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Priapism
Article Last Updated: Jun 6, 2006
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Colin M Dougherty, MD, Staff Physician, Department of Emergency Medicine, Los Angeles County-University of Southern California Medical Center
Coauthor(s):
Allison J Richard, MD, Instructor of Clinical Emergency Medicine, Keck School of Medicine, University of Southern California; Consulting Staff, Department of Emergency Medicine, LAC-USC Medical Center;
Martin J Carey, MD, MB, BCh, MPH, FACEM, FRCS, Program Director, Assistant Professor, Department of Emergency Medicine, University of Arkansas for Medical Sciences
Editors: Lance W Kreplick, MD, MMM, FAAEM, FACEP, Medical Director of Hyperbaric Medicine, Fawcett Wound Management and Hyperbaric Medicine; Consulting Staff in Occupational Health and Rehabilitation, Company Care Occupational Health Services; President and Chief Executive Officer, QED Medical Solutions, LLC; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Richard Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center; John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center; Robert E O'Connor, MD, MPH, Professor and Chair, Department of Emergency Medicine, University of Virginia Health System
Author and Editor Disclosure
Synonyms and related keywords:
priapus, corpora cavernosa, arterial high-flow priapism, veno-occlusive priapism, painful erection of the penis, sickle cell disease, impotence, papaverine use, phentolamine use, prostaglandin E1 use, citalopram, androstenedione, leukemia, thalassemia, multiple myeloma, tumor infiltration, spinal cord injury, spinal anesthesia, Fabry disease, recent infection with mycoplasma pneumonia, amyloidosis, carbon monoxide poisoning, malaria, black widow spider bites, cocaine abuse, marijuana abuse, ethanol abuse
Background
Priapism is the presence of a persistent, usually painful, erection of the penis unrelated to sexual stimulation or desire. It is a true urologic emergency that may lead to permanent erectile dysfunction and penile necrosis if left untreated. Priapism is frequently idiopathic in etiology but is associated with a number of important medical conditions and pharmacologic agents.
Pathophysiology
Priapism is the result of persistent engorgement of the corpora cavernosa of the penis, originating from a disturbance in the mechanisms that control normal penile detumescence. In most cases, the ventral corpora spongiosum and glans penis remain flaccid.
Two types of priapism are generally described. Arterial high-flow priapism usually is secondary to a rupture of a cavernous artery and unregulated flow into the lacunar spaces. This rare type of priapism is usually not painful and results from penetrating penile trauma or a blunt perineal injury. Low-flow priapism is usually due to full and unremitting corporeal veno-occlusion where venous stasis and deoxygenated blood pools within the cavernous tissue. Prolonged veno-occlusive priapism results in fibrosis of the penis and a loss of the ability to achieve an erection. Significant changes at the cellular level are noted within 24 hours in veno-occlusive priapism, whereas arterial priapism is not associated with fibrotic change.
Frequency
United States
The overall incidence of priapism is 1.5 cases per 100,000 person-years, which increases to 2.9 cases per 100,000 person-years for men older than 40 years. In one study, 38-42% of adult patients with sickle cell disease reported at least one episode of priapism.
Mortality/Morbidity
- Deaths have been reported in patients with sickle cell disease presenting with priapism, but the cause of death usually is not related to the priapism per se but to complications from the underlying disease process.
- Morbidity is related to long-term impotence, primarily with veno-occlusive priapism, when diagnosis and therapy have been delayed.
Race
No racial predilection exists. Sickle cell disease, which predisposes to the development of priapism, occurs more frequently in the African American population.
Sex
Priapism is primarily a disease of males. Priapism of the clitoris has been reported but is extremely rare.
Age
- Priapism has been described at nearly all ages, from infancy through old age. A bimodal distribution between 5 and 10 years in children and 20-50 years in adults is noted.
- Younger groups are more often associated with sickle cell disease, while older groups tend to be secondary to pharmacologic agents.
History
- History of thromboembolic (eg, sickle cell disease) or neoplastic disease
- Drug history, including injectable medications used for erectile dysfunction such as papaverine, phentolamine, and prostaglandin E1; antipsychotic oral medications use (eg, trazodone)
- Recent illicit drug use (Cocaine, ecstasy, and marijuana use have been associated.)
- History of trauma or activities that may result in the formation of an arterial-venous fistula or shunt (eg, bicycle riding)
- Degree of pain may help to differentiate between high and low flow varieties of priapism.
- Arterial high-flow priapism
- Priapism secondary to arterial causes also may be significantly less painful than venous priapism.
