Priapism

Aka: Priapism

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II. Definitions

  1. Priapism
    1. Prolonged Erection lasts longer than 4 hours
    2. Priapism lasts longer than 6 hours (associated with increased risk of permanent dysfunction)

III. Pathophysiology

  1. Penile corpora cavernosa engorged
  2. Ventral corpora spongiosum and glans are not engorged (flaccid)

IV. Precautions

  1. Priapism is a medical emergency
    1. Results in a permanent difficulty in obtaining future Erection if left untreated
  2. Priapism in children can be due to underlying blood disorder
    1. Consider Leukemia (may require leukopheresis)
    2. See Priapism in Sickle Cell Anemia

V. Causes

  1. Ascending Nerve Impulses from Urethral lesion
  2. Descending Nerve Impulses from cerebral lesion
  3. Direct stimulation
    1. Spinal cord lesion
    2. Nervi erigentes
  4. Local injury
    1. Thrombosis
    2. Hemorrhage
    3. Neoplasm
    4. Inflammation
  5. Medications: Systemic
    1. Phosphodiesterase Type 5 Inhibitors (e.g. Sildenafil or Viagra)
      1. Can occur, but surprisingly a less common cause of Priapism
    2. Psychiatric medications
      1. Citalopram (Celexa)
      2. Trazodone
      3. Chlorpromazine
      4. Quetiapine
      5. Thioridazine
    3. Anticoagulants with rebound Hypercoagulable state
      1. Warfarin (Coumadin)
      2. Heparin
    4. Miscellaneous Medications
      1. Hydralazine
      2. Omeprazole
      3. Metoclopramide
      4. Prazosin
      5. Hydroxyzine
  6. Medications: Intracorporal Injections
    1. Intracorporal Alprostadil (Caverject)
    2. Papaverine
    3. Phentolamine
    4. Prostaglandin E1
  7. Illicit Drugs and Alcohol
    1. Cocaine
    2. Ecstasy
    3. Marijuana
    4. Alcohol Abuse
  8. Hematologic Disorders
    1. Leukemia
    2. Multiple Myeloma
    3. Sickle Cell Anemia (33% risk of Priapism)
      1. See Priapism in Sickle Cell Anemia
      2. Responsible for two thirds of ischemic Priapism (low flow Priapism) cases

VI. Types

  1. Ischemic Priapism or low-flow priapsim (most cases)
    1. Corporeal venous Occlusion
    2. Results in in Venous Stasis and corporeal ischemia
    3. Left untreated, complicated by penile fibrosis and permanent inability to achieve Erection
  2. Traumatic Priapism or arterial high-flow Priapism (rare)
    1. Cavernous artery rupture
    2. Results from penile or perineal Trauma (e.g. straddle injury)

VII. Symptoms

  1. Prolonged, persistant penile Erection
  2. Ocurs without sexual desire
  3. Painful Erection (except in Traumatic, high flow Priapism)

VIII. Signs

  1. General
    1. Stigmata of underlying systemic cause
  2. Penis
    1. Observe for signs of Trauma to suggest arterial high-flow Priapism
    2. Observe for injection sites
    3. Confirm rigid corpus cavernosum
    4. Expect flaccid glans and corpus spongiosum
  3. Piesis sign (for Priapism in young children - high flow Priapism)
    1. Compressing perineum with thumb will result in near immediate detumescence of the penis

IX. Labs

  1. Arterial Blood Gas from corpora aspiration (if refractory to non-invasive measures)
    1. Critical to distinguish high flow from low flow Priapism
    2. Low flow (ischemic, most cases) states have low pH (acidotic)
    3. High flow (uncommon) states have normal pH
  2. Optional labs and as dictated by suspected by underlying cause
    1. Complete Blood Count (CBC) with Platelets
    2. Urinalysis
    3. Coagulation tests (PT, PTT)

