> Table of Contents > Priapism
Priapism
Shenelle Wilson, MD
Kelvin A. Moses, MD, PhD
image BASICS
DESCRIPTION
  • Penile erection that lasts for >4 hours and is unrelated to sexual stimulation or excitement.
  • Classified into ischemic and nonischemic types
  • Ischemic (low-flow) priapism is painful and requires urgent clinical intervention.
  • Stuttering priapism is recurrent episodes of short-lived, self-limiting ischemic priapism over an extended period.
  • Nonischemic (high-flow) priapism is painless, could be related to prior trauma, and does not require urgent treatment.
  • Malignant priapism is a rare condition resulting most commonly from penile metastases from primary bladder, prostatic, rectosigmoid, and renal tumors.
  • System(s) affected: reproductive
Pediatric Considerations
In children, nearly all priapism is caused either by sickle cell anemia or trauma (1).
EPIDEMIOLOGY
Incidence
In the United States, one study estimates 1,868 to 2,960 cases of priapism each year. They also noted an increasing incidence from 1998 to 2006, specifically in those from nonhematologic causes (2):
  • Mean age: 33.7 years. There has been an age shift in recent years toward men in their 40s.
  • Other studies have found the incidence of priapism to double in men aged >40 years (2.9 vs. 1.5/100,000 person-years) (3).
  • Race: 61.1% black, 30% white, 6.3% Hispanic
  • Associations: sickle cell anemia (41.9%), drug abuse (7.9%), sickle cell trait (2.5%)
  • Anatomy and physiology
    • The penis consists of three longitudinally oriented corpora: two dorsolaterally paired corpora cavernosa that are responsible for penile erection and a single ventral corpus spongiosum that surrounds the glans penis and extends distally to form the glans penis
    • In general, the penile artery (which is a branch of the internal pudendal artery that, in turn, is a branch from the internal iliac artery) supplies the penis. It divides into three branches: dorsal artery, bulbar artery (supplies the corpus spongiosum), and cavernosal artery (the main blood supply to the erectile tissue).
    • During an erection, smooth muscle relaxation of the cavernosal arterioles results in high-volume inflow to the sinusoids, resulting in compression of the exiting venules. This leads to significant volume expansion of the corpora cavernosa.
    • During the flaccid resting state, the sympathetic nervous system is predominantly in control. Penile tumescence and erection are driven by the parasympathetic nervous system through the generation of nitric oxide (NO).
    • Smooth muscle relaxation occurs via usage of the phosphodiesterase type 5 (PDE-5A) pathway, which generates cyclic guanosine monophosphate (cGMP).
ETIOLOGY AND PATHOPHYSIOLOGY
  • In ischemic priapism, decreased venous outflow results in increased intracavernosal pressure. This leads to erection, decreased arterial inflow, blood stasis, local hypoxia, and acidosis (a compartment syndrome). Eventually, penile tissue necrosis and fibrosis may occur. The exact mechanism is unknown and may involve trapping of erythrocytes in the veins, draining the erectile bodies.
  • In nonischemic priapism, there is increased arterial flow without decreased venous outflow. There is increased inflow and outflow, which results in a sustained, nonpainful, partially rigid erection.
  • Aberrations in the PDE-5A pathway have been proven in mice to be one mechanism of priapism (4).
  • Ischemic priapism
    • Idiopathic, estimated to about 50% (1)
    • Intracavernosal injections of vasoactive drugs for erectile dysfunction
    • Oral agents for erectile dysfunction
    • Pelvic vascular thrombosis
    • Prolonged sexual activity
    • Sickle cell disease and trait
    • Leukemia from infiltration of the corpora
    • Other blood dyscrasias (G6PD deficiency, thrombophilia)
    • Pelvic hematoma or neoplasia (penis, urethra, bladder, prostate, kidney, rectal)
    • Cerebrospinal tumors
    • Asplenism
    • Fabry disease
    • Tertiary syphilis
    • Total parenteral nutrition, especially 20% lipid infusion (results in hyperviscosity)
    • Bladder calculus
    • Trauma to penis
    • UTIs, especially prostatitis, urethritis, cystitis
    • Several drugs suspected as causing priapism (e.g., chlorpromazine, prazosin, cocaine, trazodone, and some corticosteroids); anticoagulants (heparin and warfarin); phosphodiesterase inhibitors (sildenafil, others); immunosuppressants (tacrolimus); and antihypertensives (hydralazine, propranolol, guanethidine)
    • Intracavernous fat emulsion
    • Hyperosmolar IV contrast
    • Spinal cord injury
    • General or spinal anesthesia
    • Heavy alcohol intake or cocaine use
  • Nonischemic priapism
    • The most common cause is penile or perineal trauma resulting in a fistula between the cavernous artery and the corpora.
    • Acute spinal cord injury
    • Rarely, iatrogenic causes for the management of ischemic priapism can result in nonischemic priapism.
    • Certain urologic surgeries have also resulted in nonischemic priapism.
RISK FACTORS
  • Sickle cell anemia, lifetime risk of ischemic priapism 29-42% (1)
  • Dehydration
GENERAL PREVENTION
  • Avoid dehydration.
