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Priapism

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Includes 2021 AUA/SMSNA Guidelines on Priapism

  • Guideline search up to February 2021

Definition

  • Priapism: a persistent penile erection that continues > 4 hours beyond, or is unrelated to, sexual stimulation★

Classification (3)

  1. Ischemic
  2. Non-ischemic
  3. Recurrent non-ischemic (stuttering)

Ischemic priapism (veno-occlusive, low-flow)

  • Majority of cases
  • Characterized by little or no cavernous blood flow
  • Associated with (features that distinguish this from non-ischemic priapism)
    1. Pain
    2. Fully rigid and tender corpora cavernosa
    3. Abnormal blood gas (i.e., hypoxic, hypercarbic, acidotic)
  • Requires prompt evaluation and may require emergency management

Non-ischemic priapism (arterial, high-flow)

  • Relatively rare
  • May last hours to weeks and is frequently recurrent
  • Pathogenesis:
    • Likely results from unregulated control of arterial inflow and cavernous smooth muscle tone
    • Usually involves perineal or penile trauma resulting in laceration of the cavernous artery (or one of its branches within the corpora) and unregulated cavernous arterial inflow. The arteriolacunar fistula is typically unilateral.
      • Most common cause is a straddle injury to the crura
        • Other mechanisms of traumatic arterial laceration include coital trauma, kicks to the penis or perineum, pelvic fractures, birth canal trauma to the male newborn, needle lacerations, iatrogenic needle injury, complications of penile diagnostics, vascular erosions complicating metastatic infiltration of the corpora, and after iatrogenic trauma from coldknife urethrotomy, corporoplasty, and penile revascularization procedures
          • Sustained partial erection may develop 24 hours after perineal or penile blunt trauma
          • After either aggressive medical management of ischemic priapism or surgical shunting, priapism may rapidly recur with conversion from ischemic (low-flow) to non-ischemic (high-flow)
    • Other causes include Fabry disease and sickle cell anemia
  • Associated with (features that distinguish this from ischemic priapism)
    1. Lack of pain (beyond pain from potential acute traumatic etiology)
    2. Tumescent but less rigid corpora cavernosa
      • Erection is partial and bendable because there is no restriction of venous outflow,
      • Patients do report additional engorgement with sexual stimulation, with return to partial erection after climax
    3. Normal penile blood gas (features that distinguish this from non-ischemic priapism)
  • Once properly diagnosed, does not require emergent intervention

Recurrent ischemic priapism

  • Definition: Recurrent ischemic episodes, with or without meeting the 4-hour time criteria for priapism
    • Unwanted painful erections occur repeatedly with intervening periods of detumescence
    • The key differentiating factor between the current definition of recurrent ischemic priapism and other recurrent priapism-like conditions is the requirement of confirmed penile ischemia.
      • Priapism-like conditions include sleep-related painful erections, undesired prolonged erections, and recurrent non-ischemic priapism
    • Both acute ischemic priapism and non-ischemic priapism may recur over time
  • Commonly known as "stuttering" priapism
  • Commonly associated with sickle cell disease
    • Priapism in children and adolescents is most commonly related to sickle cell disease
      • The sickle cell genetic mutation is the result of a single amino acid substitution in the beta-globin subunit of hemoglobin S.
      • Clinical features seen in homozygous sickle cell disease: chronic hemolysis, vascular occlusion, tissue ischemia, and end-organ damage.
      • Sickle cell trait can be a predisposing factor to ischemic priapism.
    • Pathogenesis is related to hemolysis and reduced nitric oxide
  • Management focuses on treatment of acute episodes and prevention of future events.

Pathogenesis

Risk factors (8)

