Overview of Priapism
Priapism is a prolonged, painful penile erection that occurs when blood in the penis is "trapped," or unable to drain. The stagnant blood causes an erection that can last from hours to days. A painful erection lasting for more than 4 hours indicates priapism. If not treated promptly, scarring and permanent inability to achieve an erection (impotence) can result.
Types of Priapism
Veno-occlusive (low-flow) Priapism
Veno-occlusive (blocked vein) priapism develops when circulation in the penis becomes sluggish due to obstructed veins. This type usually occurs without a known cause in men who are otherwise healthy.
Arterial (high-flow) Priapism
This rare, less painful type of priapism results from an injury to the penis or area between scrotum and anus (perineum) that prevents blood in the penis from circulating normally. It indicates a ruptured artery in the penis. There may be a lapse between the time of injury and onset of priapism.
Incidence and Prevalence of Priapism
Priapism can affect men of any age. Most veno-occlusive priapism in men with sickle cell disease occurs between ages 19–21. The rate of veno-occlusive priapism is higher in men who have malaria, leukemia, and Fabry disease.
Risk Factors for Priapism
Diseases that affect blood circulation may predispose men to developing the condition. Forty-two percent of men with sickle cell disease develop veno-occlusive priapism at least once.
Recreational or "party" drug use (e.g., cocaine, ecstasy, marijuana) is a risk factor. An overdose of injectable medication such as papaverine and phentolamine (Regitine®) for erectile dysfunction is also a risk factor. Men with sickle cell disease, leukemia, malaria, and Fabry disease are predisposed to priapism.
Alcohol consumption, androgenic steroids (used to increase muscle size), anticoagulants (Coumadin, Warfilone), and antihypertensives (Prazosin) increase risk. Prolonged sexual activity is also a risk factor.
Causes of Priapism
Priapism may develop as a result of prolonged sexual activity. Other causes include the following:
- Black widow spider bite
- Carbon monoxide poisoning
- Erectile dysfunction injection therapy (if amount of medication injected exceeds prescribed dose)
- Penile or perineal injury (e.g., perineal trauma against the top tube of a bicycle)
- Prescription antidepressive drugs trazodone (Desyrel) and chlorpromazine (Compazine, Serentil)
- Spinal cord trauma
Signs and Symptoms of Priapism
A painful penile erection that lasts 4 hours or more, and a soft head (glans) with a hard shaft are signs of priapism.
Diagnosis includes a patient history and a physical examination to detect an injury or underlying problem.
In veno-occlusive priapism, angiography may be used to help locate blocked veins. Angiography uses a special dye injected into the bloodstream to enable the physician to see blockages on x-ray.
Doppler sonogram (i.e., digital images of ultrasound echos that detect poor blood flow) may be used to diagnose high- or low-flow priapism.
Treatment for Priapism
There are several forms of treatment. Ice packs are applied to the penis and perineum to reduce swelling. Walking up a flight of stairs is sometimes effective, because mild exercise may divert blood flow to other areas of the body. The underlying injury (i.e., ruptured artery) causing high-flow priapism is treated by tying off the artery (surgical ligation) to restore normal blood flow.
Intracavernous Injection to Treat Priapism
Low-flow priapism is treated with vasoconstrictive medications injected into the chambers in the penis that fill with blood to create an erection (corpora cavernosa) to narrow the veins and cause swelling to subside. Alpha agonists terbutaline (Adrenalin, Alupent) and phenylephrine (Neo-Synephrine) are commonly used.
Puncture to Treat Priapism
After numbing the area, a needle is used to drain the blood from the corpora cavernosa to allow the swelling to subside.
Surgical Shunt to Treat Priapism
For veno-occlusive priapism, a passageway (shunt) may be surgically inserted to divert blood flow and reestablish circulation.
The underlying cause is treated when disease is present (e.g., leukemia, sickle cell disease).
The prognosis is good for both types of priapism when the condition is resolved quickly. When treatment is delayed, penile scarring and permanent impotence can result.