Priapism: Too Much of A Good Thing

Andrew Siegel. MD    Blog # 87



A rock-hard erection is a good thing—it is nature in action.  This remarkable change in physical state of our genitals enables us to have sexual intercourse and reproduce.  It is truly an ingenious design and feat of mechanical engineering.  However, when the system fails and an erection does not regress, it is not such a good thing—and in fact can negatively impact our sexual future.  This condition is known as priapism—an unwanted, persistent, painful erection that is not on the basis of sexual stimulation.  The word priapism is derived from the Greek and Roman mythological God of fertility named Priapus.  He is commonly portrayed in classical artwork as having disproportionally large genitals.

Although priapism is an uncommon medical disorder, it is important because of its major potential complications in terms of sexual destiny.  The potential risk when priapism occurs is mechanical damage to the penis. Although priapism is predominantly a male problem, it has been known to involve the female clitoris, the structure that is analogous to the male penis. However, clitoral priapism is an extraordinarily rare occurrence.

Erection mechanics

The penis consists of three cylinders: the solitary corpus spongiosum which contains the urethra (the channel that conducts urine out from the bladder), and the paired erectile cylinders called the corpora cavernosa (erectile bodies), which are anchored internally to the pubic bone and extend to the head of the penis. These erectile cylinders communicate with each other and are enclosed in a fibrous sheath.  The erectile cylinders contain spongy tissue that is endowed with a very rich blood supply. Under the circumstances of erotic or tactile stimulation, the sinuses of the corpora become engorged with blood, resulting in an erection. This seemingly simple process is actually a highly complex event requiring integrated functioning of the brain, nerves, blood vessels, and hormones.


Priapism can occur at any age, ranging from the pediatric to the geriatric population.  When it occurs in children, it is most commonly on the basis of sickle cell disease.  Although many cases of priapism in both adults and children have no clear-cut underlying cause, possibilities include leukemia; use of certain medications; dialysis; neurological infections; herniated discs; spinal cord stenosis; anesthesia; genitourinary cancer; and penile or perineal trauma.   Certain medications—particularly the vasoactive agents injected into the penis as a treatment for erectile dysfunction that has not responded to the commonly used oral medications including Viagra, Levitra and Cialis—are commonly implicated in causing priapism.

Broadly speaking, priapism can be divided into two types, ischemic priapism and non-ischemic priapism.  Ischemia refers to compromised blood flow.  Ischemic priapism is also called veno-occlusive or low-flow priapism and is marked by minimal fresh blood flow within the erectile cylinders the penis—the blood content is old, clotted blood.  It is similar to other compartment syndromes in the body in which there is high-pressure in a closed space with metabolic changes and tissue damage. Ischemic priapism is painful because of the lack of oxygenated (fresh) blood flow to the genital tissues as well as the increased pressure within the erectile cylinders from the erection. Ischemic priapism can ultimately cause tissue necrosis (cellular death of the erectile tissue) and fibrosis (scarring), damaging the erectile tissue such that erectile dysfunction will result.   Generally, if an episode of ischemic priapism persists for more than 4 hours, functional damage to the erectile tissue of the penis will occur.

Non-ischemic priapism is usually on the basis of trauma to the penis or the perineum, the anatomical section of the body located between the scrotum and the anal area. A typical scenario for non-ischemic priapism is a straddle injury resulting from the perineum striking a blunt object such as the top tube of a bicycle or a fence. Non-ischemic priapism is generally not painful.  As a result of the trauma to the blood vessels, an abnormal connection occurs between the artery to the erectile cylinders and the spongy tissue within the erectile cylinders.  This abnormal connection promotes increased blood flow and unregulated blood filling of the erectile cylinders. Non-ischemic priapism is also called arterial or high-flow priapism.

One important diagnostic study is putting a needle into the erectile cylinder of the penis and aspirating (drawing out) blood and submitting it for blood gas testing. In ischemic priapism, the blood is usually dark and sludgy and very low in oxygen content as opposed to patients with non-ischemic priapism who have bright red blood that is well oxygenated. Color duplex ultrasound is another diagnostic method for distinguishing between ischemic and non-ischemic priapism.

Ischemic priapism is treated by decompressing the erectile cylinders to counteract the ischemia and manage the pain.  Initial treatment is evacuating blood from the erectile cylinders and irrigating them to try to release the clotted blood, along with injection of a vasoconstrictor agent (medication that constricts blood vessels), while monitoring blood pressure and cardiac rhythm, since these vasoconstrictors can elevate blood pressure and pulse.  If the ischemic priapism has occurred over an extended duration, it is unlikely to resolve with such local treatment and surgical shunting will likely be necessary.  A surgical shunt is a means of trying to facilitate blood drainage from the erectile cylinders to another anatomical structure.

Management of non-ischemic priapism initially is simply observation. If it fails to resolve, the next step is selective arterial embolization (blocking the abnormal connection by injecting a clotting substance into the injured blood vessel), a procedure done in interventional radiology.

Bottom Line:  As the television commercials state, if you have an erection that lasts more than four hours, call your doctor.  An erection that is prolonged to this duration is truly a medical emergency and could be your last if you do not get help… pronto!

Andrew Siegel, M.D.

Author of Promiscuous Eating: Understanding and Ending Our Self-Destructive Relationship with Food:

Available on Amazon in paperback or Kindle edition

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