  1. Medications (9):
    1. α-blockers (prazosin, terazosin, doxazosin, tamsulosin)
    2. Anti-anxiety agents (hydroxyzine)
    3. Anti-depressants and antipsychotics (trazodone, bupropion, fluoxetine, sertraline, lithium, clozapine, risperidone, olanzapine, chlorpromazine, thioridazine, phenothiazines)
    4. Anti-coagulants (heparin, warfarin)
    5. Antihypertensives (hydralazine, guanethidine, propranolol)
    6. Attention-deficit/hyperactivity disorder agents (methylphenidates (concerta, daytrana, focalin, metadate, methylin, quillivant, ritalin), atomoxetine (strattera))
    7. Recreational drugs (alcohol, cocaine (intranasal and topical), marijuana)
    8. Hormones (gonadotropin-releasing hormone, testosterone)
    9. Vasoactive erectile agents (papaverine, phentolamine, prostaglandin E1, oral phosphodiesterase type 5 (PDE5) inhibitors, combination intracavernous therapy)
      • Most case reports describing priapism after use of a PDE5 inhibitor reveal histories of increased risk of priapism: sickle cell disease, spinal cord injury, use of a PDE5 inhibitor recreationally, use of a PDE5 inhibitor in combination with intracavernosal injections, history of penile trauma, use of psychotropic medications, or use of recreational drugs; risk is even lower for daily dosing PDE5 inhibitor
  2. Genitourinary conditions (straddle injury, coital injury, pelvic trauma, kick to penis or perineum, arteriovenous or arteriocavernous bypass surgery, urinary retention)
  3. Thrombotic diseases/states (thrombophilc states (deficiencies of protein C, S or FxV Leiden), asplenia, erythropoietin use, hemodialysis with heparin use, and cessation of warfarin)
  4. Hematologic diseases (sickle cell disease, thalassemia, hemolytic anemias (congential dyserythropoietic anemia type II, unstable hemoglobinopathies, polycythemia, thrombotic thrombocytopenic purpura, multiple myeloma, chronic myelogenous or lymphocytic leukemias)
    1. In homozygous sickle cell anemia, the most common form of SCD, priapism occurs in 23-89% of males by age 18.[2]
  5. Infectious (toxin-mediated) causes (scorpion sting, spider bite, rabies, malaria)
  6. Metabolic conditions (amyloidosis, Fabry disease, gout)
  7. Cancer (metastatic or regional infiltration) (prostate, urethra, testis, bladder, rectum, lung, kidney)
  8. Neurogenic conditions (syphilis, spinal cord injury, autonomic neuropathy, lumbar disk herniation, spinal stenosis, cerebral vascular accident, brain tumor, spinal anesthesia, cauda equina syndrome)

Molecular basis of ischemic and stuttering priapism

  • Direct result of NO imbalance resulting in aberrant molecular signaling, PDE5 activity downregulation, adenosine overproduction, and reductions in Rho-kinase activity, translating into enhanced corporal smooth muscle relaxation and inhibition of vasoconstriction in the penis
  • Excessive adenosine accumulation in the penis, coupled with increased A(2B)R signaling, contributes to priapism in two independent lines of mutant mice.

Diagnosis and Evaluation

UrologySchool.com Summary

  • Recommended
    • History and Physical Exam
    • Labs (2)
      1. Corporal blood gas
      2. CBC
  • Optional
    • Labs (2)
      • Hemoglobin electrophoresis
      • Screening for psychoactive drugs and urine toxicology
    • Imaging
      • Penile duplex Doppler ultrasonography
        • When the diagnosis of acute ischemic versus non-ischemic priapism is indeterminate

History and Physical Exam

  • In the majority of cases, the differentiation of acute ischemic priapism versus NIP may be made using only the history and physical exam. 
    • In cases where the subtype is indeterminate, additional testing may be warranted.

History

  • Signs and Symptoms
    • Sexual history
      • Duration of erection, presence of pain
      • Baseline erectile function
  • Risk factors
    • Medical history
      • Personal or family history of sickle cell disease, hemoglobinopathies, hypercoagulable states
      • Pelvic, genital, or perineal trauma, especially a perineal straddle injury
      • Previous episodes of priapism and method of treatment
    • Medications that might have precipitated the episode
      • Use of any erectogenic therapies (both prescription and nutritional supplements)
      • Use of recreational drugs

Physical Exam

  • Genitalia
    • The corpora cavernosa are typically affected while the corpus spongiosum and the glans penis are not
    • In ischemic priapism, the corpora cavernosa are often fully rigid and tender
    • In non-ischemic priapism, the corporal cavernosa will be tumescent, partially erect, but not completely rigid. The penis is also unlikely to be tender
  • Abdominal, pelvic, and perineum
    • May reveal evidence of trauma or malignancy.

Laboratory

  • Corporal blood gas by aspiration
    • Should be obtained in the emergency evaluation of priapism★
    • Most common diagnostic methods of distinguishing acute ischemic priapism from NIP when the diagnosis cannot be made by history alone
    • Blood aspirated from the corpus cavernosum in patients with acute ischemic priapism is hypoxic (dark red), while corporal blood in NIP patients is normally oxygenated (bright red)
Source PO2 (mm Hg) PCO2 (mm Hg) pH
Normal arterial blood (room air) >90 <40 7.40
Normal mixed venous blood (room air) 40 50 7.35
Ischemic priapism (first corporal aspirate) <30 >60 <7.25
  • CBC
    • May identify elevated white blood cell counts, potentially identifying cases where priapism is due to underlying malignancy (e.g., leukemia). 
    • Among men with sickle cell disease, acute ischemic priapism is associated with lower hemoglobin and elevated lactate dehydrogenase, bilirubin, aspartate aminotransferase, reticulocyte count, white blood cells, and platelet counts.
    • Platelet and eosinophil counts may also be elevated in men with acute ischemic priapism.
    • While these laboratory values may contribute to the identification of underlying cause, they often will not be used to guide treatment of the acute presentation
  • Hemoglobin electrophoresis
    • May be appropriate in select clinical scenarios and based on underlying clinical suspicion (e.g., patient race)
      • In most cases, most men with SCD have been diagnosed previously. 
        • The yield of identifying men with previously undiagnosed SCD among a cohort of men presenting with priapism is not well established. 
      • Electrophoresis and other sickle cell testing should be reserved for select clinical scenarios.
  • Urine and serum toxicology panels
    • A thorough medication and social history may provide enough information for the examining practitioner to determine the underlying cause of the priapism presentation without collection of these studies.
      • Testing for potential substances may have a high rate of false negativity, particularly with synthetic and otherwise altered versions of common illicit substances
      • patient history alone may provide much of this information without needing to perform additional testing