  • Avoid excessive sexual stimulation.
  • Avoid causative drugs (see “Etiology and Pathophysiology”) when possible.
  • Avoid genital and pelvic trauma.
COMMONLY ASSOCIATED CONDITIONS
  • Sickle cell anemia or sickle cell trait
  • Drug abuse
  • G6PD deficiency
  • Leukemia
  • Neoplasm
image DIAGNOSIS
PHYSICAL EXAM
  • Ischemic priapism
    • Penis is fully erect, corpora cavernosa are rigid and tender, and corpora spongiosum and glans are flaccid. Usually associated with tenderness and pain
  • Nonischemic priapism
    • Penis is partially erect and the corpora cavernosa are semirigid and nontender, with the glans and corpora spongiosum flaccid. Usually not tender or painful
  • Perineum, abdomen, and lymph node exam also valuable to rule out underlying condition.
  • A complete penile and scrotal exam is necessary. Determine if a penile prosthesis is present.
DIAGNOSTIC TESTS & INTERPRETATION
  • CBC with reticulocyte count to detect leukemia or platelet abnormalities
  • Sickling hemoglobin (Hgb) solubility test and Hgb electrophoresis
  • Coagulation profile
  • Platelet count
  • Urinalysis
  • Urine toxicology if illicit drugs suspected
  • Corporal blood gas (CBG) should be used to distinguish ischemic from nonischemic priapism.
  • A color duplex ultrasound of the penis and perineum may be necessary to differentiate ischemic from nonischemic priapism. In ischemic priapism, there is no blood flow in the cavernosal arteries, whereas in nonischemic patients, there is high blood flow (1); may also see fistulas or pseudoaneurysms suggestive of nonischemic priapism.
  • Penile arteriography can be used to identify the presence and site of fistulas in patients with nonischemic priapism.
Diagnostic Procedures/Other
A physical exam is usually able to distinguish ischemic from nonischemic priapism; however, CBG is the most definitive method.
Test Interpretation
  • Pelvic vascular thrombosis
  • Partial thrombosis of corpora cavernosa of the penis
  • Corpus spongiosum, glans penis: no involvement
  • Arterial priapism will show arteriocavernous fistula.
P.853

image TREATMENT
  • Ischemic priapism requires immediate treatment to preserve future erectile function (a longer delay in treatment means a higher chance of future impotence).
    • Cavernosal aspiration with a large bore needle with irrigation (success rate ˜30%) (1,5)
    • Cavernosal injection of phenylephrine (&agr;-adrenergic sympathomimetic) with monitoring of patient's BP and pulse (success rate ˜65%) (5). Inject q5-10min until detumescence.
    • Continue aspiration, irrigation, and phenylephrine for several hours. If this fails, shunt procedures are considered (first a distal shunt).
  • Nonischemic priapism
    • Initial observation
    • If this fails, arteriography and embolization with absorbable materials (5% rate of impotence vs. 39% with permanent materials) or surgical ligation as a last resort (5)
  • Treat the underlying condition (i.e., sickle cell disease). Do not delay intracavernous treatment.
GENERAL MEASURES
  • Reassure the patient about the outcome, if warranted.
  • Provide continuous caudal or spinal anesthesia if the etiology is neurogenic.
  • Treat any underlying cause.
  • In sickle cell anemia: IV hydration; supplemental oxygen; partial exchange or repeated transfusions to reduce percentage of sickle cells to <50%
  • Relieve the patient's pain.
  • Initiating proper management depends on whether the priapism is ischemic or nonischemic.
MEDICATION
  • Opioids for pain, if needed
  • Intracavernous injection of phenylephrine is recommended by the American Urological Association for ischemic priapism (5).
  • Phenylephrine minimizes risk of cardiovascular side effects that are more common with other sympathomimetics; terbutaline has been studied and may be effective (uncontrolled trials showed a 65% resolution rate) for priapism caused by self-injection of agents to treat erectile dysfunction (5).
  • Ketoconazole 200 mg TID and prednisone 5 mg daily for 2 weeks; then tapering to ketoconazole 200 mg nightly for 6 months has been shown to prevent recurrent ischemic priapism (6).
  • For stuttering priapism, a trial of gonadotropin-releasing hormone (GnRH) agonists or antiandrogens is effective; self-injection of phenylephrine is also effective.
  • PDE-5 inhibitors also have a role in the prevention of priapism in patients suffering from stuttering priapism (7).
ISSUES FOR REFERRAL
A urologist should be consulted in all cases of suspected priapism to ensure the highest likelihood of preserved erectile function.
SURGERY/OTHER PROCEDURES
  • For ischemic priapism, introduction of 18- or 19-gauge needle into corpora cavernosa (best done by urologist if available) at 9 o'clock and 3 o'clock positions with aspiration of 20 to 30 mL of blood from corpus cavernosum. May follow with intracavernous injection of 100 to 500 &mgr;g phenylephrine (mix 0.2 mL [200 &mgr;g]) of 1% phenylephrine in 9.8 mL of normal saline. 1 mL injections given every 3 to 5 min for ˜1 hour before determining if treatment is successful. If this fails, consider shunts.
