priapism
Summary
Prolonged (>4 hour) painful penile erection unrelated to sexual stimulation, a urologic emergency that can lead to corporal fibrosis and erectile dysfunction. Most cases are ischemic (low-flow) and require urgent decompression.
Detail
Ischemic (low-flow) priapism is a compartment syndrome of the corpora cavernosa with venous outflow obstruction, hypoxia, acidosis, and pain; classic causes include sickle cell disease (especially in children), leukemia, PDE5 inhibitors (sildenafil), intracavernosal injections (e.g., for ED), trazodone, and alpha-1 antagonists. Non-ischemic (high-flow) priapism follows perineal/penile trauma with arteriocavernous fistula; it is typically painless and not as urgent. Diagnosis is largely clinical, supported by cavernosal blood gas (ischemic: dark, hypoxic, acidotic). Management of ischemic priapism: aspiration of corporal blood, intracavernosal phenylephrine (alpha-1 agonist - vasoconstricts, reduces inflow), and surgical shunt if refractory. In sickle cell, also treat with hydration, analgesia, and exchange transfusion.
Sources
- First Aid for USMLE Step 2 CK
- Sketchy Medical
Reviewed by AnkiBoss editorial — medical student review. Information here is for study reference only and is not medical advice. Spotted an error? Let us know.