Imaging

Color Doppler US

  • Should not be incorporated into the acute evaluation and management of priapism in the emergency department by non-urologist specialists★
    • Not the primary way to diagnose priapism
  • May be utilized in less clearly delineated cases to differentiate between acute ischemic priapism and non-ischemic priapism★
  • Findings
    • Acute ischemic priapism
      • Bilateral absence of flow through the cavernosal arteries
      • Peak systolic flows <50 cm/sec
      • Mean velocity <6.5 cm/sec
      • Diastolic reversal (i.e., negative end diastolic velocities)
    • Non-ischemic priapism
      • Peak systolic velocities of >50 cm/sec.
      • In the non-acute setting, may identify anatomical abnormalities, such as a cavernous artery fistula or pseudoaneurysm in patients who already have been diagnosed with non-ischemic priapism. These abnormalities may occur following a straddle injury or direct scrotal trauma and are, therefore, most often found in the perineal portions of the corpora cavernosa.

Pelvic MRI

  • Likely does not have a role in the initial diagnostic and treatment phase of priapism★
  • Can be used to demonstrate:
    1. A well-established arteriolar-sinusoidal fistula
    2. Presence and extent of tissue thrombus
    3. Corporal smooth muscle infarction
    4. Corporal malignancy or metastasis

Penile arteriography

  • Too invasive as a diagnostic procedure to differentiate ischemic from nonischemic priapism

Management

Ischemic priapism

Patient Counselling

  • Natural history of untreated acute ischemic priapism is possible permanent loss of erectile function and corporal fibrosis leading to penile shortening
    • ED is the most significant complication in patients with prolonged acute ischemic priapism.
  • All patients with persistent acute ischemic priapism should be counseled that there is the chance of erectile dysfunction
    • If acute ischemic priapism event >36 hours, likelihood of erectile function recovery is low.
    • In a patient with acute ischemic priapism >36 hours, surgical interventions, such as distal shunting, with or without tunneling, may be required to achieve detumescence; as it is unlikely the acute ischemic event will resolve with ICI therapy of phenylephrine and aspiration.
      • As the duration of the priapism increases, patients may be refractory to first-line treatments, such as ICI of phenylephrine and aspiration, with or without irrigation.

