Priapism Team-based Learning

: Audience: This classic team-based learning (cTBL) module is designed for emergency medicine residents. By the end of this cTBL, the learner will: 1) identify basic penile anatomy, 2) understand pathophysiology behind the varying types of priapism – ischemic, non-ischemic, and stuttering, 3) discuss how to evaluate priapism etiology, 4) recognize how varying priapism types, time course, and mechanism of injury will alter treatment regimen, and 5) know how to administer the appropriate treatment.


Linked objectives, methods and results:
Learners will establish a baseline understanding of priapism and the medical management of the condition through the readiness assessment tests (objective 1 and 2). Learners will then apply this knowledge in a workup of a theoretical patient with a specific type of priapism during the group application exercise (objectives 3 and 4), and then discuss the best treatment for this patient (objective 5). Learners will also consider alternative treatment options when their initial treatment fails (objectives 4 and 5). Learners will confirm their understanding of priapism and various treatment options through a post-test assessment, and have the opportunity to inquire further during the wrap-up.

Recommended pre-reading for instructor:
The instructor should feel comfortable with all answers and explanations within this module. Below are several resources to quickly refresh on the basics of priapism and medical management of the condition. •

Results and tips for successful implementation:
This priapism TBL was tested on a group of 10 learners. As a result of feedback from the session, we eliminated one of the group application exercise (GAE) questions. Of the 10 learners, 6 completed an evaluation form. The overall session was rated an average of 4.33 on a 5-point Likert scale, with 5 being outstanding; 4, excellent; 3, good; 2, fair; 1, poor. Most evaluators (66%) rated the session as highly relevant (4/4 Likert) and 33% of evaluators rated the session as mostly relevant (3/4 Likert).
One week prior to the session, learners should be emailed the learner responsible content (LRC); learners should be reminded two days before the session.

Objectives:
By the end of this cTBL, the learner will: 1. Identify basic penile anatomy. 2. Understand pathophysiology behind the varying types of priapism -ischemic, non-ischemic, and stuttering. 3. Discuss how to evaluate priapism etiology. 4. Recognize how varying priapism types, time course, and mechanism of injury will alter treatment regimen. 5. Know how to administer the appropriate treatment.
You will need approximately one hour to conduct the session. We recommend group sizes of two to four learners. The following timeline was successful for our program: 1. Introduce session (1 minute). 2. Learners complete the iRAT (5-10 minutes; this step can be eliminated if short on time and learners can immediately start with gRAT). 3. Place learners in groups of two to four learners. 4. Groups complete the gRAT (5-10 minutes). 5. Review gRAT answers using powerpoint and instructor RAT answer key (10 minutes). 6. Groups complete the GAE (20 minutes). 7. Instructor reviews the GAE using powerpoint (20 minutes). 3. Typically only the ______________ is/are affected in priapism.

Priapism: individual Readiness Assessment Test (iRAT)
a. Corpora Cavernosa b. Corpora Spongiosum 4. If one were to perform a blood gas on the (answer to #3) in ischemic priapism, the blood gas would be: a. Similar to a normal arterial blood gas b. Hypoxic, hypercarbic, and acidotic c. Similar to a normal mixed venous blood gas 5. If one were to perform a blood gas on the (answer to #3) in nonischemic priapism, the blood gas would be: a. Similar to a normal arterial blood gas b. Hypoxic, hypercarbic, and Acidotic c. Similar to a normal mixed venous blood gas Ultrasound may also be helpful in differentiating between ischemic and nonischemic priapism.
Priapism: group Readiness Assessment Test (gRAT) 1 3. Typically only the ______________ is/are affected in priapism.
a. Corpora Cavernosa b. Corpora Spongiosum 4. If one were to perform a blood gas on the (answer to #3) in ischemic priapism, the blood gas would be: a. Similar to a normal arterial blood gas b. Hypoxic, hypercarbic, and acidotic c. Similar to a normal mixed venous blood gas 5. If one were to perform a blood gas on the (answer to #3) in nonischemic priapism, the blood gas would be: a. Similar to a normal arterial blood gas b. Hypoxic, hypercarbic, and acidotic c. Similar to a normal mixed venous blood gas Ultrasound may also be helpful in differentiating between ischemic and nonischemic priapism.

Priapism: Group Application Exercise (GAE)
A 32-year-old male with a history of sickle cell disease presents to the emergency department with a painful erection lasting for more than four hours.

Low Flow
A urologic emergency characterized by a painful, persistent, fully rigid erection with little to no cavernous blood flow.