X. Imaging

  1. Penis Doppler Ultrasound
    1. Indicated if type of Priapism unclear
    2. Can distinguish high-flow (Traumatic) from low-flow (ischemic) Priapism

XI. Management: Ischemic Priapism (venous Occlusion, low-flow Priapism)

  1. Urology emergent Consultation
    1. Surgical shunt placement may be required in severe cases refractory to measures listed below
  2. Systemic medications (variable efficacy, but non-invasive)
    1. Beta Agonist (30% success rate)
      1. Terbutaline 5-10 mg orally followed in 15 minutes by an additional 5-10 mg orally
    2. Alpha Agonist
      1. Pseudophedrine 60-120 mg orally for 1 dose
  3. Aspiration of corpora
    1. Anesthesia
      1. Conscious Sedation or
      2. Dorsal Penile Nerve Block
        1. Inject 1% Lidocaine without Epinephrine at the base of the penis at 11:00 and 1:00
    2. Needle: 19-21 gauge butterfly needle or similar on a control syringe
    3. Insert needle at 9:00 to 10:00 or 2:00 to 3:00
      1. Aspirate either corpus cavernosum (both sides communicate)
      2. Compress shaft while aspirating
    4. Protocol
      1. Withdraw 10 to 20 ml blood at a time
        1. May require hundreds of ml of blood aspirated total
        2. Continued large volumes of aspirated blood may suggest high flow state (check ABG as below)
      2. Send first aspiration sample for Arterial Blood Gas
        1. Low pH confirms low-flow (ischemic)
        2. If normal pH suggests high flow state and stop aspiration (no endpoint will be reached)
      3. Continue to withdraw until
        1. Detumescence or
        2. No further blood may be aspirated or
        3. High flow state identified (stop aspiration as aspiration is otherwise limitless)
    5. Adjunctive measures: Phenylephrine
      1. Inject Phenylephrine 0.1 mg of 0.1 mg/ml solution (see dilution below) at a time
      2. May inject up to a total of 0.5 mg (up to 1 mg in some guidelines)
      3. See Phenylephrine as below
    6. Complications
      1. Penile scars
      2. Erectile Dysfunction
    7. Endpoint: Detumescence
    8. Efficacy: 30% success rate
  4. Phenylephrine 1% (10 mg/ml)
    1. Indications
      1. Typically performed in combination with corpora aspiration as above
    2. Preparation
      1. Dilute 1 ml (10 mg) in 9 ml NS for a final concentration 1 mg/ml
    3. Protocol
      1. Inject intracorporal 0.1 mg (1 ml) every 5-10 minutes
      2. Cummulative maximum dose (0.5 mg or 5 ml, up to 1 mg in some guidelines)
      3. Repeat Phenylephrine until detumescence (or maximum dose reached)
    4. Monitoring
      1. Monitor Blood Pressure and Pulse every 15 min
      2. Monitor for minimum of one hour
  5. Surgical Shunt (performed by urology)
    1. Conscious Sedation
    2. Urologist makes a stab incision through glans and into corpora, and then turns scalpel within stab incision
    3. Allows for corporal decompression via glans, which has its own vascular supply (unimpeded by Erection)
  6. Sickle Cell Anemia
    1. May require transfusion

XII. Management: High flow Priapism

  1. Precautions
    1. Confirm high flow state by history, exam, Ultrasound or Arterial Blood Gas from corporal aspiration
    2. If unclear state, start with evaluation and treatment of low flow state as above
      1. Obtain corporal aspiration ABG and if pH normal treat as high flow state
  2. Further management
    1. High flow states are not emergency conditions as contrasted with low flow states (ischemic)
    2. Embolization may be needed

XIII. Complications

  1. Permanent Erectile Dysfunction
    1. Higher risk for Erection lasting longer than 6 hours (and esp. >12 hours)

XIV. References

  1. Herman and Arhancet (2020) Crit Dec Emerg Med 34(10): 17-21

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