  • Distal shunts
    • Percutaneous: Ebbehoj, Winter, or T-shunt (8,9,10)
    • Open: Al-Ghorab or corporal snake (11,12)
  • Proximal shunts
    • Open: Quackles or Sacher (13,14)
    • Saphenous vein shunt (15)
    • Deep dorsal vein shunt (16)
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Bed rest until priapism resolves
Patient Monitoring
Close follow-up with a urologist is required after surgical treatments for priapism.
PATIENT EDUCATION
  • Information about long-term outlook, referral for counseling
  • Reduction of vasoactive drug therapy if responsible for priapism, and elimination of offending drugs if causal
PROGNOSIS
  • Even with excellent treatment for a prolonged priapism, detumescence may require several weeks secondary to edema (1).
  • Impotence due to irreversible corporal fibrosis is likely in ischemic priapism and is up to 90% if the priapism lasts >24 hours.
  • Despite early intervention, ischemic priapism is likely to result in impotence in up to 50% of men.
REFERENCES
1. Huang YC, Harraz AM, Shindel AW, et al. Evaluation and management of priapism: 2009 update. Nat Rev Urol. 2009;6(5):262-271.
2. Chrouser KL, Ajiboye OB, Oyetunji TA, et al. Priapism in the United States: the changing role of sickle cell disease. Am J Surg. 2011;201(4):468-474.
3. Eland IA, van der Lei J, Stricker BH, et al. Incidence of priapism in the general population. Urology. 2001;57(5):970-972.
4. Champion HC, Bivalacqua TJ, Takimoto E, et al. Phosphodiesterase-5A dysregulation in penile erectile tissue is a mechanism of priapism. Proc Natl Acad Sci U S A. 2005;102(5):1661-1666.
5. Montague DK, Jarow J, Broderick GA, et al. American Urological Association guideline on the management of priapism. J Urol. 2003;170(4, Pt 1):1318-1324.
6. Hoeh MP, Levine LA. Prevention of recurrent ischemic priapism with ketoconazole: evolution of a treatment protocol and patient outcomes. J Sex Med. 2014;11(1):197-204.
7. Muneer A, Minhas S, Arya M, et al. Stuttering priapism—a review of the therapeutic options. Int J Clin Pract. 2008;62(8):1265-1270.
8. Ebbehoj J. A new operation for priapism. Scand J Plast Reconstr Surg. 1974;8(3):241-242.
9. Winter CC. Cure of idiopathic priapism: new procedure for creating fistula between glans penis and corpora cavernosa. Urology. 1976;8(4):389-391.
10. Brant WO, Garcia MM, Bella AJ, et al. T-shaped shunt and intracavernous tunneling for prolonged ischemic priapism. J Urol. 2009;181(4): 1699-1705.
11. Borrelli M, Mitre AI, Alfer Júnior W, et al. Surgical treatment of priapism using Al-Ghorab's technic [in Portuguese]. Rev Paul Med. 1983;101(1):27-28.
12. Burnett AL, Pierorazio PM. Corporal “snake” maneuver: corporoglanular shunt surgical modification for ischemic priapism. J Sex Med. 2009;6(4):1171-1176.
13. Quackels R. Treatment of a case of priapism by cavernospongious anastomosis [in French]. Acta Urol Belg. 1964;32:5-13.
14. Sacher EC, Sayegh E, Frensilli F, et al. Cavernospongiosum shunt in the treatment of priapism. J Urol. 1972;108(1):97-100.
15. Grayhack JT, McCullough W, O'Conor VJ Jr, et al. Venous bypass to control priapism. Invest Urol. 1964;1:509-513.
16. Barry JM. Priapism: treatment with corpus cavernosum to dorsal vein of penis shunts. J Urol. 1976;116(6):754-756.
Additional Reading
&NA;
  • Burnett AL. Pathophysiology of priapism: dysregulatory erection physiology thesis. J Urol. 2003;170(1):26-34.
  • Pryor J, Akkus E, Alter G, et al. Priapism. J Sex Med. 2004;1(1):116-120.
  • Salonia A, Eardley I, Giuliano F, et al. European Association of Urology guidelines on priapism. Eur Urol. 2014;65(2):480-489.
See Also
&NA;
Anemia, Sickle Cell; Erectile Dysfunction
Codes
&NA;
ICD10
  • N48.30 Priapism, unspecified
  • N48.39 Other priapism
  • N48.31 Priapism due to trauma
Clinical Pearls
&NA;
  • Priapism is a prolonged penile erection that lasts >4 hours and is unrelated to sexual stimulation.
  • In evaluating priapism, the clinician must distinguish ischemic from nonischemic priapism by history and physical exam, as well as blood gas and possibly ultrasound, if needed.
  • Ischemic priapism is an emergent condition that requires immediate urologic evaluation and treatment.
  • The most common causes of ischemic priapism are idiopathic, related to treatments for erectile dysfunction, or related to use of substances (medicinal or recreational).
  • If an underlying medical condition is identified (sickle cell anemia), proper concomitant treatment is necessary to increase the efficacy of treatment.