism

  • Corpus cavernosum testing: blood is oxygenated and red

  • Blood gases: pO₂ >90 mmHg, pCO₂ <40 mmHg, and pH of 7.40 (similar to normal arterial blood)

  • Color duplex ultrasonography: blood flow is normal to high in velocity.

Stuttering (recurrent) priapism

  • Corpus cavernosum testing: blood is hypoxic and dark in color

  • Blood gases: pO₂ <30 mmHg, pCO₂ >60 mmHg, and pH <7.25

  • May show defective phosphodiesterase-5 regulatory function in the penis, resulting from altered/dysfunctional nitric oxide and cyclic guanosine monophosphate signaling mechanisms that control erectile function.

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