Non-surgical management

  • Conservative therapies (i.e., observation, oral medications, cold compresses, exercise) are not recommended in the management of acute ischemic priapism
    • Minimal corporal blood flow in priapism limits of oral agents
    • Cold compresses should never be used in persons with SCD to avoid provoking vasoconstriction and intravascular sickling
  • First-line: intracavernosal phenylephrine and corporal aspiration, with or without irrigation★
    • Clinicians treating acute ischemic priapism may elect to proceed with alpha adrenergics, or aspiration and saline irrigation, or a combination of both therapies based on their clinical judgment★
      • ICI with phenylephrine should begin as rapidly as possible following diagnosis★
        • These statements are taken near verbatim from AUA guidelines, but are conflicting
        • Intracavernosal treatments should not be delayed due to other systemic therapies (e.g., hydration, exchange transfusion), but may be administered concomitantly in most cases.★
        • Surgical shunting should not be performed until both alpha adrenergics and aspiration and saline irrigation have been attempted
        • Even in cases where preserved erectile function is unlikely, clinicians may elect to perform combined treatments to improve penile pain, if present. 
        • Intracavernosal therapies may be deferred when ED is anticipated, and expedited placement of a penile prosthesis is planned.
      • If priapism >36 hours, proceed with surgical procedures, without prolonged attempts at phenylephrine and aspiration/irrigation
        • The response to phenylephrine decreases with increased duration of priapism
          • Corpus cavernosum specimens from patients with prolonged priapism show no contractions to high-dose phenylephrine.
    • Intracavernosal α-adrenergic injection
      • α-agonists (phenylephrine, etilefrine, ephedrine, epinephrine, norepinephrine, metaraminol) cause cavernous smooth muscle contraction of the cavernous artery and arterioles, and therefore are vasoconstricrsto
        • Phenylephrine
          • α-agonist of choice
            • Use in this context is off-label
          • Relatively selective α1-adrenergic receptor agonist with minimal β-mediated ionotropic and chronotropic cardiac effects
          • Technique★
            • The optimal regimen for phenylephrine dosing, frequency, and method of administration has not been clearly defined
              • Phenylephrine diluted in 1mL of normal saline to a concentration of 100-500 mcg doses (optimally premixed by pharmacy to minimize risks of miscalculation/overdose)
              • Doses administered ≥5 minutes apart
              • Administered intracavernosally (not subcutaneously)
              • Administered laterally (3 or 9 o’clock position) near the base of the penile shaft
              • Small needles may be used (e.g., 27G)
              • May be continued for up to 1 hour
                • If the erection persists despite repeated attempts with injections and aspiration/irrigation > 1 hour, proceed with more definitive therapy (i.e., shunting procedure).
              • In cases where the combination of phenylephrine and aspiration/irrigation are performed, aspiration should precede phenylephrine administration to permit fresh, oxygenated blood to fill the corpora and potentially improve the yield of phenylephrine administration
                • The penis is aspirated between successive injections by tightly pinching the shaft at the penoscrotal junction, just below the site of needle insertion
              • No recommendations can be made about maximum safe dosage.
                • Although there is no upper limit to the number of injections which may be performed, injections should be stopped if blood pressure changes are detected.
                  • Hypertensive stroke has been reported as a complication of cumulative administration of 2 mg [20mL if 100 μg/mL; 10ml if 200 μg/mL]
        • Potential side effects of intracavernous sympathomimetics:
          1. Hypertension (most common)
          2. Reflex bradycardia (most common)
          3. Tachycardia
          4. Irregular cardiac rhythms
          5. Headache
          6. Dizziness
        • Patients receiving intracavernosal injections with phenylephrine should be monitored for blood pressure and heart rate★
          • Blood pressure and heart rate monitoring seems especially prudent in patients with a history of cardiovascular disease, hypertension, prior stroke, and those using medications such as monoamine oxidase inhibitors (MAOIs).
        • Use in patients on Monoamine Oxidate Inhibitors (MAOIs) (e.g. isocarboxazid, phenelzine, selegiline, tranylcypromine)
          • No reports of toxicity when used for priapism in males using MAOI
          • Potentiation of phenylephrine effects by prior administration of MAOI is most significant with use of oral phenylephrine, which is dissimilar from intracavernosal administration.
          • Gradual dose escalation may be reasonable when treating priapism in men using these medications.
      • Corporal aspiration, with or without irrigation
        • Corporal aspiration refers to the intracavernosal placement of a needle followed by withdrawal of corporal blood. Irrigation indicates subsequent instillation of fluid (typically saline) into the corpora.
          • These two procedures are often combined to remove clotted, deoxygenated blood and restore arterial flow and smooth muscle and endothelial function. They may be performed alone or combined with instillations of phenylephrine.
            • So studies have compared aspiration and irrigation with saline to alpha adrenergic injections alone
            • In comparing outcomes data between combination therapy of aspiration, irrigation, and intracavernosal alpha adrenergics to alpha adrenergics alone, results appear to suggest greater resolution rates with combination therapy.
        • Aspiration will immediately soften the erection and relieve pain; aspiration alone may relieve priapism in 36% of cases
        • Aspiration should be repeated until no more dark blood is coming out from the corpora and fresh bright red blood is obtained
        • Technique★
          • Steps for aspiration/irrigation with phenylephrine administration:
            1. Perform a penile block with local numbing medication (if not previously performed).
            2. Place a 16-18 gauge butterfly needle in the 3 or 9 o’clock position (to avoid the dorsal neurovascular bundle) on the penis near the base.
            3. Connect the butterfly needle to a 30-60 cc Luer Lock syringe.
            4. Alternate between aspiration of blood clots and instillation of saline (chilled if available and if the patient does not have sickle cell disease) until some degree of detumescence can be achieved.
            5. Instill phenylephrine.
            6. Allow 3-5 minutes of time to pass.
            7. Repeat steps 4-6 until detumescence is achieved or until the decision has been made to proceed with surgical shunting.
            8. If temporary detumescence is achieved with aspiration followed by a rapid refilling of blood despite multiple attempts of phenylephrine instillation, consideration may be given to placement of a firm penile wrap at the time of aspiration to maintain detumescence.

Surgical management (Shunting)

