Ep 143 Priapism and Urinary Retention: Nuances in Management

In this month's main episode podcast on Urologic Emergencies -  Priapism and Urinary Retention with Dr. Natalie Wolpert and Dr. Yonah Krakowsky we answer questions such as: for priapism, how much time to do we have to fix it before there’s irreversible tissue damage? How is priapism managed differently depending on the cause? What is the value of a corporal blood gas for managing priapism? What are the indications for cavernosal phenylephrine injections? What are the common medications that cause urinary retention that we often miss leading to needless recurrent urinary retention? Why is a suprapubic catheter in many respects safer than a urethral catheter for managing urinary retention? Which patients are at high risk for complications of post-obstructive diuresis? and many more...



Podcast production, sound design & editing by Anton Helman

Written Summary and blog post by Shaun Mehta and Deb Saswata, edited by Anton Helman July, 2020

Cite this podcast as: Helman, A. Episode 143 Priapism and Urinary Retention: Diagnosis and Management. Emergency Medicine Cases. July, 2020. https://emergencymedicinecases.com/priapism-urinary-retention. Accessed [date]

Go to part 2 of this 2-part podcast on urologic emergencies

Priapism: The Ischemic Fifth Limb

Priapism is defined as an unwanted prolonged erection. Similar to acute brain and heart ischemia, time is tissue for ischemic priapism. Initiate treatment as soon as possible, preferably within 4-6 hours to minimize the risk of impotence that occurs in 100% of patients with untreated ischemic priapism at 48 hours.

Low flow vs. High flow Priapism

Low flow priapism is ischemic and a true urologic emergency - a compartment syndrome of the penis, whereas high flow is non-ischemic. Low flow is far more common, with high flow only making up about 2% of presentations.

Priapism is a clinical diagnosis. On exam, key findings include an erect corpus cavernosa with a flaccid glans. There are a number of ways to differentiate ischemic and non-ischemic priapism based on history and lab findings.



A variety of medications and toxins can cause ischemic priapism, including:



* Intra-cavernosal injections (“triple mix” - papaverine, prostaglandin E1 and phentolamine)

* PDE5 inhibitors (sildenafil, tadalafil)

* Anti-hypertensives (hydralazine, prazosin, calcium channel blockers)

* Neuroleptics (trazodone, chlorpromazine)

* Drugs of abuse: cocaine, marijuana



Get a baseline penile blood gas with the first aspiration of intra-cavernosal blood. Although it may not aid in the diagnosis, serial gases may be useful to monitor response to treatment. An ischemic blood gas will be dark, hypoxemic (pO2 200 mL for at least 2 hours after urethral catheter insertion, or > 3L in 24hrs. This is after the initial volume of urine has come out.

Patients who are at high risk of complications as a result of post-obstructive diuresis include patients with abnormal electrolytes or newly elevated creatinine, volume overload, uremic, or confused. These patients should be observed for at least 4 hours following urethral catheter insertion and if urinary output is  > 200ml/hr, they should be admitted with a consult to internal medicine.

Low risk patients (normal electrolytes/creatinine, euvolemic, clinically well) usually do not require observation after the urethral catheter is inserted and distended bladder is relieved.

Duration of indwelling urethral catheter

Our experts recommend that urethral indwelling catheters remain in the bladder for a  duration of 7-10 days. If the catheter is removed too early (ie. in 2-3 days),