Priapism

Priapism is an erection lasting longer than four hours without sexual stimulation. The duration is not a period for watchful waiting: prolonged corporal congestion can permanently injure erectile tissue. In ischemic, or low-flow, priapism, venous outflow is impaired. Deoxygenated blood becomes trapped inside the corpora cavernosa, pressure rises, and the tissue becomes progressively hypoxic and acidic. Smooth-muscle injury and fibrosis can follow, causing permanent erectile dysfunction. This form is usually painful, with a firm or rigid shaft; the glans may remain less firm than the shaft. Non-ischemic, or high-flow, priapism usually results from uncontrolled arterial inflow, often after perineal trauma. The erection is commonly painless and less rigid because oxygenated blood continues to enter the corpora. High-flow priapism is not an immediate emergency, but it still requires assessment and urologic follow-up. A normal erection resolves. A persistent, painful, rigid erection without sexual stimulation should be treated as ischemic until assessment proves otherwise.