Priapism is a prolonged erection of the penis. The unwanted, persistent erection isn't caused by sexual stimulation or arousal, and it's usually painful. Priapism is an uncommon condition that needs immediate medical attention. Prompt treatment for priapism is usually needed to prevent tissue damage that results in the inability of the penis to become or stay erect with sexual arousal (erectile dysfunction). Priapism is most common in boys between ages 5 and 10 years old and in men from ages 20 to 50 years.

Complications of Priapism

Ischemic priapism can cause serious complications. The blood trapped in the penis is deprived of its oxygen supply and becomes toxic to tissues. When the erection lasts for more than four hours, the oxygen-poor blood can begin to damage or destroy tissues in the penis. As a result, untreated priapism may cause:

• Erectile dysfunction, the inability of the penis to become or stay erect with sexual arousal
• Disfiguring of the penis

Causes of Priapism

An erection normally occurs in response to physical or psychological stimulation. This stimulation causes certain blood vessels to relax and expand, increasing blood flow to spongy tissues in the penis. Blood vessels that control the flow of blood out of the penis contract, trapping blood. Consequently, the blood-filled penis becomes erect. After stimulation ends, the blood flows out, and the penis returns to its nonrigid (flaccid) state. Priapism occurs when some part of this system — the blood, blood vessels or nerves — changes normal blood flow. Subsequently, an unwanted erection persists. Factors that can contribute to priapism include the following.

Blood disorders

Blood-related diseases may contribute to priapism — usually ischemic priapism, a persistent erection caused by blood not being able to flow from the penis. These disorders include:

• Sickle cell anemia
• Leukemia

Sickle cell anemia, one of the most common causes of priapism, is an inherited disorder characterized by abnormally shaped red blood cells. These abnormally shaped cells can block the flow of blood. Sickle cell anemia is the most common cause of priapism in boys.

Prescription medications

Priapism, usually ischemic priapism, is a known side effect of a number of drugs. The following drugs can sometimes cause priapism:

• Oral medications used to manage erectile dysfunction, such as sildenafil (Viagra) and vardenafil (Levitra)
• Drugs injected directly into the penis to treat erectile dysfunction, such as papaverine
• Antidepressants, such as fluoxetine (Prozac) and bupropion (Wellbutrin)
• Drugs used to treat psychotic disorders, such as risperidone (Risperdal) and olanzapine (Zyprexa)
• Anti-anxiety medications, such as diazepam (Valium)
• Blood thinners, such as warfarin (Coumadin) and heparin

Illicit or recreational drug use

Some illicit drugs or the abuse of drugs can cause priapism, particularly ischemic priapism. Possible causes include:

• Recreational use of erectile dysfunction drugs
• Excessive alcohol consumption
• Use of cocaine, marijuana or ecstasy

Injury

A common cause of nonischemic priapism — a persistent erection caused by excessive blood flow into the penis — is trauma or injury to your genitals, pelvis or the perineum, the region between the base of the penis and the anus.

Other factors

Other causes of priapism include:

• Spinal cord injury
• Diseases of the nervous system, such as multiple sclerosis
• Metabolic diseases, such as diabetes
• Blood clots
• Poisonous venom, such as venom from scorpions or black widow spiders

In some cases, doctors are unable to identify the specific cause for priapism.

Signs & Symptoms of Priapism

Priapism causes abnormally persistent erections. Priapism symptoms vary somewhat depending on the type of priapism.

Ischemic priapism

Ischemic, or low-flow, priapism is the result of blood not being able to exit the penis. Signs and symptoms include:

• Unwanted, erection lasting more than four hours
• Rigid penile shaft, but usually soft tip of penis (glans)
• Erection not related to sexual stimulation or persistent after stimulation
• Usually painful or tender penis

Nonischemic priapism

Nonischemic, or high-flow, priapism occurs when too much blood flows into the penis. Signs and symptoms include:

• Unwanted erection lasting at least four hours
• Erect but not rigid penile shaft
• Erection not related to sexual stimulation or persistent after stimulation
• Usually painless

Stuttering priapism

Stuttering, or recurring, priapism is a form of ischemic priapism that occurs off and on. A stuttering erection is usually painful but generally lasts fewer than three hours.

Diagnosis of Priapism

If you have an erection lasting more than four hours, you need emergency care. The emergency room doctor will determine first whether you have ischemic priapism or nonischemic priapism. This is necessary because the treatment for each is different, and treatment for ischemic priapism needs to be done as soon as possible. Your answers to questions, a physical examination and a blood test are usually enough to determine what type of priapism you have. You will undergo additional tests to determine the underlying cause of priapism, which may need to be treated, usually in a nonemergency setting.

