Priapism is a prolonged, sustained erection of the penis that occurs in the absence of sexual excitation and which may last hours to days, with or without pain .
The penis has two cavities, called the “corpora cavernosa,” which run the length of the organ and are filled with spongy tissue. Blood flows in and fills the open spaces in the spongy tissue to create an erection. Sexual desire commonly triggers erections. After an erection, the penis returns to its original flaccid state (detumescence). Priapism is the condition in which erections persist for a long time without sexual excitement.
There are three types of priapism:
- Ischemic priapism: This type is characterized by a nonsexual, persistent erection that can last for hours or days with little blood flow and the presence of poorly oxygenated (hypoxic) and overly acidic (acidotic) blood in the corpora cavernosa. The corpora cavernosa are rigid and tender to palpation and patients typically experience pain.
- Nonischemic priapism: This type of priapism is also a nonsexual, persistent erection, but it results from unregulated arterial blow flow in the corpora cavernosa. Cavernous blood gases are not hypoxic or acidotic. Typically, the penis is neither fully rigid nor painful.
- Stuttering priapism: This type of priapism is intermittent, it is a form of ischemic priapism in which unwanted painful erections occur repeatedly with intervening periods of detumescence.
Priapism is a relatively uncommon disorder. The incidence of priapism in men being treated for erectile dysfunction is estimated to range between 0.5 and 6%. It can occur in all age groups, including newborns. However, it usually affects males in the 5–10 and 20–50 age groups. Nonischemic priapism is also more rare than the ischemic form.
Causes and symptoms
Priapism is caused by abnormalities of the blood vessels and nerves that cause blood to become trapped in the corpora cavernosa of the penis. In most cases, priapism is caused by drugs injected into the penis to cause erection, or taken by mouth for erectile dysfunction, such as sildenafil (Viagra). Priapism can also be caused by blood clots , leukemia, sickle cell disease, and trauma to the spinal cord or to the genital area. Carbon monoxide poisoning and illicit drug use (marijuana and cocaine) have also been associated with priapism. A common cause of nonischemic priapism is injury to the penis or area between the scrotum and anus that ruptures the artery within the penis, with the result that blood can no longer circulate normally in the penis.
The diagnosis of priapism is obvious in the untreated patient. The priapism diagnosis seeks to differentiate between ischemic and nonischemic priapism. The evaluation is based on patient history, physical examination and laboratory or radiologic assessment. The laboratory evaluation usually includes a complete blood count (CBC) with special attention to the white blood count (WBC), white blood cell differential and platelet count. Acute infections or blood abnormalities that can cause priapism, such as sickle cell anemia , leukemia, may be identified by the CBC. A Doppler examination, which measures the blood flow of the penis, may also be performed. When in doubt, a blood gas measurement test is prescribed. This test is carried out by inserting a small needle in the penis to draw a blood sample for analysis. The test can help distinguish between ischemic and nonischemic priapism.
QUESTIONS TO ASK YOUR DOCTOR
- What is the cause of my priapism?
- Can it be cured?
- What does treatment involve?
- How likely is it to happen again?
- Can it be prevented?
The treatment of priapism depends on the cause. For instance, if caused by a drug, the drug in question is immediately stopped. If caused by a blood clot, surgery may be required to remove the clot and restore normal circulation to the penis.
Ischemic priapism is a medical emergency, while nonischemic priapism does not require emergency treatment. In both cases, treatment seeks to make the erection go away and preserve future erectile function. Ischemic priapism may be treated with ice packs and medications such as analgesics and opiates. Another approach involves injecting alpha-agonist medications, such as diluted neosynephrine, into the penis to open up the veins and re-establish blood circulation.
Alcohol abuse has been linked to priapism.
If required, nonischemic priapism can be treated by surgical therapy. Embolization is a procedure that reduces blood flow in the penis by obstructing the ruptured artery through insertion of especially designed coils. A ruptured artery may also be surgically tied off to help restore normal blood flow in the penis.
Acidotic —Characterized by acidosis, an abnormal increase in the acidity of the body's fluids.
Analgesic —A medication that can relieve pain by altering perception of pain without producing anesthesia or loss of consciousness.
Complete blood count (CBC) test —Blood test that provides important information about the kinds and numbers of cells in the blood.
Corpora cavernosa —Two chambers in the penis which run the length of the organ and are filled with spongy tissue. Blood flows in and fills the open spaces in the spongy tissue to create an erection.
Detumescence —The return of the penis to its original flaccid state, following erection.
Erectile dysfunction —Inability to achieve an erection, or dissatisfaction with the size, rigidity, or duration of erections.
Erection —Condition of the penis when it fills with blood and becomes rigid.
Hypoxic —Having too little oxygen.
Opiate —A drug that contains opium or a substance made from opium used to treat pain.
Penis —The male organ used for urination and sex.
Sickle cell disease —A genetic blood disease due to the presence of an abnormal form of hemoglobin, the molecule in red blood cells that transports oxygen from the lungs to body tissues.
White blood cell (WBC) differential test —Blood test that assesses the ability of the body to respond to and eliminate infection. It also detects the severity of allergic and drug reactions.
With prompt treatment, outcomes for most patients are very good. In some cases, nonischemic priapism may resolve itself spontaneously after days or months, with erectile function returning to normal. Prolonged priapism however, usually impairs erectile function permanently.
Depending on the cause, priapism may be prevented. For instance, drug-induced priapism can be prevented by abstaining from the medications or drugs that trigger episodes. Proper treatment of underlying conditions can also prevent priapism. Some medications are also available for the earliest stages of an abnormal erection.
Approximately 50% of men aged 65 years and 75% of men aged 80 have erectile dysfunction. Since priapism is mostly caused by the use or abuse of drugs taken to enhance or induce erections, men in these age groups should consider alternative treatments for erectile dysfunction such as psychological therapy or behavior-modification techniques that do not involve drugs.
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Monique Laberge Ph.D.