Non-Ischemic Arterial High Flow
Persistent erection caused by unregulated cavernous arterial inflow of blood often following trauma.

Stuttering Intermittent
A recurrent form of ischemic priapism, where erections occur repeatedly.

Typically only the ______________ is/are affected in priapism. a. Corpora Cavernosa b. Corpora Spongiosum
Explanation: Only the corpora cavernosa is affected due to the persistent engorgement of the trabecular cavernosal tissue, reducing venous outflow. 1 The corpora spongiosum is not involved due to the relatively smaller volume it contains, and due to insignificant amount of venous outflow obstruction during engorgement. Refer to the image below to visualize the significant engorgement of the corpora cavernosum and venous outflow blockage.
4. If one were to perform a blood gas on the (answer to #3) in ischemic priapism, the blood gas would be: a. Similar to a normal arterial blood gas b. Hypoxic, hypercarbic, and acidotic c. Similar to a normal mixed venous blood gas Explanation: Blood gas analysis on blood drawn from an ischemic priapism would show hypoxia, hypercarbia, and acidemia due to poor O2 supply (low flow state) and reduced venous drainage resulting in decreased concentration of oxygenated blood (hypoxia), increased concentration of pCO2 (hypercarbia and resultant acidemia). 1 See table 1 below.
5. If one were to perform a blood gas on the (answer to #3) in nonischemic priapism, the blood gas would be: a. Similar to a normal arterial blood gas b. Hypoxic, hypercarbic, and acidotic c. Similar to a normal mixed venous blood gas Explanation: Blood gas analysis of a nonischemic priapism would be similar to a normal arterial blood gas because it is the result of an unregulated, high-flow state of engorgement, so the blood would be arterial in nature. 1 Furthermore, these patients tend to have better venous drainage due to the corpora cavernosum not being as engorged when compared to an ischemic priapism. This results in tissue still being well oxygenating and CO2 waste products being removed in a timely manner, preventing the region from becoming acidotic and hypercarbic. Choice C would be the answer for a flaccid penis, and could be used to determine if a priapism has truly resolved. Ultrasound may also be helpful in differentiating between ischemic and nonischemic priapism.
First-line treatment of ischemic priapism for episodes greater than 24hrs: 2 1. Trial above steps, but unlikely to resolve due to extended duration. First-line treatment of ischemic priapism for episodes greater than 72hrs: 2 1. Placement of penile prosthesis. Immediate placement is advantageous due to resolution of priapism, avoidance of shunting complications, prevention of penile shortening, and correction of penile fibrosis and inevitable erectile dysfunction.
Phenylephrine injection procedural steps: 5 1. Insert a 16-or 18-gauge wide bore butterfly into the corpus cavernosum via the glans or lateral aspect of the proximal penile shaft. 2. Aspiration and irrigation occur simultaneously. Aspirate stagnant blood (darker color) and irrigate with sterile normal saline, and continue until new blood (bright red) is drawn. 3. Prepare a sympathomimetic or alpha-adrenergic agonist. Phenylephrine is the preferred agonist, and is to be diluted in normal saline to a concentration of 100-500µg/mL. 4. Inject 100-500µg of phenylephrine directly into the corpus cavernosum every 3-5 minutes. Do not administer more than 1mg/hr. Dosage for pediatric patients or patients with severe cardiovascular disease should be modified accordingly. 5. Monitor the patients' blood pressure and pulse every 15min for 1hr after injection with phenylephrine due to cardiovascular side effects.
One can consider diagnostic testing if the type of priapism is unclear: blood gas testing or ultrasound with Doppler evaluation. Diagnostic assessment of either type of priapism can help to identify main cause to prevent recurrence. It would also be appropriate to initiate treatment for sickle cell disease as long as it doesn't delay priapism treatment.  2 There is not enough data to recommend one shunting technique over another, but erectile dysfunction rates increase with the proximity of shunt. 2

As opposed to the above patient, a patient presents with a penile erection after direct trauma to the pelvis. What type of priapism is this and what is the treatment?
Trauma-induced priapism is most likely nonischemic in nature, but penile blood gas analysis or ultrasound could be used to confirm diagnosis. Nonischemic priapism is a non-emergency and does not require immediate invasive treatment. 1 Patients should have a cold compress on affected penis, and be observed for spontaneous resolution which occurs in up to 62% of reported cases 1 . Aspiration, irrigation, and injection of sympathomimetics or alpha-adrenergic agonists are contraindicated due to high rates of spontaneous resolution and complication profile. 1