Priapism Differential Diagnoses

Updated: Jan 25, 2023
  • Author: Osama Al-Omar, MD, MBA, FACS, FEBU; Chief Editor: Edward David Kim, MD, FACS  more...
  • Print

Diagnostic Considerations

The diagnosis of priapism may be straightforward, depending on the physical findings. Pathologic states associated with priapism give rise to the differential diagnosis. Some of the major considerations are as follows:

  • Intracavernosal agents used to treat erectile dysfunction
  • Oral agents used to treat erectile dysfunction
  • Genitourinary trauma
  • Medications
  • Cocaine
  • Spinal stenosis
  • High spinal cord injury
  • Urethral foreign body
  • Penile surgical implant
  • Erection from sexual arousal

Low-flow versus high-flow priapism

To provide appropriate treatment, physicians must differentiate between low-flow and high-flow priapism. This is accomplished by taking a thorough history, performing a careful physical examination, and measuring the oxygen content of blood within the corpora cavernosa by penile blood gas (PBG) analysis (see Workup).

Low-flow priapism, which constitutes the large majority of cases, is characterized by a rigid, painful erection; ischemic corpora, as indicated by dark blood upon corporeal aspiration; and no evidence of trauma. The history may reveal an underlying cause, such as sickle cell disease or use of intracavernosal or oral agents for treatment of erectile dysfunction, or other medications known to be associated with priapism (see Etiology).

Patients with high-flow priapism typically have a history of blunt or penetrating trauma to the penis or perineum, resulting in a fistula between a cavernosal artery and the corpus cavernosum. Clinically, high-flow priapism is characterized by a painless erection; tumescence is typically less marked than in low-flow priapism.

The presence of bright red blood during aspiration is a helpful but not pathognomonic finding of high-flow priapism. PBG findings approximate normal arterial values. Penile duplex ultrasonography with angiographic confirmation helps to identify and locate these fistulae.