- Onset of priapism may be delayed after the acute injury. The delay may be due to vessel spasm initially or to the formation of a clot that is gradually reabsorbed over a period of days.
- Priapism secondary to arterial causes usually is less tumescent when compared with venous priapism.
- Veno-occlusive priapism
- Patients with veno-occlusive priapism present with a painful erection.
- Erection may have been present for hours to days.
Physical
- Presence of priapism should be confirmed by the finding of an erect or semierect penis. The ventral glans and corpus spongiosum are rarely rigid.
- Carefully examine for evidence of trauma or unreported injection sites to the genital region.
- Examine the patient for evidence of an underlying condition that may predispose to priapism.
- Piesis sign - Perineal compression with thumb in young children causes prompt detumescence in high-flow priapism.
Causes
- Medications
- Only rare case reports of selective cyclic guanosine monophosphate (cGMP) inhibitors such as sildenafil have been associated with priapism. In fact, several case reports suggest sildenafil as a means to treat priapism and may be able to prevent full-blown episodes from occurring in patients with sickle cell disease.
- Some patients may use injectable medications to induce an erection. In these patients, excessive use may produce priapism. Examples of agents used to induce an erection include papaverine, phentolamine, and prostaglandin E1.
- Many psychotropic medications such as chlorpromazine, trazodone, quetiapine, and thioridazine have been associated with priapism. The newer agents are not immune to this complication. Priapism has been described with citalopram, a selective serotonin reuptake inhibitor.
- Rebound hypercoagulable states with anticoagulants such as heparin and warfarin have been associated. Hydralazine, metoclopramide, omeprazole, hydroxyzine, prazosin, tamoxifen, and androstenedione for athletic performance enhancement.
- Cocaine, marijuana, and ethanol abuse - Recently, the complication has been described in patients using ecstasy.
- Thromboembolic
- Sickle cell disease and thalassemia
- Leukemia and multiple myeloma
- Trauma (pelvic, genital, or perineal)
- Neoplastic (may be primary or metastatic)
- Neurologic
- Spinal cord injury and anesthesia
- Cauda equina compression syndrome
- Infection
- Recent infection with Mycoplasma pneumoniae (Mechanism is thought to be a hypercoagulable state induced by the infection.)
- Malaria
- Other causes
- Fabry disease (rare association, occasionally noted to be priapism of the high-flow type) and amyloidosis
- Carbon monoxide poisoning, black widow spider bites, and vigorous sexual exercise have been implicated.
Other Problems to be Considered
Peyronie disease
Urethral foreign body
Penile surgical implant
Erection from sexual arousal
Lab Studies
- In patients with no known predisposing factors, a complete blood count (CBC) is appropriate in order to identify the rare case of priapism associated with leukemia.
- Patients with sickle cell disease should have a CBC and a reticulocyte count. If sickle cell status is unknown, a hemoglobin S determination may be useful
- An ABG of the cavernous is useful in differentiating between high and low flow disease. Values similar to venous blood suggest a low-flow etiology. Values similar to arterial blood suggest high-flow priapism.
- Coagulation profile
- Platelet count
- Urinalysis
Imaging Studies
- Color flow penile Doppler imaging is currently the study of choice to differentiate high-flow from low-flow priapism.
- In patients with high-flow priapism, selective penile angiography may be required in order to identify the site of the fistula.
Procedures
- Aspiration/injection of the corpus cavernosum
- First perform a penile nerve block, injecting around the entire base of the penile shaft with 1% lidocaine without epinephrine.
- After anesthesia is ensured, use a 19-gauge needle attached to a large syringe and puncture the corpus cavernosum. This should be performed through the shaft of the penis laterally to avoid the corpus spongiosum and urethra ventrally and the neurovascular bundle dorsally.
- Aspirate 20-30 mL of blood from either the 2-o'clock or 10-o'clock position while milking the shaft. Because multiple communications exist from one corpus to the other, aspiration usually is required only on one side.
- If aspiration or injection is successful in producing detumescence, place an elastic bandage around the shaft of the penis to ensure continued emptying of the corpora and to compress the puncture site.
- Aspiration alone has a success rate of around 30%. If this procedure is not successful, phenylephrine, epinephrine, or methylene blue may be instilled into the corpus cavernosa.
Prehospital Care
Any patient who has an erection for longer than 4 hours, especially if he has a predisposing illness (eg, sickle cell disease) probably should receive therapy for priapism. Most cases, if seen early enough in their course, respond to conservative measures.
