REBEL Core Cast 81.0 – Priapism

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
  • Impotence
  • Thrombosis + Ischemia (resulting from blood stagnation)

Differential Diagnosis

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

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 https://www.youtube.com/watch?v=lCZq-LEcrjA
• Relief of urinary obstruction

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
  • Pseudoephedrine
    • Dose: 60-120 mg PO X 1
    • No quality evidence supporting use
  • 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
• 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 (add image here)
      • 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

1. Govier FE et al. Oral terbutaline for the treatment of priapism. J Urol 1994;151: 878-9. PMID: 8126815
2. Priyadarshi S. Oral terbutaline in the management of pharmacologically induced prolonged erection. Int J Impot Res. 2004;16:424-426. PMID: 14999218

Post Peer Reviewed By: Salim R. Rezaie, MD (Twitter: @srrezaie)