Priapism

Background

• Priapism is an urgent medical-urological condition of a prolonged penile erection lasting > 4 hours in absence of sexual stimulation.
• There are main 3 types of priapism:
  • Ischemic (low-flow) priapism is a medical emergency and accounts for ≥ 95% of all priapism cases. It may result in permanent erectile dysfunction if left untreated for ≥ 48 hours from symptom onset.
  • Nonischemic (high-flow or arterial) priapism is a rare, nonemergent condition often associated with history of perineal or penile trauma in past 2-3 weeks.
  • Stuttering priapism consists of intermittent, recurrent, and self-limited episodes of prolonged and painful erections similar to ischemic priapism.
• The reported incidence of priapism is 0.3-1.5 per 100,000 males per year. Pediatric ischemic priapism is extremely rare in children without sickle cell disease. In patients with sickle cell disease, stuttering priapism is reported to occur in up to 42% of adults and about 60% of children and adolescents.
• Priapic episodes are often idiopathic, and causes vary by type of priapism. Ischemic episodes may be caused by medications and recreational substances, hematologic disorders particularly sickle cell disease, infections or toxin exposures, metabolic or neurologic disorders, and malignancy. Nonischemic priapism is most often attributed to blunt trauma to the perineum or penis leading to an arterial fistula.
• Priapism may result in permanent erectile dysfunction, particularly if the episode lasts > 36 hours which is generally associated with irreversible structural and functional damage.

Evaluation

• Take comprehensive history, including medical, sexual, history of trauma , duration of erection, past history of priapism.
• Perform a physical examination of genitalia, perineum, and abdomen.
• Perform the following blood tests in all patients presenting with priapism: complete blood count, white blood cell count with differential, platelet count, and coagulation profile (Strong recommendation). Base additional lab testing on combination of history, exam, and lab findings (Strong recommendation); this may include screening for hemoglobinopathies, malignancy, or drug use.
• Diagnose priapism in the presence of prolonged penile erection lasting > 4 hours in absence of sexual stimulation.
• Classify the type of priapism based on clinical presentation and aspiration with blood gas analysis and/or imaging (Strong recommendation).
  • To establish ischemic priapism, use:
    • history - progressively painful and significantly rigid erection
    • penile blood gas analysis - dark blood with abnormal gas values and metabolic changes
    • penile Doppler ultrasound - absence of significant blood flow in cavernous artery.
  • To establish nonischemic priapism, use:
    • history - painless (or minimally painful) partially rigid erection
    • penile blood gas analysis - bright red blood with normal gas values on aspiration
    • penile Doppler ultrasound - normal to high velocity of blood flow in cavernous arteries and turbulent blood flow at site of fistula.
  • Stuttering priapism is ischemic and characterized by history of recurrent, painful, and typically self-limited erections usually lasting < 3 hours.

Management

• Start management of ischemic priapism immediately, ideally within 4-6 hours of onset, using a step-wise approach (Strong recommendation).
  • Anesthesia options include dorsal nerve, circumferential penile, or subcutaneous local penile shaft block; or oral conscious sedation for pediatric patients.
  • For episodes not associated with intracavernous vasoactive injection, perform penile aspiration until bright red blood is obtained (Strong recommendation).
  • For episodes associated with intracavernous vasoactive injection or if aspiration is insufficient, inject phenylephrine (or other sympathomimetic drug) intracavernously (Strong recommendation). Other sympathomimetic options include ephedrine, epinephrine, norepinephrine, etilephrine (etilefrine, not available in the United States), and metaraminol. Intracavernous sympathomimetic agents are contraindicated in patients with malignant or poorly controlled hypertension and those currently receiving monoamine oxidase inhibitors.
  • Perform surgical intervention only after several failures of aspiration and intracavernous injection of sympathomimetic drugs (Strong recommendation).
    • Consider distal shunt procedures first (Weak recommendation), and if failure occurs might consider proximal shunt procedures (Weak recommendation).
    • Consider insertion of penile prosthesis for priapism lasting > 36 hours after onset, or if all other interventions have failed. Early surgery may help maintain penile size and prevent curvature due to cavernosal fibrosis. Penile implant occasionally indicated in patients with sickle cell disease and severe erectile dysfunction, as other options (such as intracavernous injections or phosphodiesterase type 5 inhibitors) should be avoided due to risk of priapic event.
• Nonischemic priapism is nonemergent, and definitive management should be at the discretion of the treating physician.
  • Consider initial conservative management with site specific perineal compression and ice application, particularly in children (Weak recommendation).
  • Consider androgen deprivation therapy in adults only (Weak recommendation).
  • Perform selective embolization if nonoperative management fails (Strong recommendation). Use clinical judgement to determine appropriate duration of nonoperative management.
    • Perform pudendal arteriography to help reveal a characteristic blush at site of injury to cavernosal artery if embolization is planned (Strong recommendation).
    • Consider using temporary material for initial selective arterial embolization procedure (Weak recommendation). If recurrent nonischemic priapism, consider repeating superselective arterial embolization using either temporary or permanent material (Weak recommendation).
    • Follow-up with clinical exam and color duplex ultrasound to determine if embolization was successful, and if in doubt perform a repeat arteriogram.
  • Consider surgical fistula ligation as final treatment option after failure of embolization (Weak recommendation).
• Primary management goal for stuttering ischemic priapism is resolving acute episode (treated as ischemic episode) and prevention of recurrence.
  • Provide patient education on simple, practical measures for achieving resolution of any future episodes, and advise patients on how to seek medical assistance for prolonged episodes.
  • Manage patients with sickle cell disease using same approach as patients without it but while also providing additional supportive measures such as IV hydration with bicarbonates, oxygen, and blood exchange transfusions (Strong recommendation).
    • consider hydroxyurea to treat sickle cell disease and for prevention of stuttering priapism.
    • Consider penile prosthetic implant in patients with sickle cell disease and severe erectile dysfunction, as other options (such as intracavernous injections or phosphodiesterase type 5 inhibitors) should be avoided due to risk of priapic event.
  • Consider prescribing intracavernous sympathomimetic self-injections for home treatment of acute episodes on a temporary basis until ischemic priapism resolves (Weak recommendation).
• For patients with malignancy-associated priapism, provide supportive care and treatment for underlying cancer. Consider palliative penectomy if other treatment options fail to control penile pain.
• Follow-up after priapic event includes evaluation for penile fibrosis and erectile function and assessment of treatment efficacy if prescribing preventive medication for stuttering priapism.