Priapism in the ED: Pearls & Pitfalls

Authors: Bradley End, MD (EM Resident Physician, Ohio State University Wexner Medical Center) and Mark J. Conroy, MD (Assistant Professor, Department of Emergency Medicine & Sports Medicine, Ohio State University Wexner Medical Center, @mjconroy_md) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital) and Stephen Alerhand, MD (@SAlerhand)

Background

While an uncommon presenting complaint, priapism is a urologic emergency requiring fast and effective management by emergency physicians to prevent significant morbidity. Defined as a persistent, painful erection lasting greater than four hours beyond, or in the absence of, sexual stimulation, priapism was first documented as a case by Tripe in 1845 [1]. In the following write-up, we will examine the initial evaluation and management of patients presenting to the emergency department.

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Priapus, the Greek god of gardening, fertility, and lust [2]

Case Presentation

An 18-year-old African-American man with past medical history of asthma and HgbSS sickle cell anemia walks into your emergency department with a chief complaint of groin pain. The patient awoke this morning with an erection that has persisted for 5 hours. He had been too embarrassed to seek help until the pain became unbearable. He complains of 10/10 pain in the shaft of his penis without radiation. He has had associated nausea without emesis and has not noticed any fevers or chills. He denies chest pain, dyspnea, or productive cough. He is not sexually active and denies penile discharge or dysuria. In addition, he cannot recall any recent trauma or injury to his penis, scrotum, or perineum.

Vitals are notable for a HR of 102. Physical exam is notable for tachycardia with a normal rhythm and a tumesced diffusely tender penis without scrotal edema or surrounding erythema. The penis is firm laterally and flaccid along the corpus spongiosum and glans. There is no expressible discharge. Testicles are of a normal consistency and non-tender. No inguinal hernias noted. His pulmonary and cardiovascular exams are unremarkable. His abdomen is soft and non-tender diffusely.

Epidemiology

Incidence estimated at 0.3 to 1.0 per 100,000 males. [1]

Bimodal distribution involving ages 5-10 (typically associated with sickle-cell disease or neoplasm) and 40-50 (idiopathic or caused related to pharmacologic agents). [1, 5]

Lifetime incidence in homozygous sickle-cell disease estimated as high as 42%. [1]

Overview

The goal of your initial evaluation is to distinguish between high-flow (non-ischemic) and low flow (ischemic) priapism. This determination will help guide your therapy and ultimate disposition.

High-flow priapism is extremely rare and most commonly associated with antecedent trauma including blunt trauma, or resulting from needle injury of the cavernosal artery. [1,2] This produces excessive arterial flow to the penis leading to persistent erection.

Low-flow priapism is caused by impaired relaxation and/or paralysis of cavernosal smooth muscle [3]. It is most commonly idiopathic, but may be related to intracavernosal injections for erectile dysfunction (papaverine, prostaglandin E1), erectile dysfunction oral medications (sildenafil, tadalafil), anti-hypertensives (hydralazine, prazosin, calcium channel blockers), or neuroleptic medications (trazodone, chlorpromazine) [4]. This condition is a urological emergency.

In sickle-cell disease, chronic dysregulation of the nitric oxide pathway with decreased NO bioavailability can lead to persistent painful erections. Additional studies suggest that elevated adenosine levels may also contribute to priapism, though this data is limited to rodent studies [6].

Timely treatment of priapism is required to prevent erectile dysfunction. Microscopic damage is noted with erections lasting only 4-6 hours. Structural changes of the cavernosal musculature are observable after 12 hours. 90% of men with priapism lasting 24 hours will have permanent erectile dysfunction, and certain case series have reported that all men with erections lasting >36 hours will have abnormal erectile function [3,6].

Workup

Obtain a thorough history including erection duration, any prior episodes, current medications/illicit drug use, history of sickle cell disease, recent penile/perineal trauma, pain presence/absence and severity [3].

In patients with known sickle cell disease, it is recommended to obtain a hemoglobin level and reticulocyte count [6].

Beyond history, physical examination may be helpful, but imaging studies (Doppler ultrasonography) or cavernosal blood gas is the key to differentiating ischemic versus non-ischemic priapism [1,4].

  Non-ischemic Ischemic
Physical Exam Typically painless, not fully tumescent Painful, fully tumescent with corpus cavernosa rigidity without involvement of corpus spongiosum and glans penis
Cavernosal Blood Gas PO2 > 90 mmHg, PCO2 <40 mmHg, pH ~ 7.40 PO2 <30 mmHg, PCO2 >60 mmHg, pH <7.25
Ultrasonography Blood flow observed (turbulence), compression sign positive, may detect cavernous A/V fistula, pseudoaneurysm or other abnormality Decreased or absent blood flow, compression sign negative

 

Management

Non-ischemic priapism is not a urologic emergency and can be followed up as an outpatient with urology, usually within one week. Aspiration and sympathomimetic agents are not effective and may be harmful [1,3,4,5].

