Priapism: Finding the "off switch"

Priapism is a sustained erection lasting more than 4 hours, and the emergency is distinguishing ischemic from non-ischemic disease. Ischemic priapism is a painful veno-occlusive compartment problem that threatens tissue viability, while non-ischemic priapism usually preserves flow and can often be worked up outpatient.

Emergency Diagnosis of Priapism

• Four-hour time definition: Priapism is defined as a partial or full erection lasting more than 4 hours, a practical threshold that should trigger urgent ED evaluation rather than watchful waiting.
• Ischemic priapism pattern: Ischemic priapism is typically acutely painful with fully rigid corpora cavernosa, reflecting a veno-occlusive low-flow state that can quickly become a tissue-threatening emergency.
• Non-ischemic priapism pattern: Non-ischemic priapism is usually not acutely painful and causes only partial tumescence, with preserved arterial inflow that makes immediate invasive treatment less urgent.
• Aspirate and Doppler clues: Dark cavernosal blood, venous pH below 7.25, and little to no arterial flow on Doppler point to ischemia; bright red blood and preserved flow point the other way. We get into the bedside distinction in the episode.
• Recurrent ischemic priapism: Stuttering priapism causes recurrent painful erections with periods of detumescence and is classically linked to sickle cell disease, though leukemia and other hematologic disorders also matter.

ED Management and Follow-Up

• Local anesthesia first: Initial treatment is performed under penile local anesthesia without epinephrine, typically using a dorsal penile block or circumferential ring block before decompression.
• Core detumescence strategy: Aspiration, saline irrigation, and intracavernosal phenylephrine are the standard first-line tools for ischemic priapism, aimed at relieving pressure and restoring outflow.
• Phenylephrine as vasoactive agent: Phenylephrine is the preferred alpha-adrenergic agent for intracavernosal injection, given in repeated small doses with close reassessment rather than a single one-and-done attempt.
• Needle approach basics: Corporal aspiration is typically done with a 16-18 gauge needle at the base of the shaft, avoiding the ventral surface where the urethra is at risk. We walk through the setup in the chapter.
• Thirty-six hour cutoff: AUA guidance advises against aspiration, irrigation, and phenylephrine once priapism has persisted beyond 36 hours, a key management boundary that changes the plan.
• Disposition and urology follow-up: After detumescence, patients may need admission for pain control or monitoring, and early urology follow-up within 24 to 48 hours is the usual next step.

References: 

1. Bivalacqua TJ, et al. The Diagnosis and Management of Recurrent Ischemic Priapism, Priapism in Sickle Cell Patients, and Non-Ischemic Priapism: An AUA/SMSNA Guideline. J Urol. 2022;208(1):43-52. PMID: 35536142
2. Roghmann F, et al. Incidence of priapism in emergency departments in the United States. J Urol. 2013;190(4):1275-1280. PMID: 23583536
3. Stormont G, et al. Penile Injection And Aspiration. In: StatPearls. Treasure Island (FL): StatPearls Publishing; July 17, 2022. PMID: 32491628