- Examples of immediate treatment that can be suggested prior to arrival at the hospital may include the use of ice packs to the perineum and penis or asking the patient to walk up stairs.
- The mechanism for the latter strategy is thought to be an arterial steal phenomenon.
- External perineal compression may also be a useful temporizing measure in the ED or prehospital setting.
- If these measures fail to produce rapid detumescence, patients should not delay transfer to the hospital.
Emergency Department Care
Attempt to treat the underlying etiology whenever possible. Treatment for priapism secondary to sickle cell disease includes hydration, alkalization, analgesia, and oxygenation to prevent further sickling. Hypertransfusion and/or exchange transfusions may be required to increase hemoglobin concentration to higher than 10% and decrease hemoglobin S to less than 30% have a high rate of success but may produce serious neurologic side effects.
- Low-flow (vaso-occlusive) priapism
- Some studies suggest that the use of terbutaline orally, at a dose of 5-10 mg, followed by another 5-10 mg 15 minutes later, if required, produces resolution in about one third of patients. This may be a reasonable treatment option when preparing the infusion. If no resolution occurs within 30 minutes, injection therapy is required.
- Oral pseudoephedrine, 60-120 mg orally has also been suggested as a potential therapy due to its alpha-agonist effect. The exact efficacy of this medication orally is unknown.
- If oral therapy fails, aspiration of the corpus cavernosum and intracavernous injection of alpha-adrenergic agents or methylene blue is the next line of therapy.
- If this procedure is not successful, phenylephrine, epinephrine, or methylene blue may be instilled into the corpus cavernosa.
- If initial aspiration of the corpus cavernosum reveals bright red blood rather than the dark venous blood, consider an arterial cause for priapism and institute the steps noted below.
- High-flow (arterial) priapism
- Observation alone may be sufficient as erectile function is usually unimpaired. Compression therapy may be successful in certain cases, especially children.
- Selective angiography with subsequent embolization of the offending vessel has been shown to be effective with few long-term complications in some studies. Patients who do not respond to more conservative measures may benefit from this approach.
- Surgical ligation of the fistula may be required. However, potential complications of this procedure include long-term impotence.
Consultations
Early consultation with a urologist is recommended, especially when less-invasive measures in the ED fail to resolve priapism or high-flow condition is suspected.
Phenylephrine, an alpha-agonist, is very effective in the management of priapism, especially priapism due to iatrogenic injection. Terbutaline is also effective in some cases. The exact mechanism is not clear.
Drug Category: Alpha-adrenergic agonists
These agents have been used successfully in the treatment of priapism, possibly due to their sympathomimetic vasopressor activity.
| Drug Name | Phenylephrine (Neo-Synephrine) |
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| Description | A strong postsynaptic alpha-receptor stimulant with little beta-adrenergic activity that produces vasoconstriction of arterioles in the body. Increases peripheral venous return. The drug is best administered in a dilute solution; add 10 mg (usually 1.0 mL) of phenylephrine to 499 mL of saline 0.9%, yielding a solution with 20 mcg/mL.
Primary benefit in treatment of priapism is vasoconstrictive properties. |
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| Adult Dose | 100-500 mcg/dose, up to 10 doses; use 10-20 mL of 20 mcg/mL solution via intracavernous injection q5-10min
Alternatively, mix 1000 mcg phenylephrine in 100 mL of isotonic sodium chloride solution (10 mcg/mL) and infuse 10-20 mL at a time; if unable to infuse, inject phenylephrine directly in 200- to 500-mcg aliquots; not to exceed 1500 mcg |
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| Pediatric Dose | Administer as in adults |
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| Contraindications | Documented hypersensitivity; severe hypertension or ventricular tachycardia |
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| Interactions | Bretylium may potentiate action of vasopressors on adrenergic receptors, possibly resulting in arrhythmias; MAOIs may significantly enhance adrenergic effects of phenylephrine, and pressor response may be increased 2- to 3-fold;
Guanethidine may increase pressor response of direct-acting vasopressors, possibly resulting in severe hypertension |
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| Pregnancy | C - Safety for use during pregnancy has not been established.
