Procedure series: Priapism

ED MANAGEMENT OF PRIAPISM

Case

You’re moonlighting at a small community ED overnight. Its 3am and a 35-year-old man with a history of depression on trazodone comes in looking distraught and embarrassed. He tells you that around 11pm he woke up with a painful erection that has not gone away. Knowing it’s the middle of the night and that no urologist is going to come in to see the patient at this hour, you proceed down your priapism management algorithm until you are successful… or not.

What is your priapism algorithm?

Priapism is defined as a prolonged penile erection lasting more than 4 hours in the absence of arousal or stimulation.

Priapism is categorized into low-flow and high-flow.

  • Low-flow (ischemic) is the most common form, tends to be very painful, leads to penile ischemia, and is a urologic emergency. Think of it as a compartments syndrome of the penis.
  • High-flow (non-ischemic) is caused by a traumatic arterial-cavernosal fistulas, usually is painless, and does not require urgent treatment.

If the type is unknown, an ABG can be sent to differentiate:

  • Low-flow
    • pO2 <30; pCO2 >60; pH <7.25
  • High-flow
    • pO2 >90 mmHg; pCO2 <40; pH 7.40 (ie, a normal ABG)

Causes of Low-Flow (Ischemic) Priapism

Priapism table

 

Pathophysiology

Priapism is a result of complex blood flow manipulation in and out of the penis via a and ß receptors. In low-flow priapism, when cavernosal pressure approaches arterial pressure, blood flow is reduced, and ischemia results. If not reversed, this leads to acidosis, thrombosis of cavernosal arteries, fibrosis of corporal tissue, and eventually irreversible impotence that can develop within hours.

Anatomy

Knowing the penile shaft anatomy is important in the anesthesia and management of priapism.

 

Cross section penis

Priapism Management Algorithm

*Proceed until detumescence is achieved

  1. IV narcotics/sedation PRN
  2. Penile regional anesthesia: dorsal nerve block +/- ring block
  3. Terbutaline: 0.5 mg SubQ or 5 mg PO
    1. This step is controversial – the AUA does not suggest routine use and recommends instead to proceed to intracorporal phenylephrine
  4. Intracorporal injection of adrenergic agent
    1. Phenylephrine 0.2 to 0.5 mg Q20 min
      1. Max 3 doses in the ED literature
      2. AUA guidelines recommend q5 minutes up to an hour
  5. Corporal aspiration of 30-60 mL of blood and then observation
  6. Irrigate with saline or diluted a-agonist solution (inject and remove 10-20 mL aliquots) multiple times
  7. Consult urology for possible cavernosum-spongiosum shunt

 

Case Conclusion

You suspect a low-flow priapism induced by trazodone so time is of the essence. You start an IV and give the patient some dilaudid for parenteral pain control. You proceed with a dorsal nerve block and inject dilute phenylephrine directly into the corpus cavernosum. That is unsuccessful. You then begin aspirating blood from the corpora and irrigating with normal saline, which finally leads to detumescence. After wrapping the penis in an Ace bandage, you observe him for 2 hours. The priapism does not recur so he is safely discharged home with urgent urology follow up.

 

Pearls

  • Penile anesthesia is easy and effective
  • Steps 4, 5, and 6 can be done in any order or combined
  • You may need to aspirate a small amount of blood prior to injecting phenylephrine if the intracorporal pressures are very high
  • Phenylephrine generally comes in 10mg/mL vials – make sure you dilute it!

 

Deep Dive

Check out our procedures website: http://www.uscemprocedures.wordpress.com

More content/unlocked content coming soon!

 

  • Core Topics Lecture – Dr. Joseph – Urology in the ED: Priapism

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