Priapism

Background

• Prolonged, unwanted erection not associated with sexual stimulation > 4h
  
• May lead to erectile dysfunction and penile necrosis if untreated

Types

High-flow (nonischemic)

• Extremely rare and usually not painful
• AV fistula from trauma (lacerated cavernous artery shunts blood into cavernous bodies)
• Ischemia/impotence does not occur
• Requires less urgent intervention and does not lead to impotence

Low-flow (ischemic)

• Most common type
• Veno-occlusion causing pooling of deoxygenated blood in cavernous tissue
• A urologic emergency

Causes

• Sickle Cell Disease
• Medication induced
• Leukemia
• Infection
• High rate of impotence afterwards if present for > 24hrs
• Cocaine use
• Cervical injury (C5)

Clinical Features

• Erect corpus cavernosum
• Flacid glans and spongiosum

Differential Diagnosis

• Peyronie's Disease
• Urethral foreign body
• Penile surgical implant
• Erection from sexual arousal
• Latrodectus envenomation (Black widow)

Non-Traumatic penile diagnoses

• Phimosis
• Balanoposthitis
• Paraphymosis
• Priapism
• STDs

Penile Trauma

• Penile fracture
• Penile contusion
• Zipper injury to penis
• Traumatic epididymitis
• Penile amputation

Evaluation

• CBC (eval leukemia, sickle cell)
• Type and screen (may need to exchange transfusion)
• Coags
• Urinalysis/tox (etoh, marijuana, cocaine can cause priapism)
• ABG from cavernosa (if history unclear): Hypoxic, hypercapneic, acidotic → low flow
• Ultrasound
  • Can distinguish between high-flow and low-flow

ABG Analysis

• Low-flow priapism is suggested by aspirated blood with a pH of < 7.25, pO2 < 30 mmHg, and pCO2 > 60 mmHg

Treatment

• Pain control: Morphine and/or penile nerve block

Low Flow Priapism

Aspiration of corpus cavernosum

• Written consent prior to invasive procedure
  • Regardless of treatment there is a high risk of impotence
• Rarely beneficial after 48hr
• Penile nerve block or local anesthesia at puncture site
• Aspirate blood from corpus cavernosum (3 or 9 o'clock position of shaft) with 16-19ga needle
• Blood sludging makes aspiration difficult, so to improve flow dynamics use saline irrigation and repeated aspirations
• After removal of 20-30cc of blood, you may inject and aspirate 10-20cc aliquots

α/β-2 Agonist

1. Terbutaline
   • Dose: 0.25-0.5mg SQ in deltoids OR 5-10mg PO, may repeat in q20min
2. Phenylephrine - typical doses are 100-500 mcg per dose
   • Dilute phenylephrine 1mg in 9mL NS for final concentration of 100mcg/mL
     • For 500 mcg/ml, take 0.5 ml of 10mg/ml phenylephrine, and dilute in 9.5 cc NS
   • Inject base of penis with 29-Ga needle (after blood aspiration to confirm position) 0.5-1mL q3-5min until resolution or one hour (max 1500mcg)
     • Ensure patient on the monitor, with BP, HR, pulse ox
     • Reflex bradycardia is expected, so consider dosages relative to toleration of drop from baseline HR
   • Only one side needs to be injected since there exists a vascular channel between the 2 corpora cavernos
   • Compress injection area to prevent hematoma formation
   • Use with caution in cardiovascular disease

Wrap penis in elastic bandage after detumescence is achieved

High Flow Priapism

• Requires urologic consultation for surgical correction or IR guided embolization

Sickle Cell Disease

• IV hydration
• O2
• Transfusion for goal HCT>30% with consultation for partial exchange transfusion (HGB-S<30%)
  • Exchange transfusion is associated with ASPEN syndrome (Association of Sickle cell Priapism, Exchange transfusion & Neurological events)
• Urology consult

Disposition

• Admit if refractory to treatment or need or IR or surgical intervention
• May discharge home if treatment is successful with close follow-up by urology

References

Authors

Daniel Ostermayer, Jordan Swartz, Ross Donaldson, Matthew, Manpreet Singh, Eunice Pae, Kevin Lu, Mark Russell, Christopher Kim, Neil Young, Claire