Definition: Prolonged, pathologic erection of the  penis for > 4 hours in the absence of sexual desire. There will be dorsal penile erection with ventral flaccidity resulting from engorgeent of the dorsal corpora cavernosa.

Pathophysiology

  • Low-flow priapism
    • Decreased venous outflow results in increased cavernosal pressure
    • When cavernosal pressure exceeds arterial pressure, ischemia develops
    • More common than high-flow version
    • Typically accompanied by significant pain due to ischemia (can be considered to be compartment syndrome of the penis)
    • Common causes
      • Pediatric: Sickle cell disease, leukemia
      • Adult: Intercavernosal injection (papaverine, phentolamine, PGE1), Anticoagulation, Pharmaceuticals (SSRIs, sedative-hypnotics, erectile dysfunction medications), Illicit drugs (cocaine, extasy)
  • High-flow priapism
    • Excess arterial inflow resulting in priapism
    • Often painless
    • Common causes
      • Arterial laceration
      • Spinal trauma
  • Complications
    • Penile fibrosis
    • Urinary retention
    • Incompetence
    • Thrombosis + Ischemia (resulting from blood stagnation)

Differential Diagnosis

  • Normal sexual arousal
  • Penile trauma
  • Urethral foreign bodies
  • Spinal cord injury
  • Peyronie’s disease
  • Penile implant

Dorsal Penile Nerve Block

Management

Basics:

  • Low-flow or ischemic priapism is an emergency and prompt resolution is vital in avoiding complications
  • Hydration may decrease sludging of blood if present
  • Analgesia
    • Systemic analgesia may not be effective
    • Consider a dorsal penile block
      • Easily performed both by landmark technique as well as US guided
      • Block will facilitate further management
      • Ultrasound guided block 

  • Relief of urinary obstruction

Aspiration + Irrigation Necessary Equipment (Roberts + Hedges’)

Directed Management

  • Expeditious relief of priapism is centrally important. Ongoing ischemia compromises tissue leading to complications including fibrosis and impotence
  • Non-invasive Management
    • Warm compresses: Vasodilation leading to improved blood flow
    • Terbutaline
      • Mechanism of action: beta-2 agonist. Increases venous outflow
      • Dose
        • Oral: 5-10 mg
        • Subcutaneous: 0.25-0.5 mg
        • May repeat once after 15 minutes if no effect
      • Unproven benefit of treatment (Govier 1994, Priyadarshi 2004)
        • Should not delay definitive intervention
        • Limited adverse effects
        • Can be given while setting up for aspiration and irrigation
    • Exchange transfusion
      • Recommended in past for sickle cell patients with priapism but benefit unknown and potential for harm (ASPEN syndrome)
      • Partial exchange transfusion (lower target hemoglobin) has also been recommended
      • Consult hematology for assistance
  • Intracorporal Injection (www.mskcc.org)

    Invasive Management

    • Intracorporal Injection
      • Injection of alpha-adrenergic receptor agonists may cause cavernous smooth muscle contraction allowing for venous outflow
      • Agents
        • Phenylephrine
          • Dose: 200 – 500 mcg (diluted in 1 ml of NS) intracorporal
          • Can repeat injection q20 minutes up to 3 attempts
          • Preferred due to low risk of CV side effects
        • Epinephrine
          • Dose: 100 mcg (diluted in 1 ml NS) intracorporal
          • CV side effects including HTN and dysrhythmias are potential side effects
      • Technique
        • Prepare skin in typical sterile fashion
        • Insert 25- or 27-gauge needle at either the “10 o’clock” or “2 o’clock” position at the base of the penis
        • Aspirate blood to confirm position
        • Inject solution
        • Bilateral injection not necessary as the copora cavernosa communicate
        • Repeat injection in 30 minutes up to a total of 3 injections
    • Aspiration and Irrigation
      • Usually represents definitive management
      • Prepare skin in typical sterile fashion
      • Aspiration
        • Insert 19-gauge “butterfly” needle into corpus cavernosa at “10 o’clock” or “2 o’clock” position
        • Puncture site may be anywhere along corpus cavernosa (do not puncture glans)
        • Advance needle at 45 degree angle to skin while drawing back on syringe until blood is returned (should be almost immediate)
        • Continue aspirating until either bright red (arterial) blood returns or detumescence is achieved
        • If successful, can consider instillation of vasoactive substance (Phenylephrine 200-500 mcg or Epinephrine 100 mcg as above)
        • Tips
          • Use small syringe (10 ml) as high level negative pressure can stop aspiration
          • Access one corpus cavernosa only as the two bodies communicate
      • Irrigation
        • Should be employed if inadequate blood returns on aspiration or detumescence is not achieved
        • Can be performed with or without vasoactive substance but solution containing vasoactive solution most frequently recommended
        • Vasoactive solution
          • Phenylephrine (preferred): 20 mcg/ml solution (1 mg phenylephrine in 500 ml NS)
          • Epinephrine: 1 mcg/ml solution (1 mg epinephrine in 1000 ml NS)
          • Inject 20-30 ml into the cavernosa, withdraw and discard
          • Repeat until volume completed
    • Complications
      • Hematoma and infection are uncommon when proper precautions are taken
      • Systemic circulation of vasoactive medications
        • Place patient on cardiac monitor and check blood pressure frequently
        • Epinephrine has higher risk for CV complications
    • Successful Detumescence
      • Place compressive elastic bandage (not too tight)
      • Consider 3-day course of oral alpha-adrenergic agent (i.e. pseudophedrine)
      • Urology follow up
  • Consult urology if none of the above techniques are unsuccessful for possible shunt placement

Take Home Points

  • Priapism is compartment syndrome of the penis. Ischemia and infarction can occur with prolonged priapism and rapid treatment and detumescence is critical
  • Provide adequate analgesia early to facilitate necessary interventions. Dorsal block of the penis is the most effective analgesic approach
  • Do not delay aspiration and irrigation if more conservative measures fail as complications (fibrosis, impotence) can occur

Read More

McCollough M, Sharieff GQ: Genitourinary and Renal Tract Disorders; in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2014, (Ch) 174: p 2205-2223.

Davis JE, Silverman MA. Urologic Procedures; in Roberts JR: Roberts and Hedges’ Clinical Procedures in Emergency Medicine, ed 6. 2014, (Ch) 55: p 1113-1154

References

Govier FE et al. Oral terbutaline for the treatment of priapism. J Urol 1994;151: 878-9. PMID: 8126815

Priyadarshi S. Oral terbutaline in the management of pharmacologically induced prolonged erection. Int J Impot Res. 2004;16:424-426. PMID: 14999218