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| Precautions | Caution in elderly patients, hyperthyroidism, myocardial disease, bradycardia, partial heart block or severe arteriosclerosis; in hypovolemia, use is not a substitute for replacement of blood, fluids and electrolytes, and plasma (these should be restored promptly when loss has occurred) |
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| Drug Name | Pseudoephedrine (Sudafed) |
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| Description | Stimulates vasoconstriction by directly stimulating alpha-adrenergic receptors. |
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| Adult Dose | 60-120 mg PO may be given in cases of priapism of short duration (2-4 h)
Primary benefit in treatment of priapism is vasoconstrictive properties |
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| Pediatric Dose | Not established |
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| Contraindications | Documented hypersensitivity; severe anemia, postural hypertension or hypotension, closed angle glaucoma, head trauma, or cerebral hemorrhage |
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| Interactions | Propranolol, MAO inhibitors and sympathomimetic agents may increase toxicity of pseudoephedrine; methyldopa and reserpine may reduce effects of pseudoephedrine |
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| Pregnancy | C - Safety for use during pregnancy has not been established.
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| Precautions | Caution in cardiovascular disease, diabetes mellitus, prostatic hypertrophy and increased intraocular pressure |
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Drug Category: Beta-adrenergic agonists
Agent has been shown to be effective, but the reason is not yet fully elucidated.
| Drug Name | Terbutaline (Brethaire, Bricanyl) |
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| Description | Selective beta2-adrenergic agonist used successfully in the treatment of priapism. |
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| Adult Dose | 5 mg PO, repeated after 15 min; 0.25-0.5 mg SC |
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| Pediatric Dose | <12 years: Not established
>12 years: Administer as in adults |
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| Contraindications | Documented hypersensitivity; tachycardia resulting from cardiac arrhythmias |
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| Interactions | Concomitant use with beta-blockers may inhibit bronchodilating, cardiac, and vasodilating effects of beta agonists; concomitant administration of MAOIs with beta-sympathomimetics may result in a hypertensive crisis; concurrent administration of oxytocic drugs such as ergonovine with terbutaline may result in severe hypotension |
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| Pregnancy | B - Usually safe but benefits must outweigh the risks.
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| Precautions | Through intracellular shunting, terbutaline may decrease serum potassium levels, which can produce adverse cardiovascular effects; decrease is usually transient and may not require supplementation |
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Drug Category: Guanylate cyclase inhibitors
Have second messenger inhibitory effect, affecting muscle relaxation.
| Drug Name | Methylene blue (Urolene Blue) |
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| Description | Inhibits smooth muscle relaxation. |
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| Adult Dose | 1-2 mg/kg IV slowly over 5 min |
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| Pediatric Dose | Not established |
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| Contraindications | Documented hypersensitivity; renal insufficiency |
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| Interactions | None reported |
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| Pregnancy | C - Safety for use during pregnancy has not been established.
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| Precautions | In G-6-PD deficiency, can cause profound anemia; do not inject into the CNS |
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Further Inpatient Care
- Patients with refractory priapism should be admitted to the hospital under the care of a urologist.
Further Outpatient Care
- Ensure adequate follow-up care with a urologist if therapy in the emergency department is successful.
- Some patients may have recurrent priapism. These patients may have a home supply of terbutaline. Instruct these patients on how to self-administer this medication either as a 5-mg tablet or a 0.25-0.5 mg SC prior to presentation.
Transfer
- If a urologist is not available at the presenting institution, transfer patients with priapism who do not respond to ED maneuvers to an appropriate tertiary care center where a urologist is available.
Complications
- A major complication of priapism is long-term impotence. Warn all patients of this possible complication. The fact that this warning was given should be recorded in the chart and clearly written on the discharge instruction sheet. In general, vaso-occlusive priapism has a higher risk of impotence than high-flow arterial priapism.
Prognosis
- Most patients respond to therapeutic measures.
- In high-flow priapism, patients may require surgical intervention to correct the problem.
- Deaths in patients with priapism are usually related to complications from the underlying problem (eg, leukemia, sickle cell disease).
Patient Education
- Warn patients with a predisposing condition for priapism of the symptoms and signs of the condition. Instruct them to report to the nearest ED should priapism develop.
Medical/Legal Pitfalls
- Intervention for vaso-occlusive erections lasting greater than 4 hours duration should be initiated as soon as possible.
- Failure to warn patients of the long-term incidence of impotence is a major concern.
- Careful monitoring of patients at risk of complications due to the use of vasoactive medications should be instituted. Alpha-agonists may cause significant systemic hypertension.
Special Concerns
- Priapism in females is extremely rare but has been described.
- No single therapy has been shown to be effective. Consider terbutaline in the first instance and consultation with a urologist.
- Congenital neonatal priapism may result from birth trauma or other conditions at birth.
- Stuttering or recurrent priapism may occur in patients with sickle cell trait or disease. Usually self-limiting in nature, over time episodes may lead to erectile dysfunction.
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Priapism excerpt Article Last Updated: Jun 6, 2006
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