Priapism

Background

Penis anatomy

• Sustained (> 4h) erection not associated with sexual stimulation
• May lead to erectile dysfunction and penile necrosis
• High rate of sexual dysfunction if present > 24hrs

Types

High-flow (nonischemic)

• Rare
• Associated with trauma or instrumentation
• Usually painless
• Increased arterial flow
• Usually self-resolves and does not require intervention
• Usually does not cause ischemia or sexual dysfunction

Low-flow (ischemic)

• Most common type
• Veno-occlusion causing pooling of deoxygenated blood in cavernous tissue
• Painful
• Urologic emergency
  • May progress to ischemia and necrosis without intervention

Causes

• High-flow
  • Arterio-cavernosal shunt due to groin or straddle injury
  • High spinal injury

• Low-flow
  • Sickle Cell Disease
  • Medications
    • SSRIs/trazodone
    • Antipsychotics
    • Erectile dysfunction medications (e.g. sildenafil)
  • Drugs of abuse
    • Cocaine use
• Leukemia
• Infection
• Latrodectus envenomation (Black widow)
• Idiopathic

Clinical Features

Low-flow

• Pain
• Rigid penile shaft (corpus cavernosum)
• Flaccid penile glans and spongiosum

High-flow

• Painless
• Partially rigid shaft
• Rigid penile glans

Differential Diagnosis

• Peyronie's Disease
• Urethral foreign body
• Penile surgical implant
• Erection from sexual arousal

Non-Traumatic penile diagnoses

• Phimosis
• Balanoposthitis
• Paraphimosis
• Priapism
• STDs

Penile trauma types

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

Evaluation

• CBC
  • Consideration of leukemia or undiagnosed sickle cell disease
• Type and screen
  • May require exchange transfusion in sickle cell disease
• Coagulation profile
• Consider urinalysis/toxicologic screen if unclear etiology
• Cavernosal blood gas may help differentiate high- from low-flow
  • Low flow causes hypoxic, hypercarbic, and acidotic cavernosal blood gases
    • pH < 7.25, pO2 < 30 mmHg, pCO2 > 60 mmHg
• Ultrasound may help distinguish high- from low-flow

Management

(a) Penis rigid and firm in consistency on examination (b) Aspiration from cavernosa using 16G needle showed deoxygenated blood with detumescence.

• Pain control: Morphine and/or penile nerve block
• Running in place or doing squats (or some form of intensive exercise) can potentially achieve detumescence

Low Flow Priapism

Follow a step-wise approach:

• 1. Aspirate 25mL of blood from cavernosum, up to two times
• 2. Irrigate cavernosum with 25mL of cold (10°C) saline
• 3. Medication injections

Aspiration of corpus cavernosum

• Ensure procedure is appropriate
  • Rarely beneficial after 48h
  • Risk of impotence is high even with treatment
• Obtain consent
• Prep the area with chlorhexidine and drape appropriately
• Penile nerve block or local anesthesic at puncture site
• Insert 18 gauge needle into penile shaft at 2 and 10 o'clock positions (or 3 and 9 o'clock positions)
• Aspirate blood (usually 20 - 30 cc on each side)
• May follow with intracavernosal injections (most common is phenylephrine)

α/β-2 Agonist

1. Consider terbutaline
   • Dose: 0.25-0.5mg SQ in deltoids OR 5-10mg PO, may repeat in q20min
2. Phenylephrine
   • Dilute phenylephrine 1ml of 1mg/ml 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 19-Ga needle (after blood aspiration to confirm position)
     • 100-200 mcg every 3-5min (max 1000 mcg) until resolution or 1 hour
   • Ensure patient fully monitored, with BP, HR, pulse oximetry
     • 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 cavernosa
   • Compress injection area to prevent hematoma formation
   • Use with caution in cardiovascular disease
3. Epinephrine
   • In pediatric population, intracavernosal injection of epinephrine instead of phenylephrine has been shown more successful in achieving detumescence

Wrap penis in elastic bandage after detumescence is achieved

Refractory

• Emergent urology consult for possible shunt procedure (can often be done in ED)

High Flow Priapism

• May resolve with observation
• Consult urology for consideration of surgical correction or embolization by interventional radiology

Sickle Cell Disease

• IV hydration
• Pain control
• Supplemental oxygen
• 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