Priapism Workup

Updated: Nov 28, 2016
  • Author: Hosam S Al-Qudah, MD; Chief Editor: Edward David Kim, MD, FACS  more...
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Workup

Approach Considerations

A complete blood cell count (CBC) should be performed to determine whether the patient has anemia, leukocytosis, or thrombocytosis. Rarely, the CBC will identify undiagnosed leukemia as the cause of priapism.

Patients with sickle cell disease should have a CBC and a reticulocyte count. If sickle cell status is unknown, a hemoglobin S determination may be useful. Patients with sickle cell disease may also need a blood type and screen performed in case transfusion or plasma exchange is necessary.

Measurement of plasma thromboplastin or activated partial thromboplastin time to determine coagulation status may be useful, as priapism may require surgical intervention if medical treatment fails.

Penile blood gas (PBG) test results allow differentiation between high- and low-flow priapism. Low-flow PBG findings may include a pH of less than 7.0, a PCO2 of greater than 60 mm Hg, and a PO2 of less than 30 mm Hg. Variation depends on the duration of the episode. High-flow PBG findings should reflect normal arterial values.

Color-flow penile Doppler imaging is currently the study of choice to differentiate high-flow from low-flow priapism. In patients with high-flow priapism, ultrasonography can help identify and locate fistulas.

In patients with high-flow priapism, selective penile angiography may be required in order to identify the site of the fistula, or to confirm the location of a fistula identified by ultrasound. The fistula can then be closed by embolization.

Perform chest radiography or computed tomography (CT) scanning if the history is consistent with a malignant or metastatic condition. Perform an electrocardiogram if the patient is older than 55 years, has a history of cardiac disease, or is a possible surgical candidate.