CanadiEM - September 08, 2020 - By Anna Black
..."Priapism is defined as a pathological erection lasting or more hours in the absence of sexual desire or stimulation. In these presentations, it is important to distinguish ischemic (low-flow) priapism from non-ischemic (high-flow), as the former is a medical emergency. While ischemic priapism is more common and associated with a variety of triggers, non-ischemic priapism almost always occurs after penile or perineal trauma, or a needle injury of the cavernosal artery. In both types of priapism, the corpora cavernosa appear engorged but the corpus spongiosum and glans remain flaccid. The corpora cavernosa are fully rigid and painful in ischemic priapism, while they are less painful and not fully rigid in non-ischemic priapism. A doppler ultrasound can aid with the diagnosis by demonstrating decreased blood flow in ischemic priapism and normal or increased blood flow in non-ischemic priapism. A cavernosal blood gas is the most definitive diagnostic test for priapism, with dark, crankcase oil-like blood with a high CO2 content, low O2 content, and low pH indicating ischemic priapism. Ischemic priapism must be treated immediately to preserve erectile function as microscopic tissue damage begins to develop in 4-6 hours, while significant structural damage to smooth muscle occurs after approximately 12 hours. Almost all patients with ischemic priapism lasting >36 hours have erectile dysfunction. Non-ischemic priapism, on the other hand, can generally be managed conservatively as it does not result in tissue damage..."