Ischemic priapism, on the other hand, is an emergency and should be handled in a stepwise fashion, per the American Urological Association Guidelines. Immediately administer adequate analgesia and consider a penile nerve block prior to initiating further treatment. In cases of iatrogenic priapism, studies have demonstrated conservative measures (excerise, oral salbutamol), though these are cases unlikely to be seen in the ED [2]. Aspiration of cavernosal blood should be attempted primarily, with needle insertion in the lateral aspect of the penis to avoid urethral/nerve/vascular injury. Aspiration should be continued until bright red blood is returned. [1,3] If there is difficulty with aspiration, cold saline may be injected to decrease viscosity of the cavernosal blood. Aspiration has a reported 30% success rate [1]. If aspiration fails, injection of sympathomimetics should be attempted. Phenylephrine is the prefered agent* secondary to its relatively benign side-effect profile (primarly alpha-adrenergic effects without significant beta-adrenergic effects). This should be diluted to 200mcg-500mcg/mL and can be given in 1 mL aliquots every 5-10 minutes until detumescence is achieved, or the total dose of phenylephrine given is 1 mg. Combined with aspiration/saline irrigation, sympathomimetics achieve detumescence in ~80% of patients, though success rates are decreased in patients with erections lasting greater than 6 hours due to decreased efficacy of sympathomimetics in the highly acidic environment of the cavernosal sinus [1]. If the patient fails both outlined therapies (or presents >48 hours after erection onset), emergent urologic surgical consultation is necessary.

*Ephedrine hydrochloride, epinephrine, or norepinephrine are suitable alternatives if phenylephrine is not available, however these drugs may cause significant cardiovascular side-effects [1]

When present in patients with sickle cell disease, some specialists advocate for exchange-transfusion therapy prior to urologic surgery intervention. To decrease the risk of the ASPEN syndrome*, Erythrocytapheresis with a target Hgb of <10 g/dL is recommended [6]

*Association of Sickle cell disease, Priapism, Exchange transfusion and Neurologic events. Effects range from mild headache to seizures and obtundation requiring respiratory support [6]

Pearls

Ischemic priapism is a time-sensitive diagnosis and urologic emergency, time is tissue and erectile function!

– History and physical exam may help delineate ischemic vs. non-ischemic, but cavernous blood gas is paramoun

– Remember to provide adequate analgesia, either with oral medications or through local anesthesia/penile blocks (https://www.youtube.com/watch?v=3p0qEfISggs)

– Aspiration should be performed laterally to avoid damage to the dorsal neurovascular bundle (https://www.youtube.com/watch?v=KWf5MAobWoM)

– A stepwise approach (aspiration, injection of vasoactive agent, emergent urologic consultation for shunt) is the key to success

Pitfalls

– Not obtaining a cavernous blood gas sample to differentiate between ischemic and non-ischemic priapism

– Aspiration at the dorsum of the penis (avoid the neurovascular bundle!)

– Only one attempt at vasoactive injection (may repeat at 5-10 minute intervals until detumescence is achieved)

References / Further Reading

  1. Kazuyoshi, S. Namiki, M. Clinical Management of Priapism: A Review. Word J Mens Health. 2016 April; 34(1): 1-8.
  2. Habous, M et al. Noninvasive treatments for iatrogenic priapism: Do they really work? A prospective multicenter study. Urol Ann. 2016 Apr-Jun; 8(2): 193-196.
  3. Deveci, S. Priapism (2016). In T.W. O’Leary, M. Hockberger, R. Chen, W. Available from http://www.uptodate.com/contents/priapism
  4. Davis, J. E. Chapter 93: Male Genital Problems. In Tintinalli, J. E. Tintinalli’s Emergency Medicine (8e). Retrieved from http://accessmedicine.mhmedical.com/
  5. Ferri, F. F. In Ferri, F. F. Ferri’s Clinical Advisor (2016). Retrieved from https://www.clincalkey.com/
  6. Field, J. J, Vemulakonda, V. M. DeBaun, M. R. Diagnosis and Management of priapism in sickle cell disease (2016). In T.W. Schrier, S. L. Mahoney, D. H. Tirnauer, J. S. UpToDate. Available from http://www.uptodate.com/contents/diagnosis-and-management-of-sickle-cell-disease
  7. Salonia, A et al. European Association of Urology Guidelines on Priapism. Eur Urol. 2014 Feb;65(2):480-9.
  8. Montague DK et al. American Urological Association Guideline on the Management of Priapism. J Urol. 2003 Oct;170(4):1318-24.

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