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<30-40), acidotic (pH <7.25, pCO2 >60) and glucopenic. Management of priapism: stepwise approach * Dorsal nerve block: retract the penis caudally and insert a small gauge (25-27G) needle on either side of the midline at 10 and 2 o’clock, inject lidocaine (without epinephrine); you should feel a pop when you pass through Buck’s fascia to know you’re in the correct space Dorsal nerve block video here * Corporal aspiration (getting blood out of the penis): insert a 19G butterfly needle into the lateral corpora at the 10 and 2 o’clock positions; aspirate 10-20 mL of blood (while the patient is squeezing the penis proximally) and send a blood gas; avoid the urethra (ventrally) and neurovascular bundle (dorsally); this can be repeated on the other side if priapism persists; a patient’s respons...