  • Principle of shunt procedure is to reestablish corporal inflow by relieving venous outflow obstruction; this requires creation of a fistula between the corpora cavernosa and the glans penis, corpora cavernosa and corpus spongiousum, or corpora cavernosa and dorsal or saphenous veins.
  • In patients with a distal corporoglanular shunt should be performed
    • A surgical shunt should not be considered as first-line therapy.
  • Indications (2):
    1. Persistent acute ischemic priapism after intracavernosal phenylephrine and aspiration, with or without irrigation★
    2. Injections of sympathomimetics has resulted in a significant cardiovascular side effect
    3. Malignant or poorly controlled hypertension
    5. Consider for ischemic priapism events ≤72 hours
      • In priapism lasting > 72 hours, consideration should be given to foregoing a shunt
  • Approach: distal vs. proximal
    • Distal (6)
      • Percutaneous (3) (through distal glans towards corpus cavernosum) WET
        1. Winter: large-bore needle or angiocatheter (least effective)
        2. Ebbehoj: straight incision with No. 11 blade
        3. T shunt: No. 10 blade is rotated 90° after insertion
          • After Ebbehoj or T shunt, the glans is sutured closed with absorbable suture. Discharge home if the penis remains flaccid for 15 minutes. If erection returns or persists, a second T shunt is recommended on the opposite side of the meatus.
      • Open (3): ACT
        1. Al -Ghorab: excision of a 5-mm circular cone segment of the distal tunica albuginea
        2. Combined distal shunt and corporal tunneling maneuver
        3. Tunnelling: modification of the Al-Ghorab; after excising the circular core of distal tunica albuginea, a 7/8 Hegar dilator is inserted down each corporal body through the tunica window
          • Addition of tunneling may afford slightly higher rates of successful detumescence
      • The optimal type of distal corporoglanular shunt has not been defined★
        • Use of tunneling is associated with greater degradation of post-procedure erectile function compared to distal shunting alone★
    • Proximal (2)
      • Options (open)
        1. Proximal corpus cavernosum to spongiosum shunt (Quackles); require a trans-scrotal or transperineal approach
        2. Proximal corpus cavernosum to saphenous vein shunt (Grayhack) - a wedge of tunica albuginea is removed and the vein is anastomosed end to side of corpora cavernosa.
        3. Proximal corpus cavernosum to deep dorsal vein shunt (Barry)
    • Distal shunts are preferred over proximal
      • There is inadequate evidence to quantify the benefit of performing a proximal shunt (of any kind) in a patient with persistent acute ischemic priapism after distal shunting.★
        • Proximal shunting represents a historical procedure and has largely been replaced by distal shunts with tunneling procedures★
        • Proximal shunts are technically more difficult to perform, likely no surgeons who have extensive experience★
          • Should not be considered a mandatory procedure for men who have been confirmed to have failed distal shunting★
    • Percutaneous distal shunting is less invasive than open distal shunting and can be performed with local anesthetic in the emergency department.
    • Open shunting procedures, especially those that require passage of dilators into the corpora cavernosa, will require general anesthesia and an operating room
  • Complications of shunting (6):
    1. Penile edema
    2. Hematoma
    3. Infection
    4. Urethral fistula
    5. Penile necrosis
    6. Pulmonary embolism
  • Methods to prevent shunt obstruction and subsequent failure (3):
    1. Avoid compressive penile dressings
    2. Consider anticoagulation
    3. Patient should periodically squeeze and release the distal penis to “milk” the shunt maintaining patency
  • Resolution of acute ischemic priapism
    • Characterized by the penis returning to a flaccid, nonpainful state, with restoration of penile blood flow.
      • Oftentimes, persistent penile edema, ecchymosis, and partial erections occur and mimic unresolved priapism. This often relates to the duration of priapism and may also signify segmental regions of cavernosal ischemia/necrosis.
    • After shunting, follow-up with the patient regarding erectile function and any subsequent ED therapies
  • Priapism refractory to shunting
    • A vascular study (such as a PDUS) or cavernosal blood gas should be performed prior to performing additional interventions (repeat distal or proceeding to proximal shunting). ★
      • Goal is to assess penile hemodynamic characteristics and extent of necrosis/fibrosis to differentiate persistent acute ischemic priapism from reactive hyperemia or conversion to non-ischemic priapism and inform secondary treatment decisions
        • Penile corporal blood gas can help with decision making about proceeding to additional surgical procedures including placement of an immediate penile prosthesis.
        • Penile duplex ultrasound
          • Can be used to
            • Differentiate between acute ischemic and non-ischemic priapism
            • Determine shunt patency by showing restoration of cavernosal arterial inflow in a patient who has undergone a distal shunt
          • Use is limited by
            • Number of specialists who can currently perform the procedure
            • Equipment might not be readily available
      • Further surgical decisions should not be based only on exam
      • Evaluating the status of a patient with refractory priapism is particularly important in the event that a patient is referred from another institution and/or the clinician is seeing a patient who had been previously treated elsewhere and a complete patient history may not be available.

