Priapism: Pathogenesis - Post-cavernosal venous occlusion -> Post-cavernosal venous drainage is mechanically obstructed e.g. sickle cell disease, dialysis etc. - Increased nitric oxide from cavernous nerve plexus and cavernosal sinus endothelia -> Trabecular smooth muscle relaxes, Cavernosal artery smooth muscle relaxes -> Post-cavernosal venules are compressed against tunica albuginea - Impaired detumescence (erection-ending) pathways -> Lack of norepinephrine action on penile SM -> Trabecular smooth muscle and cavernosal artery smooth muscle do not contract -> Ischemic (Low-flow): Inadequate venous function -> Blood pools in corpora cavernosa -> Increased pressure in corpora -> Priapism Prolonged erection lasting more than 4 hours; in absence of sexual stimulation; not relieved by ejaculation #Priapism #Pathophysiology #Urology #Diagnosis
