Penile blood gas determination for the evaluation of priapism

Priapism is a penile erection that is sustained beyond or is unrelated to sexual stimulation. Depending on the etiology of the priapism, there may be low blood flow to the tissue, causing ischemic priapism, or high blood flow, called nonischemic priapism. Ischemic priapism is assessed in part by corporal blood gas analysis and should be treated emergently to preserve tissue health and function. Ischemic priapism is a common morbidity associated with sickle cell disease (SCD).

A 16-year-old male individual presented at the emergency department with priapism. His medical history was clinically significant for SCD and prior episodes of priapism. He was not on medications to manage SCD at that time. Corporal blood aspiration was performed to attempt detumescence, and an aliquot of that blood was sent to the laboratory for blood gas analysis.

The blood submitted for analysis was deep red, and blood gas results revealed acidosis, hypercarbia, and hypoxemia. These results were consistent with ischemic priapism and prompted more aggressive treatment and patient monitoring.

This case illustrates the role of blood gas analysis in the evaluation of priapism. Laboratorians should be aware of this rare sample type that may present with extreme values.