Early implantation (within 2 weeks) of penile prosthesis

  • May be considered in a patient with untreated acute ischemic priapism greater than 36 hours or in those who are refractory to shunting, with or without tunneling. ★
    • Alternatively, these men may be managed with conservative therapies such as pain control and outpatient follow-up and bypass more invasive procedures (e.g., surgical shunting).
    • It is important to note that before considering conservative management or penile prosthesis placement in men with a priapism >36 hours, the timeline should be sufficiently confirmed.
      • Patient histories relating to an exact timeline may often be unreliable, particularly in cases of concomitant substance use, episodes of intermittent detumescence, recurrent priapism (e.g., SCD), or partial (not fully rigid) erections. In these settings, clinical judgment is required to identify the true timeline for onset of ischemia (i.e., onset of severe, persistent penile pain). 
      • If the timeline is in question, clinicians should preferentially attempt to decompress the priapism, particularly in younger men or those with high baseline erectile function.
  • Advantages to prostheses placed in the setting of acute ischemic priapism (5):★
    1. Detumescence
    2. Relief of pain
    3. Preservation of penile length
    4. Return to sexual activity
    5. Overall satisfaction
  • Disadvantages to immediate implantation:
    1. Urologist involved for may lack the experience, comfort level, or materials to render device placement practical and/or possible★
    2. Repetitive bedside irrigation procedures may, in theory, increase the chances for bacterial entry into the corpora that could threaten an implant with infection.
      1. Infection rates < 10%, higher with delayed implantation,★
    3. Distal shunts may have compromised the integrity of the tunica albuginea that would surround an implant, possibly predisposing to erosion.

Recurrent Ischemic Priapism

  • Optimal strategies to prevent subsequent episodes are unknown
  • Options★
    • Idiopathic (7):
      1. Ketoconazole with prednisone
        1. Highest success rate
        2. Adverse effects
          1. Liver toxicity, thus warranting frequent assessment of liver function tests
      2. Pseudoephedrine, an oral α-adrenergic agonist, promotes muscle contraction within the erectile tissue
      3. Phosphodiesterase type 5 inhibitors
      4. Aspirin
      5. Baclofen
      6. Dutasteride
      7. Cyproterone acetate
        1. Anti-androgen
        2. Not available in the United States
    • Associated with sickle cell disease
      1. Same options as idiopathic
      2. Etilefrine
      3. Hydroxyurea
      4. Automated exchange transfusion
    • Drug therapy is typically initiated at bedtime
    • Patients with recurrent ischemic priapism should be informed that hormonal regulators (ketoconazole, cyproterone acetate) may impair fertility and sexual function
      • Adverse effects, due to manipulation of hypothalamic-pituitary-gonadal axis
        • Fatigue
        • Hot flashes
        • Breast tenderness
        • Changes in mood
        • ED
        • Negatively impact sperm parameters
    • Home self-injection of intracavernous α-adrenergic agent
      • Not a preventative strategy; may avert a full-blown episode of ischemic priapism when administered at home for prolonged morning erections

Sickle Cell Disease and other Hematologic Disorders

  • The best intervention is to relieve episodes with prompt intracavernosal phenylephrine and corporal aspiration, with or without irrigation, as in other acute ischemic priapism patients, before proceeding to systemic therapies specific to the underlying disorder★
  • Standard sickle cell assessment and interventions should be considered concurrent with initiation of urologic intervention. Specifically, disease specific systemic care should address:
    • Hydration with IV fluid only if made NPO (maintenance rate) or dehydrated (replace deficit plus maintenance rate)
      • Hyperhydration is not indicated and may predispose to acute chest syndrome.
    • Supplemental oxygenation only if hypoxic.
    • Pain management with oral or parenteral opioids as per usual painful events (remembering that some patients with SCD may be tolerant to analgesia because of those prior experiences).
    • Hematologic status comparison of CBC and reticulocyte count to baseline values
      • Best done in consultation with the patient’s hematologist.
      • Transfusion is not indicated if hemoglobin is near usual value, and over-transfusion may be associated with neurologic events.
      • Acute exchange transfusion is not indicated.
      • If operative shunting procedures are required, consideration should be given to a simple transfusion of packed red blood cells to raise the hemoglobin to 9-10 g/dl prior to general anesthesia
      • Rarely are blood products required before an aspiration and irrigation procedure, the one exception may be with a very low platelet count (<20,000/uL).
    • Presence of other acute sickle cell events: neurologic disorders including acute stroke, acute chest syndrome, biliary colic, renal insufficiency which while not associated with a higher frequency of priapism may present at the same time.
  • Ice packs and other cold compresses should never be used in SCD patients as they may worsen painful events by precipitating intravascular sickling.
  • Most patients with SCD experience recurrent short ischemic priapism events, (lasting <4 hours and commonly referred to as stuttering priapism) but acute episodes and particularly recurrent acute episodes occur commonly enough (both before and after shorter, stuttering events) that education about when to seek urologic attention is a critical part of the patient education in SCD disorders.
  • Drugs that have been tried to prevent subsequent priapism episodes
    • Etilefrine
    • Ephedrine
    • Pseudoephedrine
    • Terbutaline
    • PDE5is (e.g., sildenafil, tadalafil)
    • 5 alpha reductase inhibitors (dutasteride or finaseride)
    • Anti-androgens (cyproterone, bicalutamide, leuprolide, stilboesterol)
    • Ketoconazole/prednisone
    • Hydroxyurea
  • Ongoing chronic (monthly) exchange transfusions do appear to be associated with a reduction in acute and stuttering priapism episodes.
    • Exchange transfusion should not be as the primary treatment in patients with acute ischemic priapism associated with sickle cell disease.
    • For prolonged acute priapism events that cannot be relieved with intracavernosal phenylephrine and corporal aspiration, exchange transfusion can be considered

