A Rare Case of Recurrent Idiopathic Low-flow Priapism that Developed into a High-flow Priapism

Abstract

Priapism, according to the American Urological Association is defined as a persistent penile erection that continues hours beyond sexual stimulation; typically, greater than 4 hours. Although priapism is a rare condition and has an unpredictable course in most presentation, it affects 5.36 per 100,000 male subjects per year [1]. Priapism is a urological emergency and delay in treatment or refractory cases can result in cavernous smooth muscle necrosis, fibrosis and penile shortening [2]. There are 2 categories of priapism-namely low-flow (ischemia, veno-occlusive) and high-flow (non-ischemic, arterial) [3,4]. There is a subset of ischemic priapism known as stuttering priapism which presents with recurrent incidences of ischemic priapism varying in length and is usually self-limiting [4]. Low-flow priapism occurs when an occlusive process inhibits the relaxation of the corpus cavernosum, thus the outflow of blood is impaired. The conditions associated with low-flow/ischemic priapism are as follows: sickle cell disease, vasoactive drugs, neoplastic diseases of the penis, urethra, prostate, bladder, kidney, gastrointestinal tract, leukemia, polycythemia, traumatic injury, hyperlipidemic parenteral nutrition, hemodialysis, heparin treatment, Fabry disease and neurologic conditions [3]. On the other hand, high-flow priapism occurs when there is increased arterial blood flow or pooling of blood. Conditions associated with high-flow priapism include traumatic arterio-cavernous fistula, vasoactive drugs, penile revascularization surgery, and neurologic conditions [3]. The mechanism of penile erection is a multifocal phenomenon that involves the nervous system, molecules (nitric oxide, cGMP, calcium), enzymes, and blood vessels. We present an interesting case of a patient with a history of recurrent priapism who converted from a low-flow priapism to a high-flow priapism, thought to be secondary to an arterio-cavernous fistula. Upon further review of PubMed and NIH database, there has been only few of such cases reported. We discuss the diagnostic process and management of high-flow priapism in this report.