Priapism is a condition resulting in a prolonged and uncontrolled erection. Although the incidence is relatively low, because of its time-dependent and progressive nature, priapism is a situation that both urologists and emergency room practitioners must be familiar with and comfortable managing.

Priapism is a persistent penile erection that continues hours beyond, or is unrelated to, sexual stimulation. Typically, only the corpora cavernosa are affected. For the purposes of the Guideline, the definition of priapism is restricted to erections >4 hours in duration. In contrast, a prolonged erection may be defined as an erection which persists longer than desired but <4 hours. There are 2 general classifications of priapism: acute ischemic priapism and non-ischemic priapism (NIP).

Acute ischemic (venoocclusive, low flow) priapism is a nonsexual, persistent erection characterized by little or no cavernous blood flow and abnormal cavernous blood gases (ie hypoxic, hypercarbic, acidotic). The corpora cavernosa are fully rigid and tender to palpation. Patients typically report pain. A variety of etiological factors may contribute to the failure of the detumescence mechanism in this condition. Acute ischemic priapism is an emergency. As the natural history of untreated acute ischemic priapism includes days to weeks of painful erections followed by permanent loss of erectile function, the condition requires prompt evaluation and may require emergency management.

Resolution of acute ischemic priapism is characterized by the penis returning to a flaccid, nonpainful state, with restoration of penile blood flow. However, oftentimes persistent penile edema, ecchymosis and partial erections occur and mimic unresolved priapism. This often relates to the duration of priapism and may also signify segmental regions of cavernosal ischemia/necrosis.

Given the significant heterogeneity of men presenting with acute ischemic priapism, the current Guideline emphasizes that specific interventions should be individualized based on clinical history and findings. While less invasive, stepwise methods may be appropriate for most situations, others may be best managed using expedited surgical interventions. Decisions must also consider patient objectives, available resources and clinician experience. As such, a single pathway for managing the condition is oversimplified and no longer appropriate.

NIP (arterial, high flow) is a persistent erection that may last hours to weeks and is frequently recurrent. Although the underlying physiology is incompletely understood, it likely results from unregulated control of arterial inflow and cavernous smooth muscle tone. Erections are nearly always nonpainful, and cavernosal blood gas measurements are consistent with arterial blood. In contrast to acute ischemic priapism, the non-ischemic variant is not considered a medical emergency. In the current Guideline, we provide guidance related to observation of NIP, imaging to detect a potential fistula with subsequent embolization.

Although NIP does not require urgent urological intervention, acute ischemic priapism represents a medical emergency and may lead to corporal fibrosis and subsequent erectile dysfunction (ED). Thus, all patients with priapism should be evaluated emergently to identify the subtype of priapism (acute ischemic priapism versus NIP) and those with an acute ischemic event provided early intervention when indicated.

Both acute ischemic priapism and NIP may recur over time. The term recurrent ischemic priapism, commonly known as “stuttering” priapism,” signifies an intermittent, recurrent subtype of ischemic priapism, in which unwanted painful erections occur repeatedly with intervening periods of detumescence. Recurrent ischemic priapism is narrowly defined as being a condition in which a patient experiences recurrent ischemic episodes, with or without meeting the previously cited 4-hour time criteria for priapism. Management of this condition not only requires treatment of acute episodes, but also focuses on future prevention and mitigation of an acute ischemic event necessitating surgical management. In this Guideline, we have summarized the major advances using oral pharmacological and endocrine modulating agents to prevent recurrent ischemic priapism.

A prolonged erection following iatrogenic or patient self-administration of erectogenic medications into the corpus cavernosum represents a distinct pathology when compared to acute ischemic priapism or NIP. As such, the natural history and treatment protocols must be differentiated from protocols for true priapism. Given the distinct nature of these iatrogenic erections, several important factors relating to management strategies remain poorly defined, including duration requiring intervention and what constitutes a persistent erection, the impact of underlying intracavernosal medication selection and the efficacy of conservative treatments.

One factor which may be used to determine whether intervention is appropriate is the extent of penile rigidity. As an example, a mild erection (ie not sufficient to penetrate without assistance) would not require treatment, whereas a fully rigid erection might, depending on other factors. Similarly, an intermittently rigid erection is considered differently than a fully rigid erection, which has remained persistent since the original injection.

Several additions have been included in the Guideline since the publication of the AUA Guideline on Priapism in 2010. The role of various diagnostic modalities, specifically the role of imaging (eg ultrasound, computerized tomography, magnetic resonance imaging) is clarified during the initial diagnosis as well as post-treatment, such as with men exhibiting persistent pain or perceived rigidity post-distal shunting.

The 2021 Guideline on Acute Ischemic Priapism, which was developed by the AUA in collaboration with the Sexual Medicine Society of North America, includes greater detail on the roles of:

1. adjunctive laboratory testing in the diagnosis and determination of the etiology of priapism
2. enhanced data for patient counseling on risks of ED and surgical complications
3. the use of intracavernosal phenylephrine with or without irrigation to manage acute ischemic priapism
4. novel surgical techniques (eg distal shunting with tunneling) in acute ischemic priapism patients
5. early penile prosthesis placement in management of acute ischemic priapism
6. pharmacological agents to prevent recurrent ischemic priapism
7. conservative management of NIP

In 2022, the Guideline was updated to include new sections on the evaluation and treatment of patients with NIP, recurrent ischemic priapism, priapism associated with hematological and oncologic diseases, and priapism following intracavernosal vasoactive medications for management of ED.