Prolonged Erection Following Intracavernosal Vasoactive Medication

  • A persistent erection following iatrogenic- or patient self-administration of erectogenic medications into the corpus cavernosum (ICI) represents a distinct pathology when compared to acute ischemic priapism or non-ischemic priapism.
  • Prolonged erections, which are ≤4 hours in duration
    • Much more common and may be managed differently than acute ischemic priapism
    • Occur following ICI pharmacotherapy for ED
  • Duration of a persistent erection requiring intervention is not clearly defined. Generally,
    • Erection lasting
      • <1 hour post injection would not require intervention
      • >4 hours would warrant treatment, regardless of underlying etiology
      • Decision to intervene in the time-period between 1 and 4 hours would depend on several clinical factors:
        • Penile rigidity
          • Mild erection (i.e., not sufficient to penetrate without assistance) would not require treatment, whereas a fully rigid erection might
          • Intermittently rigid erection is considered differently than a fully rigid erection, which has remained persistent since the original injection
        • Specific medication used and dosage
          • Alprostadil alone is likely associated with shorter durations of erections and likely has a lower risk of ischemic priapism compared to combination therapies, which include  papaverine and/or phentolamine
          • Higher dosages are empirically more likely to result in a prolonged erection compared to lower ones
        • Age
        • Baseline erectile function
        • Reliability/capacity
        • Comorbid conditions
        • Pain as an indicator for treatment is not relevant in many scenarios, as the intracavernosal medications themselves are often associated with penile pain
    • In patients presenting with a prolonged erection of ≤4 hours following intracavernosal injection pharmacotherapy for erectile dysfunction, clinicians should administer intracavernosal phenylephrine as the initial treatment option
      • Intracavernosal aspiration and irrigation likely represents too aggressive of a therapy for this specific clinical scenario to be used as a first-line therapy
        • The physiologic rationale for aspiration and irrigation is to remove intracavernosal clots and permit entry of fresh blood in an attempt to restore smooth muscle function and vascular drainage.  As the pathologic state of intracavernosal clotting and ischemia likely is not present with prolonged erections <4 hours, aspiration and irrigation is rarely warranted.
          • Persistent, prolonged erections may be considered for aspiration and irrigation if phenylephrine alone is unsuccessful.
    • Other therapies are commonly used to treat prolonged erection, including ice compresses, laying supine, ejaculation, and oral medications such as pseudoephedrine, in the absence of any clinical data demonstrating efficacy
  • All patients should be instructed at the time of ICI training, or after receiving an in-office erectogenic therapy, that they should return to either the office or emergency department if they experience an erection lasting longer than 4 hours.★
    • If a patient experiences a prolonged erection 1-4 hours after home ICI or following an in-office injection, they may be treated with conservative options (in the case of home ICI) or in-office phenylephrine. 
      • Not appropriate for clinicians who administer in-office erectogenic medications to refer the patient to the emergency department as a matter of routine following an in-office injection, rather, the patient should return to the office for detumescence whenever possible.
      • Conservative treatments include applying ice to the penis, ejaculation, exercise, laying supine, and penile compresses
      • Utilize intracavernosal phenylephrine if conservative management is ineffective in the treatment of a prolonged erection.
    • If the erection persists >4 hours they should be treated according to the ischemic priapism algorithm.