Medical history and exam

In order to determine what type of priapism you have, your doctor will likely ask the following questions:

• How long has the erection lasted?
• Is the erection painful?
• What prescription drugs do you take?
• Have you used any illicit drugs?
• Have you used erectile dysfunction drugs recreationally?
• How much alcohol have you consumed recently?
• Do you have sickle cell anemia or another blood disorder?
• Have you had previous episodes of persistent erections, and were you treated for the condition?
• Have you recently experienced an injury or trauma near your genitals?

Your doctor will also examine your genitals, abdomen, groin and perineum. He or she may be able to determine what type of priapism you have based on the rigidity and sensitivity of the penis. This exam may also reveal signs of injury or tumors that could be causing priapism. An injury, for example, would suggest that nonischemic priapism is more likely.

Diagnostic tests

Diagnostic tests may be necessary to determine what type of priapism you have. Additional tests may identify the cause of priapism. In an emergency room setting, your treatment may begin before all test results are received if the doctor is confident about what kind of priapism you have. Diagnostic tests include:

• Blood gas measurement. In this test, a tiny needle is inserted into your penis to remove a sample of blood. If the blood is dark — deprived of oxygen — the condition is most likely ischemic priapism. If it's bright red, the priapism is most likely nonischemic. A laboratory test measuring the amounts of certain gases in the blood can confirm the type of priapism.
• Blood tests. Your blood can be tested to measure the amount of red blood cells and platelets present. Results may provide evidence of diseases, such as sickle cell anemia, other blood disorders or certain cancers.
• Ultrasound. You may undergo a color duplex ultrasonography, which uses sound waves to create an image of internal organs. This test can be used to evaluate blood flow within your penis that would suggest ischemic or nonischemic priapism. The exam may also reveal an injury, tumor or abnormality that may be an underlying cause.
• Toxicology test. Your doctor may order a toxicology test to screen for illicit or prescription drugs that may be the cause of priapism. This may be done with blood or urine samples.

Treatments of Priapism

Ischemic priapism

Ischemic priapism — the result of blood not being able to exit the penis — is an emergency situation that requires immediate treatment. This treatment usually begins with a combination of draining blood from the penis and using medications.

• Aspiration. After your penis is numbed with local anesthetic, excess blood is drained from it, using a small needle and syringe. As part of this procedure, the penile veins also may be flushed with a saline solution. This treatment relieves pain, clears the tissues of oxygen-poor blood and may stop the erection. This treatment may be repeated frequently over several hours until the erection ends.
• Medication. Injection of a drug called an alpha-adrenergic sympathomimetic, such as phenylephrine, may be injected into the spongy tissue of the penis. This drug constricts blood vessels transporting blood into the penis, thereby limiting blood flow in. This action allows blood vessels transporting blood out of the penis to open up, allowing increased blood flow out. This treatment may be repeated frequently over several hours if necessary. There is some risk of side effects, particularly if you have high blood pressure or heart disease.
• Surgery. If other treatments aren't successful, a surgeon may implant a shunt, a device that reroutes blood flow so that it moves through your penis normally.
• Additional treatments. If you have sickle cell anemia, you may receive additional treatments that are used to treat disease-related episodes, such as supplemental oxygen or an intravenous solution to keep you well hydrated.

Nonischemic priapism

Nonischemic priapism often goes away with no treatment. Because there isn't a risk of damage to the penis, your doctor may suggest a watch-and-wait approach. Putting ice and pressure on the perineum — the region between the base of the penis and the anus — may help end the erection. Surgery may be necessary in some cases to insert material that temporarily blocks blood flow to the penis. The body eventually absorbs the material. Surgery may also be necessary to repair arteries or tissue damage resulting from an injury.

Prevention of Priapism

Depending on the probable cause of the priapism, steps to prevent priapism may include:

• Treating the disease that may have caused priapism
• Changing medications if a prescription medication was the probable cause
• Avoiding triggers, such as alcohol or illicit drugs
• Self-injection of phenylephrine to stop prolonged erections
• Hormone treatment — only for adult men
• Prescription muscle relaxant, such as baclofen (Lioresal)

When to seek Medical Advice

• Go to the emergency room if you have an erection lasting more than four hours.
• If you experience a painful, persistent erection that resolves on its own in less than four hours, see your doctor, because you may need treatment to prevent further episodes.