Non-ischemic priapism

  • Cavernous aspiration has only a diagnostic role in nonischemic priapism.
    • Repeated aspirations, injection, and irrigation with intracavernous sympathomimetics have no role in the treatment of nonischemic priapism.
  • First-line: observation
    • Non-ischemic priapism is not an emergency; initial observation is recommended★
    • Spontaneous resolution or response to conservative therapy has been reported in up to 62% of cases
      • No comparative studies of intervention vs. conservative management in non-ischemic priapism
    • Conservative measures include ice applied to the perineum and site-specific compression
    • 4-week period is reasonable, unless the patient is severely bothered by the tumesced penis★
      • After the 4-week mark, the patient’s fistula can be re-evaluated using penile duplex ultrasound; the patient’s sexual function and degree of bother can be further quantified. In cases where the fistula is unchanged and/or where patient bother is significant, intervention may be considered.
    • Consider penile duplex ultrasound for assessment of fistula location and size in a patient with diagnosed non-ischemic priapism
      • Screening for anatomical abnormalities and identification of cavernous artery fistula (turbulent flow may be detected) or pseudoaneurysm location and size
      • Ultrasonography is of particular benefit in a patient with NIP being considered for fistula embolization. T
        • Allows for communication between the urologist and radiologist prior to intervention regarding fistula location, size, and eventual choice of vascular access.
      • Ultrasonography may also potentially help with the follow-up of a patient with NIP opting for observation through tracking of fistula and its size.
  • Second-line: percutaneous fistula embolization
    • Indications
      • Persistent NIP who have failed a period of observation and are bothered by persistent penile tumescence, and who wish to be treated
    • Prior to embolization
      • Fistula should be readily visible on a PDUS.
      • Patients should be informed that embolization carries a risk of erectile dysfunction, recurrence, and failure to correct non-ischemic priapism.
        • Pooled analysis suggest that embolization resulted in penile detumescence in 85% of patients, with 80% of men retaining functional erections
          • Bilateral arterial embolization significantly increased the risk of ED.
    • Embolization should only be attempted by an experienced interventional radiologist.
    • In patients who have failed an initial attempt at embolization, patients should be offered a second attempt at an embolization procedure★
      • Embolization of non-ischemic priapism may require retreatment; a single treatment of embolization carries a recurrence rate of 30%.
      • Second attempt at an embolization procedure likely to be more effective and safer than an attempt at surgical ligaton, given the lack of experience in the latter approach for most urologists and the poor data supporting ligation.
  • Surgery
    • Surgical ligation of the corporo-cavernosal fistula following failed attempts at embolization (or when embolization is not available at the center treating the patient) is an option for patients with non-ischemic priapism
    • The lack of familiarity of most urologists with this surgical approach makes the procedure particularly challenging★
      • Surgical approach is transcorporal

Questions

  1. What is the definition of priapism? What are the subtypes?
  2. What proportion of patients will recover erectile function for priapism reversed within a) 12 hours b) 12-24 hours c) 24-36 hours d) >36 hours
  3. After what duration of priapism is shunting no longer recommended?
  4. List risk factors for priapism.
  5. Which medications are associated with risk of priapism?
  6. What are the initial investigations in a patient with suspected priapism?
  7. What is the expected PO2, PCO2, and pH of normal arterial gas vs. mixed venous gas vs. corporal aspirate from ischemic priapism?
  8. What is the maximum dose of phenylephrine that should be administered?
  9. What are potential adverse effects related to phenylephrine injection?
  10. List and briefly describe the different shunting procedures
  11. What are potential complications of shunting?
  12. What are potential advantages to immediate implantation of prosthesis in the management of priapism?
  13. What medication can be used for prophylaxis in stuttering priapism? What are other options?

Answers

  1. What is the definition of priapism? What are the subtypes?
    • Definition: a full or partial erection that continues > 4 hours beyond sexual stimulation and orgasm or is unrelated to sexual stimulation
    • Subtypes: ischemic, stuttering, non-ischemic
  2. What proportion of patients will recover erectile function for priapism reversed within a) 12 hours b) 12-24 hours c) 24-36 hours d) >36 hours
    1. 100%
    2. ≈80%
    3. ≈45%
    4. 0%
  3. After what duration of priapism is shunting no longer recommended?
    • >72 hours
  4. List risk factors for priapism.
  5. Which medications are associated with risk of priapism?
  6. What are the initial investigations in a patient with suspected priapism?
    • H+P, CBC, coagulation profile, blood gas, +/- urine toxicology screen, +/- sickle cell preparation and electrophoresis
  7. What is the expected PO2, PCO2, and pH of normal arterial gas vs. mixed venous gas vs. corporal aspirate from ischemic priapism?
    • Normal arterial blood gas: PO2 > 90, PCO2 <40, pH 7.4
    • Mixed venous gas: PO2 40, PCO2 50, pH 7.35
    • Ischemic priapism: PO2 < 30, PCO2 >60, pH < 7.25
  8. What is the maximum dose of phenylephrine that should be administered?
    • 2mg
  9. What are potential adverse effects related to phenylephrine injection?
    1. Headache
    2. Dizziness
    3. Hypertension
    4. Reflex bradycardia
    5. Tachycardia
    6. Irregular cardiac rhythms
  10. List and briefly describe the different shunting procedures
    • Distal
      • Percutaneous
        1. Winter
        2. Ebbehoj
        3. T-shunt
      • Open
        1. Al-Ghorab
        2. Corporal snake
        3. Combined T-shunt and Corporal Snake
    • Proximal
      1. Cavernosum-spongiosum
      2. Cavernosum-saphenous/deep dorsal vein
  11. What are potential complications of shunting?
    • Penile edema, hematoma, infection, urethral fistula, penile necrosis, and pulmonary embolism
  12. What are potential advantages to immediate implantation of prosthesis in the management of priapism?
    1. Corporal fibrosis not yet established
    2. Penile length may be preserved
  13. What medications can be used for prophylaxis in stuttering priapism?
    1. Phenylephrine
    2. Oral beta agonist
    3. PDE5 inhibitor
    4. GnRH or antiandrogens
    5. Intracavernosal alpha-agonist

References

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